PIXEL DUMMY SUPPORT TUBE LIFTING DEVICE ENGINEERING CALCULATION

Transcription

1 PIXEL DUMMY SUPPORT TUBE LIFTING DEVICE ENGINEERING CALCULATION ATLAS Project Document No: Institute Document No. Created: Page: 1 of 51 ATL-IP-ER-0016 Modified: Rev. No.: 2.0 PIXEL DUMMY SUPPORT TUBE LIFTING DEVICE ENGINEERING CALCULATION ABSTRACT This document covers the design and mechanical validation of the Pixel Dummy Support Tube metallic structures. Scope of the LDT is the transport of the Dummy Support Tube - Main Body (DST-MB), containing the Atlas Pixel Detector Package, from the surface laboratory down to Atlas pit for installation. DST-MB is the airthight mechanical structure, fabricated by INFN Milano - Mechanical Design and Machine Workshop Department, to be used during surface test, transport and final installation of the Pixel Detector. Prepared by: Checked by: Approved by: Simone Coelli Mauro Monti

2 ATLAS Project Document No: Page: 2 of 51 History of Changes Rev. No. Date Pages Description of changes March April Created Modification after TIS comments

3 ATLAS Project Document No: Page: 3 of 51 TABLE OF CONTENTS 1.0 INTRODUCTION DESCRIPTION OF THE STRUCTURES STRUCTURAL BASE LIFTING SYSTEM WORKING DRAWINGS SET STRUCTURAL CALCULATION METHOD MATERIALS STATIC LOADS STATIC LOAD TEST LIFTING SYSTEM : STRUCTURAL CALCULATIONS TIE RODS OBLIQUE TIE ROD VERTICAL TIE ROD CENTRAL SUPPORT WITH EYEBOLT LIFTING PLATE AND BEAM HE B HEX-HEAD SCREW UNI M20 x EYEBOLT M30 UNI-ISO LONGITUDINAL BEAMS HE B CONNECTION COMPONENTS BETWEEN LIFTING SYSTEM AND TIE RODS L SUPPORT HEX-HEAD SCREW UNI M20 x HEX-HEAD SCREW UNI M20 x TIE ROD SUPPORT PLATE BUSHING STRUCTURAL BASE: STRUCTURAL CALCULATIONS DEFORMATION ANALYSIS OF STRUCTURAL BASE CONNECTION COMPONENTS BETWEEN STRUCTURAL BASE AND TIE RODS TIE-ROD SUPPORT PLATE BUSHING HEX-HEAD SCREW UNI M20 x EXTENSIONS AND STAY BOLTS EXTENSION STAY BOLTS REFERENCES...46 ANNEX A: OTHER MECHANICAL STRUCTURES FOR DST...47 A1 SUPPORT TABLE IN SURFACE...47 A2 SUPPORT STRUCTURE IN PIT...50

4 ATLAS Project Document No: Page: 4 of INTRODUCTION This document covers the LIFTING DEVICE TOOL (LDT) detailed design with relative engineering calculations. LDT is composed by the following mechanical structures: - STRUCTURAL BASE (fig. 1) is the support base of the DST during the entire cycle of tests and movements. - LIFTING SYSTEM (fig. 2) is the mechanical structure used for lifting and all the vertical movements of the DST, mainly for the descent to quota -80 meters in the ATLAS cavern, where it s foreseen a dedicate interface structure for the installation of Atlas Pixel Detector. The ANNEX A synthetically presents the two mechanical structures designed to support the DST: - SUPPORT TABLE IN SURFACE. - SUPPORT STRUCTURE IN PIT. 2.0 DESCRIPTION OF THE STRUCTURES 2.1 STRUCTURAL BASE The Structural Base is a carpentry in welded rectangular hollow shape and plates of several dimensions, realized in structural steel according to the drawing ATL-DST Rev.0. Two Extensions are fixed, using stay bolts, to the extremities of the Structural Base to support the DST transport extensions (or end plugs). The Extension is a carpentry in welded square hollow shape and plates of several dimensions, realized in structural steel according to the drawing ATL-DST Rev.0. In figure1 the Structural Base is represented with the two Extensions attached on it. Figure 1 - STRUCTURAL BASE WITH EXTENSIONS

5 ATLAS Project Document No: Page: 5 of LIFTING SYSTEM The Lifting System is realized from structural steel beams HE B 120 assembled with mechanical joints (fig. 2), according to the drawing ATL-DST Rev.0. Figure 2 - LIFTING SYSTEM The Structural Base is connected to the Lifting System by tie rods and bolts (fig. 3). Figure 3 - STRUCTURAL BASE CONNECTED TO THE LIFTING SYSTEM

6 ATLAS Project Document No: Page: 6 of 51 The Lifting System has to be connected to the bridge crane hook using its M30 eyebolt. The total lifted weight is N. The system hooking centre is adjustable to allow a perfect horizontal lifting. Figure 4 shows Lifting System with attached the Structural Base on which lies the DST-MB plus its extensions. Figure 4 LIFTING OF THE DST WITH END PLUGS DST-MB stands on eight dedicated plates of the Structural Base longitudinal beams, in corrispondence with the position of the eight supporting points of the Atlas Pixel Detector inside the DST, with the aim of minimize the deformations. 3.0 WORKING DRAWINGS SET This document refers to the following Working Drawings Set, loaded on EDMS data base in the document ATL-IP-ED Structural Base Working Drawings Set: - ATL-DST Rev.0 Structural Base Assembly - ATL-DST Rev.0 Structural Base Frame - ATL-DST Rev.0 Structural Base Extension Frame - ATL-DST Rev.0 Structural Base Details - ATL-DST Rev.0 Structural Base Details Lifting System Working Drawings Set: - ATL-DST Rev.0 Lifting System Assembly - ATL-DST Rev.0 Lifting System Details - ATL-DST Rev.0 Lifting System Details.

7 4.0 STRUCTURAL CALCULATION METHOD ATLAS Project Document No: Page: 7 of 51 The structural calculations have been carried out by analytical method and with FEM analysis: For analytical method we have taken as reference the code CNR-UNI 10011/97 Techinical Rules for Steel Construction with Admissible Tension calculation method. For FEM analisys we used ANSYS code (ANSYS WORKBENCH 10.0). In agreement with CERN-TIS indications, we used: Lifting structures Safety Factor: k = 2.4 generated by the multiplication of a load increment safety factor (=1.5) for a dynamic effect safety factor (=1.6). Admissible Tension: σ adm = f y / k = f y / 2.4 where: f y = minimum guaranteed material Yield Stress. 5.0 MATERIALS According to working drawings tables, materials used for the construction are non-alloy structural steels UNI EN 10025: S275- type quality JR - Hot-rolled structural steel S275- type quality J0 Rectangular hollow shapes E335 type Cold drawn and ground structural steel and Hot-rolled structural steel Table 1 shows the main mechanical characteristics of these steels: Table 1 EN NON-ALLOY STRUCTURAL STEELS

8 ATLAS Project Document No: Page: 8 of 51 The Resistance Class of the Hexagonal Head Screw UNI 5712 is: UNI EN 20898/1 (Nominal R p0,2 = 900 N/mm 2 ). The Resistance Class of the Hexagonal Nut UNI 5713 is: 10 - UNI EN 20898/ STATIC LOADS The static loads have been determined from the nominal weights of the structures to be lifted and rounded off (see Table 2). STRUCTURE NOMINAL WEIGHTS (N) ROUNDED WEIGHTS (N) ATLAS PIXEL DETECTOR DST MAIN BODY DST END PLUGS (N.2) LIFTING SYSTEM STRUCTURAL BASE STRUCTURAL BASE EXTENSIONS (N.2) TOTAL Table 2 STRUCTURES WEIGHTS 7.0 STATIC LOAD TEST Lifting System with attached Structural Base, lifted from ground, will be tested with a dummy load equal to 150 % of the nominal load in static conditions (lifting time 20 minutes). Structure deformations will be measured and controlled during the test. After unloading the structural parts will be checked to control complete recovery of elastic deformation and that no permanent unelastic deformation will remain. This test will be executed in the mechanical workshop in Italy before shipment to Cern. Interface test on the two support tables will be checked too. The test has then to be repeated in a formal way at Cern in presence of commissioning authorities.

9 ATLAS Project Document No: Page: 9 of LIFTING SYSTEM : STRUCTURAL CALCULATIONS 8.1 TIE RODS Deformation (elongation along the longitudinal axis) calculation of tie rods connection between Lifting System and Structural Base, during lifting with the static loads specified in par. 6.0, has been executed with FEM analysis. From the elongation values we derived tensile axial forces of tie rods used in the following structural calculations. We used a simplified model for the FEM analysis, specifically realized with 3D CAD solid modeler (UGS NX): We reduced the structures to ¼ (quarter model), taking advantage by the double symmetry of the system. We subdivided the total load in function of the pertinency length of each support element, as shown into the figures 5a and 5b. Figure 5a LOADS DISTRIBUTION ON STRUCTURAL BASE SUPPORT PLATES The portion of load (Q) concerning the Structural Base is calculated considering the sum of the following loads (ref. Table 2): Q = Pixel Detector weight + DST-MB weight + Structural Base weight = 9350 N Assuming a uniform distribution along the longitudinal axis, the distributed load q [N/m] is: q = Q / L = 1512 N/m

10 ATLAS Project Document No: Page: 10 of 51 Where: L = m DST-MB length With reference to the figure 5a, in which half DST-MB on Structural Base is represented, taking advantage by the symmetry of the system, the load portion attributable to each support plate is: Support Plate A : F A = q l 1 / 2 = 977 N 1000 N Support Plate B : F B = q l 2 / 2 = 1361 N 1400N Assuming, with a conservative hypothesis, than each Extension of the Structural Base totally supports the weight of the DST end plug (275 N) and a Pixel load of 490 N (due to the corrugated panels weight), the portion of load of pertinency of each Extension (Q 1 ), is: Q 1 = 765 N With reference to the simplified model for FEM analysis that we have before described (quarter model), we consider only half Extension (longitudinal axis symmetry), and the load supported is therefore: Q 1/2 = Q 1 / 2 = N distributed on the three support plates, as shown into the figure 5b, where: Q 6 = Q 1/2 / 3 = N The dead load of the half Extension (Q 5 = 62.5 N), is applied in barycentric position, at distances y b,x b calculated by solid modeler NX3 (see figure 5b): y b = mm (longitudinal axis direction) x b = 73 mm (transversal axis direction). The resultant F c of the forces system of the figure 5b is: F c = 445 N 450 N applied at distances: y d = mm 523 mm, x d = 27.4 mm 28 mm.

11 ATLAS Project Document No: Page: 11 of 51 Figure 5b LOAD DISTRIBUTION ON STRUCTURAL BASE EXTENSION Figure 5c shows the quarter model calculation environment with the loads applied according to the previous calculations: the half extension isn t represented but there is only a remote force of 450 N in the calculated position. The coordinates of the remote force displayed are relative to the local coordinate system represented in the box of the figure 5c, with the zero point coincident to the middle of the external edge of the Structural Base. Figure 5c QUARTER MODEL CALCULATION ENVIRONMENT WITH FORCES Figure 6 shows the quarter model calculation environment with the constraints used in modelization: N.1 Fixed support constraint on the lifting plate of the Lifting Sistem, in correspondence of the eyebolt axys. N.8 Frictionless support constraints on the border surfaces of the model, obtained from the "cut" of the beams and the shapes with the symmetry planes (every surface is bounded to remain in the vertical plane that contains it, but free to slide without friction in the same one).

12 ATLAS Project Document No: Page: 12 of 51 Figure 6 QUARTER MODEL CALCULATION ENVIRONMENT WITH CONSTRAINTS In order to determine the values of tie rods elongation under load, we executed two directional deformation analysis OBLIQUE TIE ROD The oblique tie rod is the Item 13 in drawing ATL-DST Rev.0. Here follow the characteristics of the oblique tie rods: Material: Structural Steel EN E335GC+SL Yield Stress (R p0,2 ): f y = 480 N/mm² (10 mm < tie rod diam. 16 mm) Young s Modulus: E = N/mm² Admissible Tension: σ adm = f y / k = 480 / 2.4 = 200 N/mm² Tie rod diameter: d = 12 mm Transversal Section Area: A = 113 mm² Thread: M 12 Thread kern diameter: d n = 9.85 mm Resisting Section Area: A res = 76 mm² Tie-rod free length (in the model): L = 1746 mm

13 ATLAS Project Document No: Page: 13 of 51 FEM directional deformation analysis has been executed orienting the X axis of the coordinate system parallel to the longitudinal axis of the oblique tie rod. The results of the FEM directional deformation analysis along X axis, with the two values at tie rod extremities, are shown in figure 7. Figure 7 LIFTING SYSTEM: OBLIQUE TIE ROD DEFORMATION ANALYSIS The value of the elongation ( L) of the oblique tie rod is: L = = mm Calculated tensile axial force (N 1 ) of the oblique tie rod *: N 1 = A E L / L = 3280 N Note *: in the quarter model tie rod has diameter d = 12 mm (without threads). Normal mean tension (σ) of the oblique tie rod (threaded section) verification: σ = N 1 / A res = 43 N/mm 2 σ adm = 200 N/mm 2

14 ATLAS Project Document No: Page: 14 of VERTICAL TIE ROD The vertical tie rod is the Item 14 in drawing ATL-DST Rev.0. The characteristics of the vertical tie rods are the same of the oblique tie rods, except the length L: Tie rod free length (in the model): L = 698 mm FEM directional deformation analysis has been executed orienting the Z axis of the coordinate system parallel to the longitudinal axis of the vertical tie rod, with the same direction of the load. The results of the FEM directional deformation analysis along Z axis, with the two values at tie rod extremities, are shown in figure 8. Figure 8 LIFTING SYSTEM: VERTICAL TIE ROD DEFORMATION ANALYSIS The value of the elongation ( L) of the vertical tie rod is: L = = mm Calculated tensile axial force (N 2 ) of the vertical tie rod *: N 2 = A E L / L = 1239 N Note *: in the quarter model tie rod has diameter d = 12 mm (without threads).

15 ATLAS Project Document No: Page: 15 of 51 Normal mean tension (σ) of the vertical tie rod (threaded section) verification: σ = N 2 / A res = 16 N/mm 2 σ adm = 200 N/mm CENTRAL SUPPORT WITH EYEBOLT Figure 9 is extracted from Lifting System assembly drawing ATL-DST Rev.0, showing the Central Support with lifting eyebolt. Lifting eyebolt with threaded stem M30 (Ref. Item 23), is screwed in the Central Support, formed by the Lifting Plate (Ref. Item 19) and beam HE B 100 (Ref. Item 20), connected with four high resistance hexagonal head screws M20 (Ref. Item 22), each of them with hexagonal nut UNI 5713 M20-10 (Rif. Item 10), spring washer UNI 9195-B-20 (Ref. Item 11), square washer (Ref. Item 21). Central Support position can be regulated in order to align the eyebolt with the barycentric axis. After regulation the nuts will be also locked with threadlocker. The maximum static load on eyebolt, calculated at the par.6.0, is F = N. Figure 9 CENTRAL SUPPORT WITH EYEBOLT OF THE LIFTING SYSTEM Resistance verifications of the components of the lifting Central Support are presented in the following paragraphs.

16 ATLAS Project Document No: Page: 16 of LIFTING PLATE AND BEAM HE B 100 The characteristics of the two components are: Lifting Plate (Ref. Item 19 - drawing ATL-DST Rev.0) Material: Structural Steel EN E335 Yield Stress min.: f y = 315 N/mm² (40 mm < thk. 63 mm) Admissible Tension: σ adm1 = f y / k = 315 / 2.4 = 131 N/mm² Beam HE B UNI (Ref. Item 20 - drawing ATL-DST Rev.0): Material: Structural Steel EN S275JR Yield Stress min.: f y = 275 N/mm² Admissible Tension: σ adm2 = f y / k = 275 / 2.4 = 115 N/mm² The square washer (Ref. Item 21) is also realized in structural steel EN S275JR. The total deformation and Von Mises equivalent stress calculations have been executed with FEM analysis: the figure 10 shows the calculation environment. The total load F = N is divided in two equal forces, each of 6000 N, applied on the two support surfaces of beam HE B (evidenced in figure 10 with green color). A Fixed support constraint has been applied on the Lifting Plate in correspondence of eyebolt hole (evidenced in the box of figure 10 with green color). Figure 10 - CENTRAL SUPPORT OF THE LIFTING SYSTEM: CALCULATION ENVIRONMENT

17 ATLAS Project Document No: Page: 17 of 51 Figure 11 shows the results of total deformation analysis, where the maximum deformation is : δ max = mm Figure 11 - CENTRAL SUPPORT OF THE LIFTING SYSTEM: TOTAL DEFORMATION ANALYSIS Figure 12 shows the results of Von Mises equivalent stress analysis (1 MPa = 1 N/mm²). The equivalent stress maximum value is: σ max = 53.2 N/mm². σ max = 53.2 N/mm² < σ adm1 = 131 N/mm² σ max = 53.2 N/mm² < σ adm2 = 115 N/mm²

18 ATLAS Project Document No: Page: 18 of 51 Figure 12 - CENTRAL SUPPORT OF THE LIFTING SYSTEM: EQUIVALENT STRESS ANALYSIS HEX-HEAD SCREW UNI M20 x The characteristics of the four screws fixing the Central Support are the following: Ref.: Item 22 - drawing ATL-DST Rev.0 Type: High resistance screw for carpentry UNI 5712 Bolt class: UNI EN 20898/1 Yield Stress (Nominal R p0,2 ): f y = 900 N/mm² Admissible tensile tension: σ b,adm = f y / k = 900 / 2.4 = 375 N/mm² Admissible shear tension τ b,adm = σ b,adm / 3 = 217 N/mm² Diameter: d = 20 mm Thread: M20 pitch 2.5 mm Thread kern diameter: d n = mm Resisting Section Area : A res = 225 mm² Screws are tensile stressed by the lifted load, with normal mean tension (σ t1 ) defined according to Section CNR-UNI 10011/97 : σ t1 = (F / n) / A res = 13 N/mm² Where : F = N maximum load n = 4 number of screws Tightening torque of each bolt (T s ) produces a tensile stress (N s ) in the bolt body, and a torque (T s1 ) due to threads friction, this has to be limited during assembling, using a dynamometer wrench.

19 ATLAS Project Document No: Page: 19 of 51 Assuming, in first approximation (with final verification), a maximum tensile stress in the bolt (given from the sum N s,max + F/n) equal to 70% of the product σ b,adm A res : N s,max + (F / n) = 0.7 σ b,adm A res => N s,max = 0.7 σ b,adm A res - (F / n) = N The normal maximum tension (σ t2 ) in the bolt, produced by the the tensile stress N s,max, is: σ t2 = N s,max / A res = 249 N/mm² The maximum normal tension (σ max ) is: σ max = σ t1 + σ t2 = 262 N/mm² < σ b,adm = 375 N/mm² The tightening torque T s,max [N m] producing the tensile stress N s,max [N], for screws with metric thread, basic pitch and nominal thread diameter d [mm], according to Section CNR-UNI 10011/97, would be: T s,max = 0.2 N s,max d = Nmm 224 Nm The torque (T s1 ) due to the threads friction in the bolt body can be calculated following the indications of par. 14 Mechanical Engineer Handbook (P. Andreini - Hoepli edition): T s1 = N s,max tg (α + φ) (d m / 2) = Nmm Where : α = 2.5 thread helix mean angle φ = arctg (f 1 / cos θ/2 ) = 9.8 f 1 = 0.15 (estimate) friction factor between screw thread nut thread θ = 60 thread profile angle d m = 18.4 mm thread mean diameter The maximum tangential tension (τ max ) produced by T s1 results: τ max = (16 T s1 ) / π d n ³ = 118 N/mm² < τ b,adm = 217 N/mm² According to section CNR-UNI 10011/97, it should be : (τ max / τ b,adm )² + (σ max / σ b,adm )² 1 Final verification : (τ max / τ b,adm )² + (σ max / σ b,adm )² = Finally, we verify that once locked the bolts of the Central Support with the torque T s,max, a friction joint is realized with the longitudinals beams HE B 120, in order to avoid arrangements in load condition. The maximum transmissible force for friction from every bolt (V f,n ), stressed from the axial forces N s,max and N = F/n, can be calculated according to Section CNR-UNI 10011/97: V f,n = µ (N s,max / γ f ) (1 N/ N s,max ) = N Where: µ = 0.3 (estimate) friction factor between the contact surfaces γ f = 1.25 reduction factor The Central Support, with the four bolts locked by torque T s,max = 224 Nm, can transfer for friction an overall horizontal force (V f,nt ): V f,nt = n V f,n = N

20 ATLAS Project Document No: Page: 20 of EYEBOLT M30 UNI-ISO 3266 Eyebolt (Ref. Item 23 - drawing ATL-DST Rev.0), with thread stem M30, forged in one piece, is certificated suitable for employment by the supplier (CE conformity requested), therefore it is no subordinated to calculation. The maximum nominal load in vertical lifting for M30 eyebolt UNI-ISO 3266 is N (2.5 t), against the maximum effective load value of N. Eyebolt will be locked on the Lifting Plate threaded hole with threadlocker. 8.3 LONGITUDINAL BEAMS HE B 120 The characteristics of the two longitudinal beams of the Lifting Sistem are: Beam HE B UNI (Ref. Item 1 - drawing ATL-DST Rev.0): Material: Structural Steel EN S275JR Yield Stress min.: f y = 275 N/mm² Admissible Tension: σ adm = f y / k = 275 / 2.4 = 115 N/mm² The total deformation and Von Mises equivalent stress calculations have been executed with FEM analysis : the figure 13 shows the calculation environment. The total load F = N has been subdivided in four equal forces, each of 3000 N, applied on the extremity surfaces of beams HE B (evidenced in figure with green color). A Fixed support constraint has been applied on the Lifting Plate in correspondence of eyebolt hole. Figure 13 - LONGITUDINAL BEAMS OF THE LIFTING SYSTEM : CALCULATION ENVIRONMENT Figure 14 shows the total deformation analysis, where the maximum deformation is: δ max = 0.56 mm.

21 ATLAS Project Document No: Page: 21 of 51 Figure 14 - LONGITUDINAL BEAMS OF THE LIFTING SYS. : TOTAL DEFORMATION ANALYSIS Figure 15 shows the results of Von Mises equivalent stress analysis (1 MPa = 1 N/mm²). The equivalent stress maximum value is: σ max = 26.4 N/mm². σ max = 26.4 N/mm² < σ adm = 115 N/mm² Figure 15 - LONGITUDINAL BEAMS OF THE LIFTING SYS. :EQUIVALENT STRESS ANALYSIS

22 ATLAS Project Document No: Page: 22 of CONNECTION COMPONENTS BETWEEN LIFTING SYSTEM AND TIE RODS The connection between Lifting System and tie rod support plates (see figure 16) is realized with four L supports (Ref. Item 7 - drawing ATL-DST Rev.0). Each L support is fixed to the HE B beams of the Lifting System with two high resistance hexagonal head screws M20 (Ref. Item 8), each of them with hexagonal nut UNI 5713 M20-10 (Ref. Item 10) and spring washer UNI 9195-B-20 (Ref. Item 11). The tie rod support plate (Ref. Item 12) is hinged to the L Support with high resistance hexagonal head screw M20 (Ref. Item 18), which is the fixed rotation pivot, and a bronze bushing (Ref. Item 17) as antifriction bearing. The screw Item 18 is fixed by hexagonal nut UNI 5713 M20-10 (Ref. Item 10) with spring washer UNI 9195-B-20 (Ref. Item 11); the nut will be locked also with threadlocker. In the following sub-paragraphs resistance verifications are presented: Figure 16 CONNECTION COMPONENTS BETWEEN LIFTING SYSTEM AND TIE RODS L SUPPORT Characteristics of L support (Ref. Item 7 - drawing ATL-DST Rev.0), obtained by hot-rolled L EN x75x10, are: Material: Structural Steel EN E335 Yield Stress min.: f y = 335 N/mm² (thk. 16 mm) Admissible Tension: σ adm = f y / k = 335 / 2.4 = 140 N/mm²

23 ATLAS Project Document No: Page: 23 of 51 For L Support resistance calculations, we make the hypothesis of the equal division of the load on the four L Supports of the Lifting System. Figure 17 shows the dimensions of the L Support, with the loads applied. Figure 17 L SUPPORT: DIMENSIONS AND LOADS In the paragraph 8.1 we calculated the tie rods tensile axial forces, these are tranfered to L Support by connection bolts. The known forces are: F 1 = N 1 = 3280 N Force of the oblique tie rod F 2 = N 2 = 1239 N Force of the vertical tie rod The F 1 components are: F 1x = F 1 cos30 = 2841 N F 1y = F 1 sin30 = 1640 N According to CNR-UNI 10011/97 (Section Bolted joints, Section 6 - Verifications of joints resistance), we executed the following verifications: 1. Distance between hole centers and distance from the borders (Ref. Section CNR-UNI 10011/97) L Support bolts, diameter d = 20 mm, are housed into holes of diameter d h = 21 mm, according to Section CNR-UNI 10011/97 (oversize of the hole, related to the diameter d of bolt, must be 1 mm for diameters 20 mm, when is ammissible the arrangement of the joint under load). Criterions applied to L Support are the same used for the bolted joints. Indicating with t min the smaller thickness of the elements to be connected, that is L Support thickness (t min = 10 mm), it must be:

24 ATLAS Project Document No: Page: 24 of Distance between holes axis and free border (a), in the Y direction, considering that the L Support is an element under traction stress. Requested condition: a 2 d Verifications: a = 60 mm 2 d = 40 mm a = 65 mm 2 d = 40 mm 1-2 Distance between holes axis and the not stiffened border (a), in Y direction. Requested condition: a 6 t min Verification: a = 60 mm 6 t min = 60 mm 1-3 Distance between holes axis and the stiffened border (a), in Y direction. Requested condition: a 9 t min Verification: a = 65 mm 9 t min = 90 mm. 1-4 Distance between holes axis and free border (a 1 ), in X direction (perpendicular to Y direction). Requested condition: a d Verification: a 1 = 30 mm 1.5 d = 30 mm 1-5 Distance between holes axis and the not stiffened border (a 1 ), in X direction. Requested condition: a 1 6 t min Verification: a 1 = 30 mm 6 t min = 60 mm. 1-6 Distance between holes centers (p), for element under traction stress. Requested condition: 25 t min p 3 d Verification: 25 t min = 250 mm p = 65 mm 3 d = 60 mm 2. Heading Verification (Ref. Section CNR-UNI 10011/97) The heading resistance is verified in reference to the greater force (oblique) F 3 = 3280 N. Pressure on hole profile (σ rif ), relative to the diametrical projection of cylindrical surface of the bolt (d diameter), must be: σ rif α σ adm Where : α = a / d 2.5 a = a 1 / cos 30 = 34.6 mm distance between the center of the bolt hole and free border, along force direction. α = a / d = 1.73 α σ adm = 242 N/mm² σ rif = F 3 / (d t min ) = 16 N/mm² Final heading verification : σ rif = 16 N/mm² < α σ adm = 242 N/mm²

25 ATLAS Project Document No: Page: 25 of 51 FEM ANALYSIS The total deformation and Von Mises equivalent stress calculations have been executed with FEM. Figure 18a shows the calculation environment with constraints: a Fixed support constraint has been applied on the contact surface with the HE B beam flange (evidenced in figure with green color), and a Compression Only Support constraint has been applied in correspondence of the contact surface with the HE B beam core (evidenced in figure with blue color). Figure 18a L SUPPORT: CALCULATION ENVIRONMENT WITH CONSTRAINTS Figure 18b shows the calculation environment with loads : the forces transfered to the L Support by the tie rods (F 1 = 3280 N, F 2 = 1239 N) have been applied on the bushings fastened with bolts. Figure 18b L SUPPORT: CALCULATION ENVIRONMENT WITH FORCES

26 ATLAS Project Document No: Page: 26 of 51 Figure 19 shows the total deformation analysis: the maximum deformation is δ max = 0.07 mm. Figure 19 L SUPPORT : TOTAL DEFORMATION ANALYSIS Figure 20 shows the results of Von Mises equivalent stress analysis (1 MPa = 1 N/mm²). The equivalent stress maximum value is: σ max = 44.2 N/mm². σ max = 44.2 N/mm² < σ adm = 140 N/mm² Figure 20 L SUPPORT : EQUIVALENT STRESS ANALYSIS

27 ATLAS Project Document No: Page: 27 of HEX-HEAD SCREW UNI M20 x Connection between tie rod support plate and L Support (see figure 16) is carried out by high resistance hexagonal head screw M20 UNI 5712 bolt class 10.9 (Ref. Item 18 drawing ATL-DST Rev.0). Characteristics of the screw are the same already listed for the screws of the par (the only exception being the different length). The admissible shear tension (τ b,adm ) is calculated from the tensile admissible tension (σ b,adm ): σ b,adm = 375 N/mm² τ b,adm = σ b,adm / 3 = 217 N/mm² The screw mainly stressed is the one connected to oblique tie-rod, which tranfers the force F 1 = 3280 N. The screw is subjected to shearing stress and to bending moment (due to distance b = 20 mm between the tie-rod axis and the L Support, as shown in figure 21), therefore the resistance verification is executed in agreement to section CNR-UNI 10011/97. With reference to figure 21, the mainly stressed screw section is in section A-A, where screw is threaded. Figure 21 LATERAL VIEW OF THE L SUPPORT Considering the screw as a fixed cantilever pivot, the bending moment (M), due to F 1, is : M = F 1 (b + t) = Nmm = 98.4 Nm Where : b = 20 mm t = 10 mm distance between tie rod axis and L Support thickness of L Support

28 ATLAS Project Document No: Page: 28 of 51 The module of bending resistance (W) of the screw core section is : W = π d n ³ / 32 = 476 mm 3 Where : d n = mm screw core diameter The maximum normal tension (σ max,b ), due to M, is : σ max,b = M / W = 207 N/mm² The mean tangential tension (τ m,s ) due to shearing stress (F 1 ), is : τ m,s = F 1 / A res = 15 N/mm² Where : A res = 225 mm² resisting section area The screw is also subjected to tensile stress by axial force N s, due to the tightening torque. The force N s must be limited in order not to exceed the admissible tension of the compressive stress in the bronze bushing (Ref. item 17 drawing ATL-DST Rev.0). The maximum N s value, calculated in the following paragraph 8.4.5, is : N s,max = 8700 N. The normal tension (σ m,t ), due to N s,max, is : σ m,t = N s,max / A res = 39 N/mm² According to the section CNR-UNI 10011/97, using a dynamometer wrench, the maximum tightening torque T s,max [Nm] should be : T s,max = 0.2 N s,max d = Nmm 35 Nm According to the calculation method in paragraph 8.2.2, the torque (T s1 ), due to the threads friction can be estimated : T s1 = Nmm And the maximum tangential tension (τ max,t ), due to T s1, is: τ max,t = T s1 16 / (π d n ³) = 18 N/mm² The maximum normal tension (σ max ) of stretched fibres in the screw is : σ max = σ max,b + σ m,t = 246 N/mm² < σ b,adm = 375 N/mm² The maximum tangential composed tension (τ max ) is : τ max = τ max,t + τ m,s = 33 N/mm² < τ b,adm = 217 N/mm²

29 ATLAS Project Document No: Page: 29 of 51 According to section CNR-UNI 10011/97, should result: Final verification: (τ max / τ b,adm )² + (σ max / σ b,adm )² 1 (τ max / τ b,adm )² + (σ max / σ b,adm )² = HEX-HEAD SCREW UNI M20 x Connection between L Support and HE B 120 beam (see figure 16), is carried out by two high resistance hexagonal head screws M20 UNI 5712 bolt class 10.9 (Ref. Item 8 drawing ATL-DST Rev.0). Characteristics of the screws are the same already listed for the screws of the paragraph and the paragraph (the only exception being the different length): Admissible tensile tension σ b,adm = 375 N/mm² Admissible shear tension τ b,adm = 217 N/mm² The screws must realize a friction joint between the contact surfaces of the L Support and the beam HE B 120, in order to avoid arrangements of the union under load (Ref. section CNR-UNI 10011/97), in F 1x force direction (see figure 17). Friction force transmissible by every bolt (V f,o ), multiplied for bolts number n = 2, must be, at least, equal to F 1x : n V f,o F 1x = 2841 N => V f,o,min = 1421 N V f,o can be calculated according to Section CNR-UNI 10011/97: Where : V f,o = µ N s / γ f N s axial force in screw body due to tightening torque µ = 0. 3 (estimate) friction factor between the contact surfaces γ f = 1.25 reduction factor => N s,min = V f,o,min γ f / µ = 5921 N In order to have a friction joint condition, the minimum tightening torque, using a dynamometer wrench, for the bolt (T s,min ), must be (Ref. Section CNR-UNI 10011/97): Ts,min = 0.2 N s,min d = Nmm 24 Nm For uniformity with the bolt of the previous paragraph, the torque has been assumed as: T s = 35 Nm

30 ATLAS Project Document No: Page: 30 of 51 The tensile stress of the screw body, due to maximun tightening torque T s, is: N s = 8700 N The normal tension (σ m,t ), due to N s,max is: σ m,t = N s / A res = 39 N/mm² < σ b,adm = 375 N/mm² The torque (T s1 ), in the bolt body (see paragraph 8.4.2) is: T s1 = Nmm The maximum tangential tension (τ max,t ), due to T s1, is: τ max,t = T s1 16 / (π d n ³) = 18 N/mm² < τ b,adm = 217 N/mm² Final verification, according to Section CNR-UNI 10011/97: (τ max,t / τ b,adm )² + (σ m,t / σ b,adm )² = TIE ROD SUPPORT PLATE The tie rod support plate (Ref. Item 12 - drawing ATL-DST Rev.0) is hinged to the L Support (see figure 16): the bolt (Ref. Items 18,10,11) is the fixed rotation pivot and the bronze bushing (Ref. Item 17) is the antifriction bearing. Figure 23 shows tie rod support plate dimensions. Figure 22 TIE ROD SUPPORT PLATE DIMENSIONS

31 ATLAS Project Document No: Page: 31 of 51 Characteristics of the tie rod support plate, machined from cold drawn plate, are: Material: Structural Steel EN E335GC+C Yield Stress (R p0,2 ): f y = 390 N/mm² (16 mm < thk. 40 mm) Admissible Tension: σ adm = f y / k = 390 / 2.4 = 163 N/mm² Tie-rod support plate operates as a bracket of a hinge with pivot, stressed by traction force, therefore verifications carried out refer to the Section CNR-UNI 10011/97. The maximum tensile stress is for the support plate of the oblique tie rod : F t = F 1 = 3280 N. 1. Verification of the resistant diametrical section (Ref. Section CNR-UNI 10011/97). 1-1 The resistant diametrical sections, perpendicular to the tensile stress, must respect the following limitation (ref. figure 22): Resistance condition : Where : b = 11.5 mm t = 20 mm 2 b t 1.4 F t / σ adm radial thickness, perpendicular to the force plate thickness Verification : 2 b t = 460 mm² 1.4 F t / σ adm = 28 mm² 1-2 The resistant diametrical section, parallel to the tensile stress, must respect the following limitation (ref. figure 22): Resistance condition : Where : a = 11.5 mm t a F t / σ adm radial thickness, parallel to the force Verification : t a = 230 mm² F t / σ adm = 20 mm² 1-3 Must be, also : b / t 8 Verification : b / t = Heading Verification (Ref. Section CNR-UNI 10011/97) Pressure on the hole profile of the tie rod support plate (σ rif ), transfered by bushing, relative to the diametrical projection of the cylindrical surface of coupling, must be : σ rif σ adm σ rif = F t / (d h t) = 6 N/mm²

32 ATLAS Project Document No: Page: 32 of 51 Where : d h = 27 mm bushing housing hole diameter Final heading verification : σ rif = 6 N/mm² 1.35 σ adm = 220 N/mm² BUSHING Characteristics of the bushing (Ref. Item 17 - drawing ATL-DST Rev.0) are the following : Material: Mechanical Bronze B14 GCuSn12 UNI 7013 Yield Stress (R p0,2 ) min.: f y = 145 N/mm² Admissible Tension: σ adm = f y / k = 145 / 2.4 = 60 N/mm² Figure 23 shows bushing dimensions: Figure 23 BUSHING DIMENSIONS 1. Heading Verification The pressure on the external cylindrical surface of the bushing (σ rif,e ) is equal to the pressure σ rif calculated in the previous paragraph : σ rif,e = 6 N/mm² σ adm = 60 N/mm²

33 ATLAS Project Document No: Page: 33 of 51 The pressure on the internal cylindrical surface of the bushing (σ rif,i ), relative to the diametrical projection of the cylindrical surface of the bolt, must respect the following limitation: σ rif,i = F b / (d l b ) σ adm Where : F b = F 1 = 3280 N l b = 30.5 mm bushing length engaged by the bolt d = 20 mm bolt diameter Final heading verification : σ rif,i = 5. 4 N/mm² < σ adm = 60 N/mm² 2. Compressive stress resistance Bushing is compressive stressed by the axial force N s, due to the bolt tightening torque T s, that must be limited (ref. paragraph 8.4.2). The minimum supporting surface is located in correspondence to the washer under the head of the screw, and, with reference to figure 23, is a circular crown that, without chamfers, has the following dimensions: d e = 25 mm external diameter d i = 21 mm internal diameter A = π (d e ² d i ² ) / 4 = 145 mm² contact washer area Maximum axial force (N s,max ) to be applied should be (ref. paragraph 8.4.2): N s,max A σ adm = 8700 N

34 ATLAS Project Document No: Page: 34 of STRUCTURAL BASE: STRUCTURAL CALCULATIONS Figure 24 is extracted from Structural Base assembly drawing ATL-DST Rev.0. The main frame of Structural Base (Ref. Item 1) is realized with cold formed rectangular hollow shapes (60x100 4 mm thickness), according to EN 10219, which have the following characteristics: Material: Structural Steel EN S275J0H Yield Stress: f y = 275 N/mm² Admissible Tension: σ adm = f y / k = 275 / 2.4 = 115 N/mm² The DST-MB, with Atlas Pixel Detector inside, is supported by eight plates (Ref. Item 11), placed on the two longitudinal shapes of the frame. The distance between axis of the plates item 11, is the same of the support points of Atlas Pixel Detector, and is the same of the connection bolts of the Lifting System tie-rods. Figure 24 - STRUCTURAL BASE Main frame rectangular hollow shapes are assembled by means of arc welding with cored electrodes or FCAW (welder qualified by EN 287, welding process qualified by EN 288, as TIS request). Shapes weldings aren t essential for the structural resistance, being the DST-MB supported by the two longitudinal shapes of the main frame, monolithic pieces. Shapes weldings don t need really analytical verification, but are only required to be executed according to working drawings, in respect of the codes EN 287, EN 288 suggested by CERN-TIS. Controls by visual inspection and penetrating liquids or magnetic analysis are foreseen on all connections.

35 ATLAS Project Document No: Page: 35 of DEFORMATION ANALYSIS OF STRUCTURAL BASE The main design requirement for the Structural Base is the coplanarity of DST-MB support surfaces (the planes of the eight plates Item 11): the maximum levelness tolerance admissible is 2 mm under load. This design requirement will be satisfied by: Preliminary analysis of the total deformation of the frame under load, detailed in this paragraph (see figure 25). Expected elastic deformation value under load, in correspondence of the support point of DST- MD more distant, is about 1 mm. Accurate fabrication of the Structural Base frame, with maximum levelness tolerance 1 mm. Fabrication of support plates (Item 11) as separate elements from the frame, with levelling and clamping screws, designed with the purpose to finely regulate the support surfaces. The total deformation analysis of Structural Base connected to the Lifting System, under load condition, has been executed by FEM, using the same simplified model described at paragraph 8.1 (quarter model). The calculation environment is represented in the previous figures 5c and 6 of paragraph 8.1. Figure 25 shows the results of total deformation analysis. Figure 25 STRUCTURAL BASE TOTAL DEFORMATION ANALYSIS

36 ATLAS Project Document No: Page: 36 of 51 The maximum deformation of the Structural Base frame is δ max = 1.7 mm. In correspondence of the support plate more distant location point, the local deformation of the Structural Base frame is: δ = 1.4 mm From the FEM analysis of the quarter model, the maximum Von Mises equivalent stress of the Structural Base frame is: σ max 48 N/mm² < σ adm = 115 N/mm² 9.2 CONNECTION COMPONENTS BETWEEN STRUCTURAL BASE AND TIE RODS Figure 26 is extracted from Structural Base assembly - drawing ATL-DST Rev.0. The connection between Structural Base and the tie-rods is realized with the components represented: the tie rod support plate (Ref. Item 16) is hinged to the Structural Base frame with high resistance hexagonal head screw M20 (Ref. Item 19), which is the fixed rotation pivot, and a bronze bushing (Ref. Item 20) as antifriction bearing. The screw Item 19 is fixed by hexagonal nut UNI 5713 M20-10 (Ref. Item 17) with spring washer UNI 9195-B-20 (Ref. Item 18). When the Lifting System will be connected to the Structural Base, for the descent in Atlas pit, the nut will be locked also with threadlocker. In the following sub-paragraphs resistance verifications are presented. Figure 26 - CONNECTION COMPONENTS BETWEEN STRUCTURAL BASE AND TIE-RODS

37 ATLAS Project Document No: Page: 37 of TIE-ROD SUPPORT PLATE Ref. Item 16 - drawing. ATL-DST Rev.0. => See resistance verification of tie rod support plate in the paragraph (having the same geometrical, mechanical and stress characteristics) BUSHING Ref. Item 20 - drawing. ATL-DST Rev.0. => See resistance verification of bushing in the paragraph (having the same geometrical, mechanical and stress characteristics) HEX-HEAD SCREW UNI M20 x The connection between tie rod support plate and Structural Base frame (see figure 27) is carried out by M20 high resistance hexagonal head screw for carpentry UNI 5712 bolt class 10.9 (Ref. Item 19 drawing ATL-DST Rev.0). Characteristics of the screw are the same listed for screws in paragraph and paragraph (the only exception being the different length): Admissible tensile tension σ b,adm = 375 N/mm² Admissible shear tension τ b,adm = 217 N/mm² The screw mainly stressed is the one connected to oblique tie-rod, transmitting the force F 1 = 3280 N. The screw is subjected to shearing stress and to bending moment (due to distance b = 20 mm between tie-rod axis and the frame, as shown in figure 27), therefore the resistance verification is executed in agreement to section CNR-UNI 10011/97. Figure 27 SECTION VIEW OF CONNECTION BETWEEN TIE-ROD AND FRAME

38 ATLAS Project Document No: Page: 38 of 51 After initial adjustment under load with recovery of the hole-bolt clearance (contact between surfaces), we assume that the screw works as a fixed cantilever pivot, subjected to shearing stress and to bending moment: the maximum stressed section is A-A section of figure 27, in correspondence of the not threaded stem of the screw. The bending moment (M), due to F 1, is: M = F 1 b = Nmm The resistance bending module (W) of not threaded screw section is: W = π d 3 / 32 = 785 mm 3 Where : d = 20 mm diameter of not threaded screw body The maximum normal tension (σ max,b ), due to M, is: σ max,b = M / W = 84 N/mm² The mean tangential tension (τ m,s ) due to shearing stress, is: τ m,s = F 1 / A = 11 N/mm² Where : A = 314 mm² Section area of not threaded screw body Values of the following parameters are equal to the same already calculated in paragraph 8.4.2: Bolt tightening torque: T s,max = 35 Nm Bolt axial force due to tightening torque: N s,max = 8700 N Torque in the bolt body : T s1 = Nmm The normal tension (σ m,t ), due to N s,max, is: σ m,t = N s,max / A = 28 N/mm² The maximum tangential tension (τ max,t ), due to T s1, is: τ max,t = T s1 16 / (π d³) = 11 N/mm² The maximum normal tension (σ max ) in the A-A section is: σ max = σ max,b + σ m,t = 112 N/mm² < σ b,adm = 375 N/mm² The maximum tangential composed tension (τ max ) in the A-A section is: τ max = τ max,t + τ m,s = 22 N/mm² < τ b,adm = 217 N/mm² According to section CNR-UNI 10011/97, should result: (τ max / τ b,adm )² + (σ max / σ b,adm )² 1 Final verification : (τ max / τ b,adm )² + (σ max / σ b,adm )² = 0.1 1

39 ATLAS Project Document No: Page: 39 of EXTENSIONS AND STAY BOLTS DST-MB transport extensions (end plugs) are supported by the two Extensions fixed to the two Structural Base ends by stay bolts (see figure 28). Weight of each transport extension is 275 N. The maximum weight of Atlas Pixel Detector Package (corrugated panels and connectors) expected to be supported by each Extension is estimated be 490 N (conservative hypothesis), then the total load on each Extension for calculation become Q 1 = 765 N (ref. paragraph 8.1). Figure 28 STRUCTURAL BASE EXTENSION EXTENSION The Extension (Ref. Item 2 drawing ATL-DST Rev.0) is realized by square hollow shapes (40x40 2 mm thickness), which have the following characteristics: Material: Structural Steel EN S275J0H Yield Stress: f y = 275 N/mm² Admissible Tension: σ adm = f y / k = 275 / 2.4 = 115 N/mm² The square hollow shapes are assembled by means of arc welding with cored electrodes or FCAW (welder qualified by EN 287, welding process qualified by EN 288, as TIS request). The total deformation and Von Mises equivalent stress analysis have been executed with FEM: the figure 29 shows the calculation environment.

40 ATLAS Project Document No: Page: 40 of 51 The total load (Q 1 = 765 N ) has been subdivided into six equal forces, each of N, applied to the six support plates. The dead load of the Extension has been applied as remote force of 125 N, in barycentric position. The coordinates of the remote force displayed are relative to the local coordinate system represented in the box of the figure 29, with the zero point coincident to the middle of the external edge of the Extension: x b1 coordinate of the remote force correspond to the position of the longitudinal axis of symmetry (Extension width / 2 = 580 / 2 = 290 mm). y b1 coordinate (578.4 mm) refers to the previous calculation with solid modeler NX3, specified at paragraph 8.1, reported to the local coordinate system (y b1 = total length of Extension frame barycenter distance from fixed support = = mm). A Fixed support constraint has been applied on contact surface of the two connection plates to the Structural Base. Figure 29 - STRUCTURAL BASE EXTENSION : CALCULATION ENVIRONMENT Figure 30 shows the total deformation analysis, where the Extension maximum deformation (δ max ) is: δ max = 1.7 mm.

41 ATLAS Project Document No: Page: 41 of 51 Figura 30 - STRUCTURAL BASE EXTENSION: TOTAL DEFORMATION ANALYSIS Figure 31 shows the results of Von Mises equivalent stress analysis (1 MPa = 1 N/mm²). The equivalent stress maximum value is: σ max = 61.8 N/mm². σ max = 61.8 N/mm² < σ adm = 115 N/mm² Figure 31 - STRUCTURAL BASE EXTENSION: EQUIVALENT STRESS ANALYSIS

42 ATLAS Project Document No: Page: 42 of STAY BOLTS The Extension is fixed to the Structural Base altogether by eight threaded M12 stay bolts, of two different length (n.4 Item 4, n.4 Item 5 - drawing ATL-DST Rev.0), inserted in passing holes through the hollow shapes, and locked with double nut (Item 6) and spring washer (Item 7), as shown in figure 32. The characteristics of the stay bolts are following: Bolt class: UNI EN 20898/1 Yield Stress (Nominal R p0,2 ): f y = 900 N/mm² Admissible tensile tension: σ b,adm = f y / k = 900 / 2.4 = 375 N/mm² Admissible shear tension τ b,adm = σ b,adm / 3 = 217 N/mm² Diameter: d = 12 mm Thread: M12 pitch 1.75 mm Thread kern diameter: d n = 9.85 mm Resisting Section Area : A res = 76 mm² Young s Modulus: E = N/mm² Figure 32 EXTENSION FIXED BY STAY BOLTS For resistance verification of stay bolts are considered both: The moment M due to the extension weight and supported load. The axial stress N s and torque T s1 due to the nut tightening. The forces distribution is shown in figure 33 (ref. paragraph 9.3.1): the load supported by the Extension (Q 1 = 765 N) is subdivided into six forces of equal intensity: Q 6 = N, obtaining the load for each support plate.

43 ATLAS Project Document No: Page: 43 of 51 The dead load of the Extension, Q E = 125 N, is applied in barycentric position, at distance y b = mm from the connecting plates with the Structural Base (see paragraph 8.1). Figure 33 EXTENSION FORCES DIAGRAM The moment M, due to the forces of figure 33, related to rotation center O, is: M = 2 Q 6 a + Q E y b + 2 Q 6 (a + i) + 2 Q 6 (a + 2i) = Nmm The stay bolts are positioned on two rows (see figure 33) : The first row is at distance r = 10 mm from O n.4 stay bolts with length l 1 = 150 mm. The second row is at distance R = 70 mm from O n.4 stay bolts with length l 2 = 200 mm. The stay bolts are tensile stressed by the moment M. Elongation L is greater for the stay bolts at distance R from the rotation center O rather than for the stay bolts at distance r (ratio factor: R/r = 7), being the deformation angle the same. Being T 1 the axial stress for stay bolt at distance r, with length l 1 : T 1 = E A res L / l 1 the axial stress T 2, for stay bolt at distance R, with length l 2, is: T 2 = E A res (7 L) / l 2 therefore the ratio factor between them is: T 2 / T 1 = 7 l 1 / l 2 = 5.25 => T 2 = 5.25 T 1 M = n T 1 r + n 5.25 T 1 R => T 1 = M / n (r R ) = 308 N Where : n = 4 stay bolts number for each row

44 ATLAS Project Document No: Page: 44 of 51 The axial stress for each stay bolts of the row at distance R is: T 2 = 5.25 T 1 = 1617 N The stay bolts must realize a friction joint between contact surfaces of Extension connection plates and Structural Base connection plates, in order to avoid arrangements of the joint under load. The minimum vertical force transmitted by friction must be : F f = 6 Q 6 + Q E = 890 N The minimum force transmissible by friction from each stay bolt (V f,o-min ), multiplied for the stay bolts total number n t = 8, refered to contact surfaces between Structural Base and Extension, must be equal to F f : n t V f,o-min = F f = 890 N => V f,o-min = 112 N With reference to Section CNR-UNI 10011/97, V f,o (min) is expressed by: V f,o-min = µ N s,min / γ f Where : µ = 0.3 (estimate) friction factor between the contact surfaces N s,min = minimum axial force in the screw body, due to tightening torque γ f = 1.25 reduction factor => N s,min = V f,o-min γ f / µ = 467 N The minimum tightening torque T s,min of stay bolt must be (ref. Section CNR-UNI 10011/97): T s,min = 0.2 N s,min d = 1121 Nmm 1.1 Nm Where : d = 12 mm stay bolt diameter Being this calculated minimum tightening torque a small value, we need to determine an effective value to be used during assembling. We assume, in first approximation with final verification, that maximum tensile stress in the bolt body (for the stay bolt at distance R from O ), should be 70% of the product σ b,adm A res, calculating the maximum value N s,max of the axial force in the screw body, due to tightening torque: N s,max + T 2 = 0.7 σ b,adm A res => N s,max = 0.7 σ b,adm A res - T 2 = N The maximum tightening torque T s,max result: T s,max = 0.2 N s,max d = Nmm = 44 Nm

45 Final resistance verification of mainly stressed stay bolt: ATLAS Project Document No: Page: 45 of 51 The mean normal tension σ t1, due to T 2 is: σ t1 = T 2 / A res = 21 N/mm² The mean normal tension σ t2, due to N s,max is: σ t2 = N s, max / A res = 241 N/mm² The maximum normal tension (σ max ) is: σ max = σ t1 + σ t2 = 262 N/mm² < σ b,adm = 375 N/mm² The torque in stay bolt body (T s1 ) can be calulated following the indications of par. 14 Mechanical Engineer Handbook (P. Andreini - Hoepli edition): T s1 = N s, max tg (α + φ) (d m / 2) = Nmm Where : α = 2. 9 thread helix mean angle φ = arctg (f 1 / cos θ/2 ) = 9.8 f 1 = 0.15 (estimate) friction factor between stay bolt thread nut thread θ = 60 thread profile angle d m = mm thread mean diameter The maximum tangential tension (τ max ), due to T s1, is: τ max = (16 T s1 ) / π d n ³ = 120 N/mm² < τ b,adm = 217 N/mm² According to section CNR-UNI 10011/97, it should be : (τ max / τ b,adm )² + (σ max / σ b,adm )² 1 Final verification : (τ max / τ b,adm )² + (σ max / σ b,adm )² = 0.8 1

46 ATLAS Project Document No: Page: 46 of REFERENCES [1] Assembling and Testing the Pixel Detector System ATL-IP-ES-0007 [2] Pixel Detector Installation System Description ATL-IP-IP-0002 [3] Pixel Installation Procedure ATL-IP-IP-0003 [4] INNER DETECTOR Interface Parameter and requirements for ID Installation Platform ATL-IC-ES-0008 [5] The Pixel Dummy Support Tube ATL-IP-ES-0107 [6] Metallic Structure of the DST (Dummy Support Tube) v.2 ATL-IP-ED-0215

47 ATLAS Project Document No: Page: 47 of 51 ANNEX A: OTHER MECHANICAL STRUCTURES FOR DST A1 SUPPORT TABLE IN SURFACE The Support Table in Surface (STS) is a mechanical structure for the support and the movement of DST MB in surface (see figure a1-1). Figure a1-1 SUPPORT TABLE IN SURFACE ON WHEELS WITH DST-MB STS is made by structural steel carpentry, with rectangular hollow shapes and plates of several dimensions assembled by means of arc welding with cored electrodes or FCAW (welder qualified by EN 287, welding process qualified by EN 288). STS supports the Structural Base with the DST-MB, and is equipped, alternatively, with: Adjustable feet (see figure a1-2), during Detector test phase in SR-1 clean room. Adjustable feet allow DST-MB axis correct height in order to make the transition of the Pixel Detector from the ITT integration tool. Spring loaded swivel castor wheels and handles (see figure a1-3), for the movements of DST-MB, mainly from the SR-1 Building to the ATLAS cavern access. The STS Working Drawings Set is loaded on EDMS data base in the document ATL-IP-ED-0215.

48 ATLAS Project Document No: Page: 48 of 51 Figure a1-2 SUPPORT TABLE IN SURFACE ON FEET Figure a1-3 SUPPORT TABLE IN SURFACE ON WHEELS The total deformation analysis of STS, under load condition, has been executed by FEM, using a simplified quarter model. Figure a1.4 shows the results of total deformation analysis for STS configuration on feet. Figure a1.5 shows the results of total deformation analysis for STS configuration on wheels.

49 ATLAS Project Document No: Page: 49 of 51 Figure a1-4 STS ON FEET (QUARTER MODEL) TOTAL DEFORMATION ANALYSIS Figure a1-5 STS ON WHEELS (QUARTER MODEL) TOTAL DEFORMATION ANALYSIS

50 ATLAS Project Document No: Page: 50 of 51 A2 SUPPORT STRUCTURE IN PIT The Support Structure in Pit (SSP) is a mechanical structure for the support of the Structural Base with DST MB in Atlas cavern (see figure a2-1). Figure a2-1 SUPPORT STRUCTURE IN PIT WITH DST-MB In the ATLAS cavern, SSP will be supported by an appropriate interface of the CERN (ID Rotation & Alignment Stage), in order to carry out the final installation of the Pixel Detector: the adjustable feet allow the correct positioning of the axis of the DST-MB. Adjustable feet, after height regulation, should be fixed to the ID Rotation & Alignment Stage interface inserting 4 M6 screws in the 4 clamping discs, one for each foot. SSP (see figure a2-2) is made by structural steel carpentry with rectangular hollow shapes and plates of several dimensions assembled by means of arc welding with cored electrodes or FCAW (welder qualified by EN 287, welding process qualified by EN 288). The SSP Working Drawings Set is loaded on EDMS data base in the document ATL-IP-ED The total deformation analysis of SSP, under load condition, has been executed by FEM, using a simplified quarter model. Figure a2-3 shows the results of total deformation analysis for SSP.

51 ATLAS Project Document No: Page: 51 of 51 Figure a2-2 SUPPORT STRUCTURE IN PIT Figure a2-3 SSP QUARTER MODEL TOTAL DEFORMATION ANALYSIS