Copyright 1997, American Institute of Aeronautics and Astronautics, Inc.

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Antonia Mosley
5 years ago
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2 CHOOSEPLOT (user chooses what

4 The "localbuck(vinson)" margin provides a parallel prediction of what PANDA2 has always computed with analysis type IQUICK=1, that is, local buckling analysis of the panel module segments with use of Eq.(57) in [21] with subsequent "knockdown" as described in Section 8.2 of [14] to account for the effect of transverse shear deformation. For local buckling of the panel skin, the previously (and still) available PANDA2 margins that represent the same phenomenon as "localbuck(vinson)" read: buck.(donl) simp-support local buck... buck.(sand) simp-support local buck... in which the string "DONL" means "Donnell theory" and "SAND" means "Sanders theory".

7 The stresses, <T zl, T^p and T j play a significant role in the stress constraints to be discussed later in the subsection entitled "Additional

10 curvature give rise to tension in the core normal to the face sheets.

11 "sandwichcore tension margin...". IMPLEMENTATION

12 BEGIN Introduce

13 implementation of the "sandwich" capability occur in SUBROUTINE BUCPAN. strain energy in a manner analogous to that done in BUCPAN2 Introduce the elastic foundation modulus term, EFOUND^, into the coefficient a 33 (see Eq. 55f, p.

14 the constraint conditions involving the maximum allowable

15 deformation-induced sandwich core crushing pressure. (See discussion above associated with Eqs.(31) - (33)). SUBROUTINE STRCON was modified to compute x-z and

17 some negative margins, provided that

19 transverse shear deformation is neglected. Since the width/thickness ratio

20 margins remain essentially the same. Those that are significantly affected by the introduction of finite initial face sheet waviness, W 0 / L = 0.001, are the core crushing margin, the x-z ("L-direction") core transverse shear stress margin,

21 which a reasonable level of initial facesheet waviness is present. The results for the final optimum design are listed in Table

24 (bottom facesheet has higher destabilizing resultants than

25 while the work was in progress. Dr. Frank Weiler helped

27 !i

28 5.!i V H da o a S I 1 h ''! i j H H H H H H I p t* *o r- * r* 1 J rt «* H ^# (O I < v> 01 w> H m

31 >ioooooo

32 h ftt **H * ««. H *. H fc H i-4 h rl H I I H H H J«I IJ I I?! S' ah: III HHHHHMHHHHHHMHHHHMH^H I I

34 Seg. 3 (Iseg numbering) Seg.

35 Objective H- 05 (O hi I P< C H H- rt P- 3 H- IS) rt H- o H fl>

36 D eff.stress:matl=1; MID.

37 ff &<D ZZ LU 111 _J _l 99 ; ^^ OCD zz _J _J QQ CM A-'cvT CD CD <D CD O O J?j$ H as «+ ca a a 99 5S ^- ^- 7^^-

38 «- CO 01 m 4) 5 o a) D m 1) O (0 U-J O rt o 4J 3 H a IS) o m H o n) tn U6JS9Q O-Q ro- 2200

39 Design Parameters "d H- W O H H- O O Hi cr o> *; oo o oh 01 to 3* M H O pi h ' tf[ rt 0 rt 3 H- 9) O H O OH, (D < O PJ O O Hi ID H O H 3 H- O> (D

40 tc(2 )(SKN):thickness x10'

Nomenclature. Length of the panel between the supports. Width of the panel between the supports/ width of the beam

Nomenclature. Length of the panel between the supports. Width of the panel between the supports/ width of the beam omenclature a b c f h Length of the panel between the supports Width of the panel between the supports/ width of the beam Sandwich beam/ panel core thickness Thickness of the panel face sheet Sandwich