WORCESTER POLYTECHNIC INSTITUTE MECHANICAL ENGINEERING DEPARTMENT DESIGN OF MACHINE ELEMENTS ME-3320, B 2018 Lecture 04 October 2018
Office hours: Announcements (also in the website of our course) Prof. Furlong, M to Th, 10:00-10:50 AM or by appointment (HL-152) TA: By appointment MathCad Help sessions (attendance will be recorded): Mondays 4:00-4:50 pm in HL-230 Design Project: list of members (due Today) Exams: please review website for details
Topics for today Introduction to MathCAD: step functions Shear, moment, torsion diagrams: examples w/singularity functions Progress report specifications Questions to ask (design project): e.g., geometry of the designs, location of bearings?, distance between bearings?, types of fixtures, materials, height of the tower, load types and boundary conditions, etc.
Internal forces and moments Shear, Normal, and Bending moments Internal forces (determination of shear and moment diagrams) Component FBD Sections Internal: moments, shear, and normal forces at point C
Internal forces and moments Shear, Normal, and Bending moments Section at point C z y x
Shear and bending-moment diagrams A suspended bar supports a 600-lb engine. Plot the shear and moment diagrams for the bar. Method of sections: plot using step functions + MathCad 1.5 ft 1.5 ft
Shear and bending-moment diagrams Method of sections: plot using step functions + MathCad ME-3320: more details in Thursday s help session
Shear and bending-moment diagrams Singularity functions
Shear and bending-moment diagrams Singularity functions
Shear and bending-moment diagrams Singularity functions Loading function: Shear function: Moment function: q(x) V ( x) M ( x) q( x) dx V ( x) dx
Shear and bending-moment diagrams Singularity functions: in-class examples (loading functions)
Shear and bending-moment diagrams Singularity functions: in-class examples (loading functions)
Shear and bending-moment diagrams Singularity functions: example E1 Determine and plot the shear and moment functions for the simply supported beam shown:
Shear and bending-moment diagrams Singularity functions: example E1 - MathCad
Shear and bending-moment diagrams Singularity functions: example E2 Determine and plot the shear and moment functions for the cantilever beam shown:
Shear and bending-moment diagrams Singularity functions: example E2 - MathCad
Shear and bending-moment diagrams Singularity functions: example E3 Determine and plot the shear and moment functions for the beam shown:
Shear and bending-moment diagrams Singularity functions: example E3 - MathCad
Design project: movie clip Discussions and design tasks Source: http://www.mecal.nl
Design project for this course: objectives Do note: this is an unstructured, engineering, project! (e.g., design teams must fully define design parameters, constraints, etc.) Detailed design of the main shaft and selection of corresponding bearings and fixtures of a Vestas V52-850 kw wind turbine Detailed design of the tower of a Vestas V52-850 kw wind turbine
Design project: Schedule (refer to our entire course outline in course webpage) o Monday, November 05. Progress Report #1 Background research. Design constrains. FBD s. Assumptions o Monday, November 19. Progress Report #2 Full static and dynamic analysis o Monday, December 03. Progress Report #3 Full stress analysis. Preliminary designs o Friday, December 14. Final Report Final proposed designs and detail report
Design project: Report Specifications ME-3320, B 18. DESIGN OF MACHINE ELEMENTS 26 October 2018 1000-2000 words
Design project Discussions and tasks to be performed Your first report must include: (Consider visiting an actual site) o Your design objectives & constrains, functional specs (specific to your designs). o Introduction and Background research on Wind Turbines (in general): e.g., historical perspectives, materials used, typical dimensions, efficiencies, design configurations/specifications, operation, etc. (as discussed in class) o FBD s (specific to your designs): identification of geometrical configurations, loading conditions (static and dynamic), assumptions. o Remember: shear, bending, torsion diagrams (main shaft + tower) are next - leave this task as part of next report. Nacelle of a wind turbine: front view Hub of a lowspeed shaft Former ME3320 students Source: http://www.mecal.nl Location: Danforth, Maine
Design project Discussions and tasks to be performed Identify geometrical configurations & loading conditions (specific to your designs.) Example mechanical configuration Source: http://www.nordex-online.com Source: http://www.nordex-online.com Example: low-speed shaft configuration Source: ZENKUNG Co., China
Design project Discussions and tasks to be performed Identify geometrical configurations & loading conditions (specific to your designs.) Example shaft /generator configuration Source: Boston Science Museum
Reading assignment Chapters 1, 3, and 9 of textbook Review notes and text: ES-2501, ES-2502 Author s: 3-5A, 3-5B, 3-6 Homework assignment Solve: 1-7, 1-8(optional), 3-23(c,h), 3-24(c,h)