ME 421 - Machine Design, Theory and Project

Institution:

Point Park University

Subject:

Description:

The course begins with a review of basic strengths of materials including plane stress, shear stress, stresses due to bending and torsion and the stability of columns. Further work includes the generation of equations for principle stress and maximum shear stresses resulting from the compounding of bending and torsional stresses. The von Mises criterion is presented. Rayleigh's equation for the critical speed of shafts carrying gears is developed and the method is applied to systems having three concentrated loads with two bearings. Bearings might be of the sleeve or spherical roller type. A shaft design project requires that students draw from their knowledge of dynamics and strength of materials to determine the required diameter of a shaft which is subject to bending and torsion and must transmit a specified power using a given safety factor. The critical speed of the system is determined. Stresses are determined for thin walled and thick walled cylinders which are subject to internal pressure. This work is extended to deal with concentric cylinders and shrink-fits. Keys and keyways are designed using maximum shear stress and maximum bearing stress criteria. Belt drive systems are designed with consideration of lifting systems includes those using acme power screws and those using ball screws. Drum brakes, disc brakes and clutches are designed. The course closes with work on proper choice of electric motors for a given application. Prerequisites: MATH 210, ME 102, ME 213, ME 320. Course Objectives Upon successful completion of the course, students will be able to: (1) Find principle stresses and maximum shear stresses for compound stress situations. (2) Apply the von Mises criterion. (3) Determine the critical speed of a shaft under a variety of load and bearing conditions. (4) Find hoop stress in thin walled and thick walled cylinders that are subjected to internal and external pressure. (5) Design shrink fits for power transmission. (6) Design keys and key-ways. (7) Design belt drive systems. (8) Design drum brakes, disc brakes and clutches. (9) Design power screws. (10) Make appropriate electric motor selections. (11) Produce a professional design document which addresses every aspect of the design specifications.

Credits:

4.00

Credit Hours:

Prerequisites:

Corequisites:

Exclusions:

Level:

Instructional Type:

Lecture

Notes:

Additional Information:

Historical Version(s):

Institution Website:

www.pointpark.edu

Phone Number:

(412) 391-4100

Regional Accreditation:

Middle States Association of Colleges and Schools

Calendar System:

Semester

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