3. Stresses in Machine Elements Lecture Number – 3.2 Prof. Dr. C. S. Pathak Department of Mechanical Engineering Sinhgad College of Engineering, Pune Strength of Materials

Agenda 1 Illustrative Numerical 1 Workout Example Strength of Materials

Illustrative Example The largest allowable stresses for the cast iron link are 30 MPa in tension and 90 MPa in compression. Determine the largest force P which can be applied to the link. Strength of Materials

SOLUTION Determine an equivalent centric load and bending moment. Superpose the stress due to a centric load and the stress due to bending. Evaluate the critical loads for the allowable tensile and compressive stresses. The largest allowable load is the smallest of the two critical loads. Strength of Materials

Solution Strength of Materials

Determine an equivalent centric and bending loads. Strength of Materials

Superpose stresses due to centric and bending loads Strength of Materials

Evaluate critical loads for allowable stresses. The largest allowable load Strength of Materials

Workout Example For the beam and loading shown, determine the maximum normal stress due to bending. Strength of Materials

SOLUTION Treating the entire beam as a rigid body, determine the reaction forces Section the beam at points near supports and load application points. Apply equilibrium analyses on resulting free-bodies to determine bending couples Identify the maximum bending-moment. Apply the elastic flexure formulas to determine the corresponding maximum normal stress. Strength of Materials

SFD and BMD Strength of Materials

Solution Strength of Materials

I Section A moment of 100 kN-m is applied to 2 m length beam of I section as shown in figure, find the maximum bending stress and draw the stress distribution diagram. Strength of Materials

Solution Strength of Materials