ENGR 225 Section

Saint-Venant’s Principle When loading is applied at a point on a body, it tends to create a stress distribution that becomes more uniform at regions removed from the point of application.

In the uniform deformation region  = P/A What about regions near load and support? Section 4.7

Single concentrated load P  = P/A Average Normal Strain in the bar  =  L / L Also  = E  So, P/A = E (  L / L) Deformation  L = PL/AE Elastic Deformation of an Axially Loaded Member

Multiple loads, concentrated and distributed

Displacement Equation

Constant Load

Sign Convention A force or displacement is considered to be positive if they cause tension or elongation. A force or displacement is considered to be negative if they cause compression or contraction.

Problem 4-2: Determine the displacement of A with respect to D.

Problem 4-24: Show that the displacement of the end of the rod due to the load is δ=PL/(πEr 1 r 2 ). Neglect the weight of the material.