COE 3001 Lecture 3: 3+Stress+strain+Diagrams

• School: Georgia Tech
• Department: College of Engineering
• Course: COE 3001
• Professor: Thomas Susan

Document Summary

We determine the mechanical properties of materials by performing controlled tests and obtaining force-displacement curves. There are all sorts of tests--tension, compression, torsion, shear, static, and dynamic--but all these tests serve to quantify the mechanical behavior of the material. Let"s consider a simple example of normal strain with axial loading: We can plot the magnitude p of the load against the deformation . But let"s consider a member that has 2a but same l. To achieve the same , we need 2p for both rods to satisfy the same stress condition. The deformation will be 2d because both the ratio of deformation of length of rod the same. It is a measure of deformation per unit length. So, we can plot = versus = to get curve of characteristic properties of material. To obtain this, we convert the force-displacement curves (since these are measurable quantities) into stress-strain curves (because these are only calculable quantities).