How does modulus of elasticity in bending differ from standard modulus of elasticity?
I want to know if flexural stress divided by flexural strain is the same as modulus of elasticity in bending? ASTM D790 12.9.1 states that you calculate the modulus of elasticity by drawing a tangent to the steepest initial straight-line portion of the load-deflection curve and use the eq. EB=L3m/4bd3. If the MOE is stress/strain than why use the load deflection curve and the equation to calculate?
Many materials especially plastics have different stress vs strain curves in tension / compression as compared to flexure modulus. This is especially true with plastics. As a result you must calculate the modulus of elasticity for both modes. Many data sheets have both values indicated.
Niel
the MOE in bending is just that. its the ratio of stress to strain during a bending test of a predetermined sample.
the MOE for tensile is the ratio of stress to strain in tension (stretching) of a sample.
its “load vs deflection”
you must apply a load or force to a sample to induce stress upon the cross sectinoal area of that sample.
the deflection is an indication of strain or deformation, whether its axial, lateral, compressive etc….
don’t forget that; MOE or Youngs modulus is only within the propoertional limits of a given material. which is the maximum allowable stress to endure infinate loading.
MOE is a moving target in materials and you have to remember that it will dramatically change based on how the material was made eg. grain reduction due to drawing, cold forming and or heat treatment.
so you could have the same alloy but different MOE depending on what each mandufacture did during the creation of that bar, plate ture…..
