Concrete Test Correct & Answers

Define "strength" for a material - ANSWERStrength is the ability to resist/carry a load applied from/to the material. The types of loading: tension, compression, shear, blending/flexure. Compare and contrast engineering and true stress. Calculate both. - ANSWEREngineering stress calculates force over original cross area where as true stress would be over the current cross area. The reason why we have engineering stress is because sometimes the difference is too small to care or it's too hard to measure the difference under the experiment. Compare and contrast engineering and true strain. Calculate both - ANSWEREngineering strain calculates the difference of lengths divided by the original, where as true strain divides it by the current length Define modulus. Calculate modulus for linear and nonlinear elastic material - ANSWERModulus is the relationship between stress and strain. It provides a measure of stiffness/resistance it deformats. For linear elastic material, it remains it can undergo small deformations. Nonlinear elastic material can undergo large deformations like rubbers Define and calculate Poisson's Ratio - ANSWERPoisson's Ratio is defined as negative lateral strain (x or z) over axial strain (y). When a specimen is stretched longitudinally and contracts transversely due to Poisson effects, its volume will generally increase. When Poisson's ratio equals 0.5, the volume remains constant (example rubber). Ratio for metals is 0.25-0.35 and concrete is 0.15-0.20.