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STRENGTH OF MATERIALS
Mechanics of materials, also called strength of materials is a subject which deals with the behavior of objects withstanding stresses and strains
The study of strength of materials often refers to various methods of calculating stresses in structural members, such as beams, columns and shafts. The methods employed to predict the response of a structure under loading and its susceptibility to various failure modes may take into account various properties of the materials other than material yield strength and ultimate strength; for example, failure by buckling is dependent on material stiffness and thus Young's Modulus.
STRENGTH TERMS
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The Various topics covered are as follows :
- Yield Strength is the lowest stress that produces a permanent deformation in a material. In some materials, like aluminum alloys, the point of yielding is difficult to identify, thus it is usually defined as the stress required to cause 0.2% plastic strain. This is called a 0.2% proof stress.
- Compressive Strength is a limit state of compressive stress that leads to failure in the manner of ductile failure (infinite theoretical yield) or brittle failure (rupture as the result of crack propagation, or sliding along a weak plane ).
- Tensile Strength or ultimate tensile strength is a limit state of tensile stress that leads to tensile failure in the manner of ductile failure (yield as the first stage of that failure, some hardening in the second stage and breakage after a possible "neck" formation) or brittle failure (sudden breaking in two or more pieces at a low stress state). Tensile strength can be quoted as either true stress or engineering stress.
- Fatigue Strength is a measure of the strength of a material or a component under cyclic loading and is usually more difficult to assess than the static strength measures. Fatigue strength is quoted as stress amplitude or stress range, usually at zero mean stress, along with the number of cycles to failure under that condition of stress.
- Impact Strength, is the capability of the material to withstand a suddenly applied load and is expressed in terms of energy. Often measured with the Izod Impact Test or Charpy Impact Test, both of which measure the impact energy required to fracture a sample. Volume, modulus of elasticity, distribution of forces, and yield strength effect the impact strength of a material. In order for a material or object to have a higher impact strength the stresses must be distributed evenly throughout the object. It also must have a large volume with a low modulus of elasticity and a high material yield strength
The Various topics covered are as follows :