Tensile strength refers to a material’s ability to withstand pulling forces on the material. In measuring tensile strength, dog-boned shaped specimens of specific size and cross-sectional area are pulled apart until they break. Stress is the load per unit area in pounds per square inch that is applied. Strain is the stretched portion or elongation measured in inches per inch.
Machines capable of applying extremely high-tension loads are required to run tensile tests. Therefore most samples are reduced to a 0.2 square inch cross-sectional area for testing. Tensile testing machines apply a smooth steady pressure measured in pounds or kilograms. A needle shows the amount of pressure that is being applied. After the maximum tension load the specimen can withstand is reached, the pressure begins to reduce as the specimen begins to stretch from the tension force. The highest travel of the needle indicates tensile strength.
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