1, defined and notation
Tensile strength (tensile strength)
before the specimen pulled off withstand the maximum nominal tensile stress.
Tensile strength is a uniform plastic deformation of a metal of transition to a local plastic deformation threshold concentration, the metal is the maximum carrying capacity under static stretching conditions. For the plastic material, which material is uniformly characterized by the maximum plastic deformation resistance, tensile specimens before subjected to the maximum tensile stress, the deformation is uniform, but then beyond, metal began to necking, i.e., to produce concentrated deformation; for no ( or very small) plastically deformed uniformly brittle material, it reflects the fracture resistance of the material. Symbol RM, units of MPA.
during the tensile specimens, after the material into the reinforcing phase with the yield phase transverse cross-sectional dimension significantly reduced pull-off of the maximum force (Fb), divided by the specimen original cross-sectional area (So ) the resulting stress (σ), called the tensile strength or ultimate strength (σb), in units of N / mm2 (MPa). It represents the maximum capacity of the metal material to resist damage under tension. The formula is:
σ = Fb / So
of the formula: maximum force Fb– pull-off specimen is subjected, N (Newton); So – the original specimen cross-sectional area, mm2.
Tensile strength (Rm) means the maximum stress a material subjected to before the pull-off. When the steel yield to a certain extent, due to the rearrangement grain interior, its ability to resist deformation increase again, this time the deformation has developed rapidly, but only as to improve the stress is increased until the stress reaches a maximum value. Thereafter, the ability of steel to resist deformation significantly reduced, and large plastic deformation occurs at the weakest point, where the specimen quickly narrow section necking phenomenon, until fracture failure. Steel before being drawn by the maximum stress value is called the breaking strength or ultimate tensile strength.
Unit: kg / mm2 (kgf withstand basis)
Tensile strength: Tensile strength
Tensile strength = Eh, where E is Young’s modulus, h is the thickness of the material [1.23] Currently tensile strength was measured more common method is to use universal testing machine to be measured tensile / compressive strength material!
2, tensioned membrane tensile strength
membranes under the influence of pure tensile force, without break can withstand the maximum load and the stretching ratio by the width of the membrane, usually N / 5cm represented. It is divided into the warp and weft tensile strength. Warp tensile strength
Tensile strength when stretched membrane in the warp direction. Weft tensile strength
Tensile strength when stretched membrane in the weft direction.