Strength refers to the ability of a material to resist plastic deformation and fracture under load. Due to the various modes of action of loads such as tension, compression, bending, and shear, strength is also divided into tensile strength, compressive strength, flexural strength, shear strength, etc. There is often a certain correlation between various strengths, and tensile strength is generally used as the most basic strength indicator in use.
Plasticity refers to the ability of a material to undergo permanent deformation under load without being destroyed.
Stiffness refers to the ability of a material to resist elastic deformation under load.
Tensile strength, plasticity, and stiffness are determined through static tensile testing. During the experiment, slowly apply a load to both ends of the cylindrical or plate-shaped specimen on the stretching machine, causing the specimen to elongate along the axial direction under axial tension until it is pulled apart.
This type of externally applied load is called an external force; Due to external forces, an object generates a force inside that resists external forces, which is called internal force. The strength, plasticity, and stiffness of the material can be determined based on the load and deformation experienced by the specimen during the tensile process.