Final answer:
The ultimate tensile stress is the maximum stress a material can withstand during stretching, and the breaking stress is the stress at which the material fractures. These are graphically represented on a stress-strain diagram, with the ultimate tensile stress at the peak and breaking stress where the curve ends.
Step-by-step explanation:
The ultimate tensile stress is defined as the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract. The breaking stress, also known as the ultimate stress, is the value of stress at the fracture point, where the material actually breaks apart. On a stress-strain diagram, the ultimate tensile stress is represented at the highest point on the curve before it starts to go down, indicating material failure. The breaking stress is found at the point where the curve abruptly ends because the material has fractured.
Tensile strain is the elongation of a material under tensile stress, measured as the fractional change in length. The stress-strain diagram graphically shows the relationship between stress and strain and characterizes a material's response to tensile stress. The elastic modulus, or Young's modulus, describes the material's response in the linear (elastic) region of the stress-strain curve.
The behavior of materials under different stresses and strains is crucial for engineering and construction applications, where the tensile strength and breaking stress inform about the durability and safety of materials used in structures.