Stress (mechanics)

Stress is the internal force per unit area transmitted through a material when external forces act on it. It describes both the magnitude and direction of forces across an imagined surface inside the material.

Cauchy stress tensor: A second-order tensor describing traction on every plane through a point in a continuum. It collects the normal and shear stresses acting on all possible internal planes.
Force: An interaction that changes or tends to change an object's motion or shape. External forces create the internal interactions measured as stress.
Yield strength: The stress at which a material begins to deform plastically under a specified test. Comparing working stress with yield strength helps prevent permanent deformation.
Pressure: A scalar measure of isotropic compressive force per unit area in a fluid or at a boundary. Pressure is direction-independent, unlike the full stress state in a solid.
Normal stress: The component of stress perpendicular to a surface. It distinguishes tension and compression from forces acting along the surface.
Area: A measure of the size of a two-dimensional surface. Stress divides force by the area across which it is transmitted.
Ultimate tensile strength: The maximum tensile stress a material reaches in a standard tensile test. It marks a key limit in assessing tensile capacity.
Hydrostatic stress: The isotropic part of a stress state, equal in all directions at a point. It isolates the uniform compression or tension from shape-changing stress.
Shear stress: The component of stress parallel to a surface. It describes the sliding action that accompanies many loaded materials.
Strain (mechanics): A measure of deformation expressed as relative change in length, angle, or volume. Strain describes the resulting change in shape, not the internal force intensity.

Linked from 39 pages