Stress (mechanics)

In continuum mechanics, stress is a physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other, while strain is the measure of the deformation of the material. For example, when a solid vertical bar is supporting a weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each particle gets pushed against by all the surrounding particles. The container walls and the pressure-inducing surface (such as a piston) push against them in (Newtonian) reaction. These macroscopic forces are actually the average of a very large number of intermolecular forces and collisions between the particles in those molecules.

Strain inside a material may arise by various mechanisms, such as stress as applied by external forces to the bulk material (like gravity) or to its surface (like contact forces, external pressure, or friction). Any strain (deformation) of a solid material generates an internal elastic stress, analogous to the reaction force of a spring, that tends to restore the material to its original non-deformed state. In liquids and gases, only deformations that change the volume generate persistent elastic stress. However, if the deformation is gradually changing with time, even in fluids there will usually be some viscous stress, opposing that change. Elastic and viscous stresses are usually combined under the name mechanical stress.

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Latest News for: tensile stress

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Fortunately, igus® was up to the challenge ... About the eWolf Tugboat ... In this application, the e-dispenser included several igus® core products, many of which had to be modified because of the high loads and tensile stresses involved ... ....

Secure, Scalable Fiber Deployment: Innovations in Anchor Clamps and Breakout Cables for Harsh Environments

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When paired with breakout cables, which provide fiber separation and routing within complex network topologies, they allow service providers to manage multiple connections with reduced risk of signal degradation or physical stress.

Asymmetric bending boundary layer: The λ-test

PNAS 13 Mar 2025
... of slender structures can be neglected under large tensile stresses.
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