Examples of stress in the following topics:
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- The ratio of force to area $\frac{F}{A}$ is called stress and the ratio of change in length to length $\frac{\Delta L}{L}$ is called the strain.
- Deformations come in several types: changes in length (tension and compression), sideways shear (stress), and changes in volume.
- The ratio of force to area $\frac{F}{A}$ is called stress and the ratio of change in length to length $\frac{\Delta L}{L}$ is called the strain.
- Stress and strain are related to each other by a constant called Young's Modulus or the elastic modulus which varies depending on the material.
- Using Young's Modulus the relation between stress and strain is given by: $\text{stress} = Y\cdot\text{strain}$.
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- A fluid is a substance that continually deforms (flows) under an applied shear stress.
- A fluid is a substance that continually deforms (flows) under an applied shear stress.
- Solids can be subjected to shear stresses, and normal stresses—both compressive and tensile.
- In contrast, ideal fluids can only be subjected to normal, compressive stress (called pressure).
- Real fluids display viscosity and so are capable of being subjected to low levels of shear stress.
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- Thermal stress is created when a change in size or volume is constrained due to a change in temperature.
- Thermal stress is created by thermal expansion or contraction.
- Thermal stress can be destructive, such as when expanding gasoline ruptures a tank.
- Forces and pressures created by thermal stress can be quite large.
- Another example of thermal stress is found in the mouth.
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- Elasticity is a measure of how much an object deforms (strain) when a given stress (force) is applied.
- Stress is a measure of the force put on the object over the area.
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- Looking back at section on Angular Momentum Transport, we find that stress has units of angular momentum per unit time per unit volume or erg cm$^{-3}$ in cgs units; therefore, it is quite natural to assume that the stress is proportional to the pressure $f_\phi = \alpha P$.
- We know that the stress is given by
- We can combine the $\alpha$-stress with the angular momentum transport equation to give
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- The viscous torque is the product of the viscous stress in the tangential direction, the area upon which the stress acts (the half-height of the disk is $h$) and the radius.
- The viscous stress is proportional to the viscosity and the angular velocity gradient,
- Both the previous equations give the stress.
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- They span large areas by resolving forces into compressive stresses and eliminating tensile stresses (referred to as arch action).
- Because it is subject to additional internal stress caused by thermal expansion and contraction, this type of arch is considered to be statically indeterminate.
- Because the structure is pinned between the two base connections, which can result in additional stresses, the two-hinged arch is also statically indeterminate, although not to the degree of the fixed arch.
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- Fracture strength, also known as breaking strength, is the stress at which a specimen fails via fracture.
- This is usually determined for a given specimen by a tensile test, which charts the stress-strain curve .
- The bones in different parts of the body serve different structural functions and are prone to different stresses.
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- Mathematically, viscosity is a proportionality constant relating an applied shear stress to the resulting shear velocity and is given, along with a representative diagram, (see ).
- As shown, when a force is applied to a fluid, creating a shear stress, the fluid will undergo a certain displacement.
- Different fluids exhibit different viscous behavior yet, in this analysis, only Newtonian fluids (fluids with constant velocity independent of applied shear stress) will be considered.
- A proportionality constant relating an applied shear stress to the resulting shear velocity.
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