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Cavitation (elastomers)
Cavitation is the unstable unhindered expansion of a microscopic void in a solid elastomer under the action of tensile hydrostatic stresses. This can occur whenever the hydrostatic tension exceeds 5/6 of Young's modulus Young's modulus E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied leng .... The cavitation phenomenon may manifest in any of the following situations: * imposed hydrostatic tensile stress acting on a pre-existing void * void pressurization due to gases that are generated due to chemical action (as in volatilization of low-molecular weight waxes or oils: 'blowpoint' for insufficiently cured rubber, or 'thermal blowout' for systems operating at very high temperature) * void pressurization due to gases that come out of solution (as in gases dissolved at high pressure) References Rubber ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Instability
Elastic instability is a form of instability occurring in elastic systems, such as buckling of beams and plates subject to large compressive loads. There are a lot of ways to study this kind of instability. One of them is to use the method of incremental deformations based on superposing a small perturbation on an equilibrium solution. Single degree of freedom-systems Consider as a simple example a rigid beam of length ''L'', hinged in one end and free in the other, and having an angular spring attached to the hinged end. The beam is loaded in the free end by a force ''F'' acting in the compressive axial direction of the beam, see the figure to the right. Moment equilibrium condition Assuming a clockwise angular deflection \theta, the clockwise moment exerted by the force becomes M_F = F L \sin\theta. The moment equilibrium equation is given by F L \sin \theta = k_\theta \theta where k_\theta is the spring constant of the angular spring (Nm/radian). Assuming \theta is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Young's Modulus
Young's modulus E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied lengthwise. It quantifies the relationship between tensile/compressive stress \sigma (force per unit area) and axial strain \varepsilon (proportional deformation) in the linear elastic region of a material and is determined using the formula: E = \frac Young's moduli are typically so large that they are expressed not in pascals but in gigapascals (GPa). Example: * Silly Putty (increasing pressure: length increases quickly, meaning tiny E) * Aluminum (increasing pressure: length increases slowly, meaning high E) Higher Young's modulus corresponds to greater (lengthwise) stiffness. Although Young's modulus is named after the 19th-century British scientist Thomas Young, the concept was developed in 1727 by Leonhard Euler. The first experime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
