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The yield strength or yield stress is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing ...
In any case, the parameters would be related to the test subjects and the levels of the stress factors being tested. As a simplified example, consider a test object with a life distribution that roughly matches a normal distribution. Tests at various stress levels would yield different values for the mean and standard deviation of the distribution.
Figure 1: The yield stress of an ordered material depends on the square root of the number of dislocations present. Increase in the number of dislocations is a quantification of work hardening. Plastic deformation occurs as a consequence of work being done on a material; energy is added to the material.
In the scan images, the good weld appeared as a uniform line. The defective welds exhibited various discontinuities and a non-uniform appearance. Mechanical testing of the welds showed a marked decrease in properties, with reductions in the yield stress of one-third to one-half the value of the good weld.
Figure 1: View of Drucker–Prager yield surface in 3D space of principal stresses for =, = The Drucker–Prager yield criterion [1] is a pressure-dependent model for determining whether a material has failed or undergone plastic yielding. The criterion was introduced to deal with the plastic deformation of soils.
A yield criterion often expressed as yield surface, or yield locus, is a hypothesis concerning the limit of elasticity under any combination of stresses. There are two interpretations of yield criterion: one is purely mathematical in taking a statistical approach while other models attempt to provide a justification based on established ...
The quadratic Hill yield criterion [1] has the form : + + + + + = . Here F, G, H, L, M, N are constants that have to be determined experimentally and are the stresses. The quadratic Hill yield criterion depends only on the deviatoric stresses and is pressure independent.
Fine slip is defined as a small amount of slip occurring on a large number of planes. Conversely, coarse slip is a large amount of slip on few planes. The yield stress is determined by the creation of dislocations and their resistance to motion. [26] After yielding, a neck is formed in the amorphous region and propagates down the sample length.