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ν ij is the Poisson ratio that corresponds to a contraction in direction j when an extension is applied in direction i. The Poisson ratio of an orthotropic material is different in each direction (x, y and z). However, the symmetry of the stress and strain tensors implies that not all the six Poisson's ratios in the equation are independent.
where K is the stress intensity factor (with units of stress × length 1/2) and is a dimensionless quantity that varies with the load and geometry. Theoretically, as r goes to 0, the stress σ i j {\displaystyle \sigma _{ij}} goes to ∞ {\displaystyle \infty } resulting in a stress singularity. [ 5 ]
Elastic properties describe the reversible deformation (elastic response) of a material to an applied stress.They are a subset of the material properties that provide a quantitative description of the characteristics of a material, like its strength.
The way the equation is defined won't give you a poisson's ratio of 0.5 for a perfectly incompressible material. It gives a ratio of 2 as defined in the article. Draw a quick before and after square diagram to see what I mean.
The two parameters together constitute a parameterization of the elastic moduli for homogeneous isotropic media, popular in mathematical literature, and are thus related to the other elastic moduli; for instance, the bulk modulus can be expressed as K = λ + 2 / 3 μ.
Siméon Denis Poisson. Poisson's equation is an elliptic partial differential equation of broad utility in theoretical physics.For example, the solution to Poisson's equation is the potential field caused by a given electric charge or mass density distribution; with the potential field known, one can then calculate the corresponding electrostatic or gravitational (force) field.
In probability theory and statistics, the Poisson distribution (/ ˈ p w ɑː s ɒ n /; French pronunciation:) is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time if these events occur with a known constant mean rate and independently of the time since the last event. [1]
The coefficients u i are still found by solving a system of linear equations, but the matrix representing the system is markedly different from that for the ordinary Poisson problem. In general, to each scalar elliptic operator L of order 2 k , there is associated a bilinear form B on the Sobolev space H k , so that the weak formulation of the ...