The document discusses the definitions of isotropy, anisotropy, and orthotropy with regards to engineering materials, providing examples like glass and metals for isotropic materials, wood and composites for anisotropic materials, and wood as an orthotropic material. It also outlines the three main types of finite element analysis (FEA) elements and touches on common errors encountered during FEA. Additionally, it raises a question about the significance of a persistent fringe pattern after removing the load in a photoelastic investigation.

1. Discuss and define Isotropy. Anisotropy and Orthotropy with regards to engineering materials.
Regarding Finite Element Analysis: List the three main types of elements and explain how to
choose elements? Common sources of errors in FEA? After conducting a photoelastic
investigation of a sample, you remove the load and notice that a fringe pattern still exists. What
could this mean?
Solution
(i)
Isotropy is the property of the material in which the physical properties of a substance are
independent of the direction of measurement. Glass and metals are examples of isotropic
materials.
Anisotropy is the property of the material in which the physical properties of a substance varies
with the change in direction. Wood and Composites are examples of anisotropic materials.
Orthotropy is the property of the material in which the physical properties of a substance change
when measured from different directions. The properties differ along three mutually orthogonal
twofold axes of rotational symmetry. Wood is an example of orthotropic materials.
(ii)
(a )The three main elements in FEA are -