# Finite Element Method Questions and Answers – Two Dimensional Problems – Orthotropic Materials

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This set of Finite Element Method Multiple Choice Questions & Answers (MCQs) focuses on “Two Dimensional Problems – Orthotropic Materials”.

1. Give an example of orthotropic material?
a) Topaz
b) Aluminum
c) Barium
d) Sodium

Explanation: Orthotropic materials have material properties that differ along three mutually orthogonal two fold axis of rotational symmetry. They are a subset of anisotropic materials, because their properties change when measured from different directions.

2. Unidirectional fiber- reinforced composites also exhibit _______ behavior.
a) Isotropic
b) Orthotropic
c) Material
d) Unidirection composite

Explanation: Orthotropic materials have material properties that differ along three mutually orthogonal two fold axis of rotational symmetry. They are a subset of anisotropic materials, because their properties change when measured from different directions.

3. Orthotropic planes have ____ mutually perpendicular planes of elastic symmetry.
a) One
b) Two
c) Three
d) Four

Explanation: Orthotropic materials have material properties that differ along three mutually orthogonal two fold axis of rotational symmetry. Wood may also consider to be orthotropic. These materials have three mutually perpendicular planes.

4. The principal material axes that are normal to the _______
a) Co-ordinates
b) Number of nodes
c) Principal axes
d) Plane of symmetry

Explanation: Orthotropic materials are a subset of anisotropic; their properties depend upon the direction in which they are measured. Orthotropic materials have three planes of symmetry. That is normal to principal material axes.

5. v12 indicates that the poisson’s ratio that characterizes the decrease in ______ during tension applied in ______
a) 2- direction and 1- direction
b) 2- direction and 3- direction
c) 1- direction and 2- direction
d) 2- direction and 4- direction

Explanation: Poisson’s ratio is the ratio of transverse contraction strain to longitudinal extension strain in the direction of stretching force. Tensile deformation is considered positive and compressive deformation is considered negative.

6. Unidirectional composites are stacked at different fiber orientations to form a ______
a) Laminate
b) Orthotropic material
c) Isotropic material
d) Anisotropic material

Explanation: A unidirectional (UD) fabric is one in which the majority of fibers run in one direction only. A laminate is a tough material that is made by sticking together two or more layers of a particular substance.

7. When an orthotropic plate is loaded parallel to its material axes, it results only _____
a) Shear strains
b) Normal strains
c) Parallel strains
d) Uniform strains

Explanation: Orthotropic materials are a subset of anisotropic; their properties depend upon the direction in which they are measured. When an orthotropic plate is loaded parallel to its material axes, it results normal strains.

8. When the stresses are determined in an orthotropic material, then they are used to determine ____
a) Strains
b) Deformation
c) Factor of safety

Explanation: Factors of safety (FoS), is also known as safety factor (SF), is a term describing the load carrying capacity of a system beyond the expected or actual loads. Essentially, the factor of safety is how much stronger the system is than it needs to be for an intended load. After determining the stresses in orthotropic materials by using an appropriate failure theory we can find factor of safety.

9. Stress- strain law defined as ______
a) σ=D(ε-ε0)
b) σ=D
c) σ=Dε
d) σ=Dε0

Explanation: The relationship between the stress and strain that a particular material displays is known as that particular material’s stress–strain curve. It is unique for each material and is found by recording the amount of deformation (strain) at distinct intervals of tensile or compressive loading (stress).

10. E1 value of Balsa wood is ___
a) 0.125*106psi
b) 12.04*106psi
c) 23.06*106psi
d) 7.50*106psi 