Orthotropic Material Properties

Materials are considered to be orthotropic if the properties depend on the direction. To properly use an orthotropic material, the material axes must be defined in the Element Definition dialog. All the structural element types except trusses, beams, tetrahedrals and composites support orthotropic material models. The orthotropic material properties are listed below. Depending on the element type, analysis type and loads, not all the material properties may be required. In addition to these properties, it may be necessary to define some isotropic material properties.

The modulus of elasticity for local axis 1 (E1) is the slope of the stress versus strain curve of local axis n of a material until the proportionality limit. This is also referred to as the Young's modulus of local axis 1. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The modulus of elasticity for local axis 2 (E2) is the slope of the stress versus strain curve of local axis s of a material until the proportionality limit. This is also referred to as the Young's modulus of local axis 2. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The modulus of elasticity for local axis 3 (E3) is the slope of the stress versus strain curve of local axis t of a material until the proportionality limit. This is also referred to as the Young's modulus of local axis 3. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The Poisson's ratio relative for local plane 12 (Major) (ν12) is found by taking the negative lateral strain in the local plane 12 and dividing it by the axial strain in the direction normal to the local plane 12 for an axially loaded member. Typical values for Poisson's ratio range from 0.0 to 0.5. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The Poisson's ratio relative for local plane 13 (Major) (ν13) is found by taking the negative lateral strain in the local plane 13 and dividing it by the axial strain in the direction normal to the local plane 13 for an axially loaded member. Typical values for Poisson's ratio range from 0.0 to 0.5. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The Poisson's ratio relative for local plane 23 (Major) (ν23) is found by taking the negative lateral strain in the local plane 23 and dividing it by the axial strain in the direction normal to the local plane 23 for an axially loaded member. Typical values for Poisson's ratio range from 0.0 to 0.5. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The shear modulus of elasticity of local plane 12 (G12) is the slope of the shear stress versus shear strain of plane 12 of a material until the proportionality limit. This is also referred to as the modulus of rigidity. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The shear modulus of elasticity of local plane 13 (G13) is the slope of the shear stress versus shear strain of plane 13 of a material until the proportionality limit. This is also referred to as the modulus of rigidity. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The shear modulus of elasticity of local plane 23 (G23) is the slope of the shear stress versus shear strain of plane 23 of a material until the proportionality limit. This is also referred to as the modulus of rigidity. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses.

The thermal coefficient of expansion for local axis 1 (Alpha 1) is a property based on the contraction and expansion of the material. This coefficient is needed to do a thermal stress analysis. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses that contain thermal loads. 

The thermal coefficient of expansion for local axis 2 (Alpha 2) is a property based on the contraction and expansion of the material. This coefficient is needed to do a thermal stress analysis. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses that contain thermal loads.

The thermal coefficient of expansion for local axis 3 (Alpha 3) is a property based on the contraction and expansion of the material. This coefficient is needed to do a thermal stress analysis. This property is applicable to all structural element types that support orthotropic material models and is required for all structural analyses that contain thermal loads.