Static Structural Analysis

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  • Last Post 30 April 2018
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rrdbes posted this 29 April 2018

Hi I am inputing a new Engineering Material in Ansys workbench. I wonder what could be the required mechanical properties that i'll be needing to test for compressive stress, tensile stress, deflection,  and deformation. Thanks!

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peteroznewman posted this 29 April 2018

The simplest and most common Static Structural model can be solved with just the Isotropic Elasticity material model, which requires two property values: Young's Modulus and Poisson's Ratio. With those two values, you can calculate stress and deformation. This is only appropriate if the material you want to simulate is isotropic with linear elastic behavior. There are other material models for other behaviors such as hyperelasticity if you have a rubber material for example.

To evaluate if the stress has exceeded the linear elastic range of the material, you will need to know at least the Tensile Yield Strength. Strength values do not have to be put into the material definition since the calculation of stress and deformation is not affected by them being listed in the material.  If you do add the Tensile Yield Strength value to the material, it is used by the Stress Tool, a result that can include a Safety Factor (SF) plot, which just divides strength by stress so SF > 1 is good (stress below yield), SF < 1 is bad (stress above yield).

rrdbes posted this 29 April 2018

Thanks Peter! I also notice that during simulation at different design loads. And thank you for confirming, i'm havinf hard time because there;s so many variables needed to create a new engineering material. But i guess my simple 2D analysis of roof trusses and my input ultimate strength is enough.

Last question. can i use the total deformation result to calculte the flexural stress on roof element? Thanks!

peteroznewman posted this 30 April 2018

When you assign a linear elastic material to a solid body, that defines the stiffness of the structure. An applied force F will create a deformation x according to F = [K]x where the shape of the geometry and the material's Young's Modulus E define the stiffness matrix [K].

ANSYS solves this equation for the unknown values of x.  Once deformations are known, strains can be calculated. Once strains are calculated, stress is calculated using stress = E * strain. So solving the Static Structural model makes available deformation, strain and stress all at once.

rrdbes posted this 30 April 2018

So, can i use the value of the deformation as the value for deflection?

peteroznewman posted this 30 April 2018

 Deformation and deflection mean the same in ANSYS, which is the difference between a node's location before and after loading.

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