Superposition of loadcases in FEA software (with SPC+inrel)

In summary, finite element analysis software like Hypermesh uses superposition of loadcases applied on the same model by constraining different loadcases with standard SPCs and inertia relief constraints. The inertia relief method applies a fictitious force to each grid point associated with a mass to resist applied loadings. This is effective for modeling unconstrained structural systems such as aircraft in flight or cars on a test track. In the case of topology optimization, FEM software can superimpose different loadcases to arrive at a final result.
  • #1
marellasunny
255
3
I am curious as to how finite element analysis software(like Hypermesh) go about superposition of loadcases(applied on the same model). I constrain my vehicle body for 1.loadcase (say bending) with the standard SPC's and constrain my 2.loadcase(say torsion) with Inertia relief constraints. Given that inertia relief constraints require the FEA software to do a completely different set of calculations as compared to the standard SPCs, how is it possible to even superimpose the 2 loadcases?

FYI:
Inertia relief analysis is regarded as an effective technique for the modeling of unconstrained structural systems, for example- aircraft in flight, car on a test track etc. Inertia or mass of the structure is used in Hypermesh to resist the applied loadings. The ‘Inertia relief method’ applies an acceleration to the mass of the model in a way to balance the force applied. In essence, ‘inertia relief’ creates a fictitious force on each grid point associated with a mass.
 
  • #3
In case of a topology optimization (optimal material distribution), how do FEM software superposition different loadcases to arrive at one final result?
 

FAQ: Superposition of loadcases in FEA software (with SPC+inrel)

What is superposition of loadcases in FEA software?

Superposition of loadcases in FEA software is a method used to combine multiple loadcases in a finite element analysis (FEA) model. This allows for the analysis of the combined effects of different loads on a structure or system.

How does superposition of loadcases work in FEA software?

In FEA software, the superposition of loadcases is achieved by applying the loads and constraints from each individual loadcase separately, and then adding the results together to obtain the combined effect. This is based on the principle that the response of a structure to multiple loads can be determined by adding the responses to each individual load.

What is the purpose of using SPC+inrel in superposition of loadcases?

SPC+inrel is a method used in FEA software to define and maintain the compatibility of constraints between different loadcases. This ensures that the constraints applied in each loadcase do not interfere with each other, allowing for accurate superposition of loadcases.

What are the advantages of using superposition of loadcases in FEA software?

Superposition of loadcases allows for the analysis of the combined effects of different loads on a structure, providing a more realistic and accurate representation of the behavior of the structure. It also allows for the examination of the effects of individual loads separately, making it easier to identify the main contributing factors to the overall response.

Are there any limitations to using superposition of loadcases in FEA software?

While superposition of loadcases is a useful tool in FEA software, it does have some limitations. It assumes that the structure has a linear response to the loads, and may not accurately capture the effects of non-linear behavior. It also requires careful consideration and application of constraints and loads, as errors in defining these can affect the accuracy of the results.

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