# Finite Element Analysis of Collision Impact in MD Patran/Nastran

• abkdt41
In summary, the conversation discusses the use of MD Patran/Nastran for running a finite element analysis of a collision impact. The speaker has created the mesh and applied appropriate material and boundary conditions, but the solver does not show the results. They have also done static analysis, but are now trying to calculate the total impact force and use static analysis on the object being hit. The topic of contact conditions in the simulation is also brought up, and the conversation concludes with the suggestion that dynamic analyses are complex and the speaker may not have the necessary expertise to successfully conduct one.

#### abkdt41

I am trying to run a finite element analysis for a collision impact. The program I am using is MD Patran/Nastran. My model consists of moving object colliding with a stationary object. I have created the mesh, applied the appropriate material, applied the boundary conditions (fixed for the stationary object, and velocity for the moving object) Is there anything that I am missing, since the solver does not show the results.

I have done some static analysis prior to this and have always gotten results.

You may be better off calculating what the total impact force of the object is, and then doing static analysis on what's being hit.

How do you define contact in the simulation?

abkdt41 said:
I am trying to run a finite element analysis for a collision impact. The program I am using is MD Patran/Nastran. My model consists of moving object colliding with a stationary object. I have created the mesh, applied the appropriate material, applied the boundary conditions (fixed for the stationary object, and velocity for the moving object) Is there anything that I am missing, since the solver does not show the results.

I have done some static analysis prior to this and have always gotten results.

abkdt41 said:
I am trying to run a finite element analysis for a collision impact. The program I am using is MD Patran/Nastran. My model consists of moving object colliding with a stationary object. I have created the mesh, applied the appropriate material, applied the boundary conditions (fixed for the stationary object, and velocity for the moving object) Is there anything that I am missing, since the solver does not show the results.

I have done some static analysis prior to this and have always gotten results.

A dynamic collision model is a LOT more complicated than a steady-state linear analysis. You didn't mention anything about contact conditions or how you're detecting contact, so I'm going to guess that in the model the components fly right through each other and don't collide.

Even if you were able to add proper contact conditions, I think it's pretty unlikely you'll be able to get useful results out of the model. Dynamic analyses are a fine art, and I think you're probably in over your head.

## 1. What is Finite Element Analysis (FEA)?

Finite Element Analysis (FEA) is a computer-based numerical method used to analyze the behavior of a physical system by dividing it into smaller, simpler elements. These elements are connected at common points called nodes, and the behavior of the entire system is determined by solving equations at each of these nodes.

## 2. What is the purpose of conducting FEA on collision impact in MD Patran/Nastran?

The purpose of conducting FEA on collision impact in MD Patran/Nastran is to simulate and predict the behavior of a structure when subjected to a collision impact. This can help engineers and designers understand the potential damage and deformation that may occur in a real-world collision, and make necessary adjustments to improve the structural design.

## 3. How does FEA in MD Patran/Nastran work?

FEA in MD Patran/Nastran works by first creating a finite element model of the structure to be analyzed. This involves dividing the structure into smaller elements and assigning material properties and boundary conditions. The software then uses mathematical equations and algorithms to solve for the displacement, stress, and strain at each node, resulting in a visual representation of the structure's behavior under the given impact.

## 4. What are the benefits of using FEA in MD Patran/Nastran for collision impact analysis?

There are several benefits to using FEA in MD Patran/Nastran for collision impact analysis, including its ability to accurately predict the structural response to impact, its cost-effectiveness compared to physical testing, and its flexibility to simulate various impact scenarios and make design changes accordingly. FEA also allows for a quicker and more efficient analysis process, which can save time and resources in the design and development of structures.

## 5. What are the limitations of FEA in MD Patran/Nastran for collision impact analysis?

While FEA in MD Patran/Nastran is a powerful tool for analyzing collision impact, it does have some limitations. These include the need for accurate input data and assumptions, as well as the potential for errors in the model and analysis setup. FEA also cannot account for all real-world factors, such as material imperfections and complex contact interactions, which may affect the accuracy of the results.