10_Impact analysis

Impact analysis or crash analysis is the process of studying the response of an object or structure to a collision or impact.

Understand and predict the forces, deformations, and extent of damage that occur during a collision with impact analysis.

Evaluate the accuracy of the results by comparing the Impact analysis with the actual crash experiment.

 

Why do we need conflict resolution?

1.Ensure safety

Impact analysis is used to establish and validate safety standards for vehicles, aircraft, buildings, and more. This ensures safety and reduces potential risks.

2.Improve product design

Impact analysis can help you identify and improve structural flaws in your product, resulting in a more complete product.

3.Save money and time

Real-world impact testing is very expensive and time-consuming. Impact analysis using computer simulations, on the other hand, can save you a lot of money and time.

 

Impact analysis can play an important role in identifying potential accident scenarios in advance so that you can prepare for them and determine their causes.

In this post, I will use HyperMesh, HyperCrash, and RADIOSS to analyze the following models for Impact analysis.

 

Create components and meshes in HyperMesh, save them as fem files, and import them in HyperCrash.

HyperCrash version is 2019.1.

 

Model - Material

Create New - Elasto plactic - Johnson Cook

In Johnson-cook, the material behaves as linear elastic when the equivalent stress is lower than the yield stress.

 

RHO_I : 7.85e-6

E : 210

Nu : 0.3

a : 0.206

Support : Select in graphics - include picked parts -> select all components

Save and Close

 

Model - Property

Create New - Surface - Shell

Thick : 0.914

Support : Select in graphics - include picked parts -> select all components

Save and Close

 

Create a rigid element.

Mesh Editing - Rigid Body

Gnod_id : Select in graphics - add nodes by box selection -> select a node in the back

Save and Close

 

 

Create boundary condition

LoadCase - Boundary Condition

Check all except TZ

Gnod_id : Select a rigid node

Save

 

Create new boundary condition

Check all dof

Gnod_id : Select a wall

Save and Close

 

Speed settings

LoadCase - Imposed - Imposed Velocity

Create New - Imposed velocities

Dir : Z

funct_IDT : Define Function

grnod_ID : Select a rigid node

Save and Close

 

Set contact conditions

LoadCase - Contact interface

Create New - Multi usage

multi usage can effectively and efficiently handle different types of contact situations simultaneously. It can also properly model multiple contact conditions in complex simulations, improve simulation accuracy, and reduce setup time.

Self Impact : check

Stfac : 1

It is used to control the strength of the reaction at the contact interface. A higher Stfac value means a stronger contact reaction.

Gapmin : 0.9

Sets the minimum distance for contact to be activated. This value defines the minimum allowable distance between two surfaces, within which contact is detected and the contact response is activated.

Fric : 0.2

Represents the coefficient of friction based on the Coulomb friction model. This coefficient determines the magnitude of the frictional force between two contacting surfaces.

Mast_id : select all components

Save and Close

 

 

Model - Control Card

RUN_NAME_NUMBER_LETTER

Run Number : 1

DT_STOP : 10.01

save

ANIM_DT

TFREQ : 1

save

PRINT

Print : -100

save

ANIM_ELTYPE_RESTYLE

Type of element : ELEM

Name of the variable to be saved : VONM: von Mises stress

save

ANIM_VECT

create VEL and CONT

Save and Close

 

File - Export - RADIOSS - save model

Run Radioss

Import ###_0000.rad file

##_0000 : analysis model

##_0001 : analysis conditions and parameters

 

 

 

Through the analysis, we were able to see various numbers such as displacement and stress, and we can adjust the size of the element and the PRINT value to get smoother and more accurate results.