Week - 5 - Modelling Spotwelds

AIM: To perform crash analysis of crash box, in which spotwelds are used.

1^st case, by using beam as spotweld and

2^nd case, by using hexa element as spotweld.

Then comparing their both cases results.

Procedure: Load the given model to LSPREPOST GUI

1^st case, by using beam as spotweld

File > open > lsdyna keyword file

Now create spotwelds between the plates by using beam element as shown below

ELEMENT TOOLS > ELEMENT EDITING > CREATE > BEAM > BY NODE OPTION

Assign sections for plates and spotwelds

KEYWORD MANAGER > SECTION> SHELL

KEYWORD MANAGER > SECTION> SHELL

KEYWORD MANAGER > SECTION> BEAM

Now we create material for plates and spotwelds

KEYWORD MANAGER > MAT > 024 PIECEWISE LINEAR PLASTICITY

KEYWORD > MAT > 100 SPOTWELD

TFAIL =5, here we want spotweld to fail at half of the termination time.

Assign mat and sec to parts

KEYWORD MANAGER > PARTS

Select the nodes of beam and make nodes set

Select the parts and make part set these set are used in creating contacts

KEYWORD MANAGER > CONTACT > AUTOMATIC SINGLE SURFACE

KEYWORD MANAGER > CONTACT > TIED SHELL EDGE TO SURFACE

Apply boundary condition, assign velocity of 13.89 mm/ms for crash box

Create rigidwall as shown below

CREATE ENTITY > RIGIDWALL > RIGIDWALL

Define control energy

Setup termination time = 10ms

Create two cross-sectional planes for crash box as shown below.

CREATE ENTITY > DATABASE > CROSS SECTION

Now request for outputs as shown below.

Save the model and run the model checker, if no error found (ignore warnings) then submit for run.

Check for normal termination

2^nd case by using hexa element as spotweld.

Now we replace beam elements by hexa elements. Update the model with section solid and contact.

Results

1^st case, by using beam as spotweld 2^nd case by using hexa element as spotweld

1^st case, by using beam as spotweld 2^nd case by using hexa element as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

1^st case, by using beam as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

2^nd case by using hexa element as spotweld

1^st case, by using beam as spotweld

2^nd case by using hexa element as spotweld

1^st case, by using beam as spotweld

2^nd case by using hexa element as spotweld