Example33 Analysis of an Fallen Object

General

  • An object consisting of a substrate and a frame falls onto the floor and bounces off.
     

  • The deformation, the displacement and the mechanical stress are solved.
     

  • Unless specified in the list below, the default conditions will be applied.
     

  •  

 

Analysis Space

Item

Settings

Analysis Space

3D

Model unit

mm

 

Analysis Conditions

Item

Settings

Solvers

Mechanical Stress Analysis [Galileo]

Analysis Type

Transient analysis

Large deformation

Large displacement

Options

Select “Acceleration”.

The acceleration, the transient analysis, and the high-level setting tabs are set up as follows .

Tab

Setting Item

Settings

Acceleration

Acceleration

(X,Y,Z) = (0, 0, -9.8)[m/s2]

Transient analysis

Time step

0.0005[sec]

Calculation steps

20

Output steps

1

Model

The object falls from the height of 1.5[m].

The calculation starts when the object is 0.001[m] off the floor, at which time the object has the initial velocity of -5.420369[m/s].

The frame and the substrate are solid bodies. The floor is a rigid body.

 

 

Body Attributes and Materials

Body Number/Type

Body Attribute Name

Mesh Size

Material Name

9/Solid

FRAME

10

001_Al *

10/Solid

SUB

5

008_Cu *

11/Solid

RIGID

 

Rigid

* Available from the Material DB

 

Material property of the rigid body is set up as follows.

Material Name

Tab

Settings

Rigid

Elasticity

Young’s modulus: 1.0e20[Pa]

Poisson’s ratio: 0.0

Density

1000[kg/m3]

 

Initial velocities are set in the body attributes.

Body Attribute Name

Tab

Settings

FRAME

Initial Velocity

(X,Y,Z) = (0, 0, -5.420369)[m/s]

SUB

Initial Velocity

(X,Y,Z) = (0, 0, -5.420369)[m/s]

Boundary Conditions

The bottom face of the frame makes a contact with the top face of the rigid floor.

The displacement of the rigid floor is set to zero, because it is fully fixed.

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Settings

Contactor/Face

Mechanical

Contact surface

Contact Surface Classification: Contactor surface

Target/Face

Mechanical

Contact surface

Contact Surface Classification: Contactee surface

Fix/Face

Mechanical

Displacement

Select UX, UY, and UZ all.

Set all components to zero.

 

* After setting the contact surface, go to the [Model] tab,


 

and click [Boundary Pair] . Pair “Contactor” and “Target” in the Boundary Pair dialog box.

Results

The general mesh size is set to 14.

The contour diagrams below show von Mises equivalent stress. Note that “Specify ratio” is set to 10 on the Displacement Diagram tab of [Graphics Setup].

The rigid body is hidden.

 

The moment of the collision (t = 0.0002[sec])

 

0.0001 seconds after the collision (t = 0.0003[sec])

 

0.0003 seconds after the collision (t = 0.0005[sec])

 

These diagrams show that the substrate deforms as time passes since the collision.