Week - 3 Drop test Challenge

Aim: Perform drop test simulation using Ls Dyna

Objective:

• Assign material and section to the parts
• Create Boundary conditions
• Create contact between Plate and Mobile
• Assign Initial Velocity to Mobile
• Analyze forces, energy, and deformation

Procedure:

Import: Import the meshed keyword file in LS Dyna Prepost

Material:

• In this simulation, the kg-mm-s units system is used.
• For Plate Rigid (020_rigid) material is used while for mobile phone aluminum is considered(024_piecewise_linear_plasticity)

Section:

• Section keyword is used to define the type of element i.e. solid, shell, or beam
• The section is created using Model>section>Shell
• In the section tab, it is important to define element formulation and thickness of shell element, In this case, element formulation 2 is considered.
• For mobile, Model>Section>Rigid

Boundary Condition

• It is necessary to provide boundary conditions such as constraints, initial parameters like displacement, velocity, or forces acting on parts
• In this case, node-set IDs are created for Plate and Mobile. Node set ID of the plate is used as a single point constraint and Node set ID of Mobile is used to assign Initial Velocity.

Initial Velocity

• According to boundary condition, the initial velocity of 2000mm/s in the negative z-direction is given
• Node set data of mobile is selected

Contact:

• It is necessary to define contact between Plate and Mobile to analyze the impact and forces.
• Contact_Surface _to_Surface is considered in this case. All phone elements node are considered as slave and plate nodes as Master

Control

• Control_Termination Card is used to defining simulation time

Output

BINARY3DPLAT

ASCII

GLSTAT - To calculate energies like KE, PE and internal Energy

MATSUM- Material part energy calculation

RCFORCE- Contact Force

SPCFORCE- Single point contact force

Postprocessing:

• The saved keyword file is selected as input for LS Dyna Solver(LS RUN).
• In LS Prepost D3PLOT file was loaded and animation and plots can be seen
• ANimation can be seen in the link given below:https://drive.google.com/file/d/1OwaZD1_JmT3Kb-oQi2lYUunlfEbiCqJx/view?usp=sharing

In the below fig. Von misses stress developed at the mobile phone can be seen.

Initially, it can be seen that velocity is maximum therefore kinetic energy is also maximum. but during the impact, kinetic energy is get absorbed by the plate, and at the same time internal energy increases.

Conclusion:

Drop test simulation is successfully performed using LS Dyna. All the objectives are fulfilled and results are recorded.