Side Car Crash test

AIM:

To perform the crash analysis for the given model and notify the energy difference.

METHODOLOGY:

• Importing the model.
• Checking the units and changes made if any.
• Create the required parameters and cross sections.
• Plot the graphs with different energies.

INTRODUCTION:

PROCEDURE:

• Import the .hm file.

• Check the units in BEGIN _CARD.
• Units to be followed as “Mass(kg), Length (mm), Time (ms)”.

INTERFACE:

• New Interface is created and name it type 7.
• Change the card type to TYPE 7 and modify the necessary parameters.
• Select the Slave entities and Master Elements.
• Give the values of Istf (stiffness definition) as 4, Igap (gap/element option) as 2, Idel (Nodes and segment deletion) as 2, Irem_gap () as 2, Irem_i2 () as 0, stfac () as 2, Fric () as 0.2, Gapmin () as 0.5, Inacti () as 6, Iform () as 2.

RIGID WALL:

• Create a rigid wall by right click on tab area and RWALL and select ‘Cylinder’.

• Select the geometry type as ‘Infinite plane’.
• Set the coordinates with selected base node for creating rigid wall.
• Select the Normal around the axis as per requirement.
• Give the Slide value as 2, Dsearch value as 1000, Fric Value as 0.1.

COG point:

• Check the COG point and modifies accordingly by adding node mass.
• Go to Tools menu, click on Mass Details and select the Mass,inertia and COG.
• A dialogue box pop up and check for the COG coordinates.

• Copy those coordinates and create a new node with those coordinates.

• If COG is not in required position the node mass is to be added.
• Right click on tab area and select ADMAS, a new card is created.

• Right click on gmd_ID and select create.
• Select the nodes for adding the mass with approx mass value.

INITIAL VELOCITY:

• Right click on tab area, select the BOUNDARY CONDITIONS.
• Select INIVEL, a new card is created.
• Right click on gmd_ID and select create.
• Select the displayed nodes and click proceed.
• Set the velocity value as 15.64 mm/ms (35mph as per question).
• Select the nodes for direction of velocity.

CROSS-SECTIONS:

• Right click on tab area, select SECT in create menu.
• New card is created, select three nodes for N1, N2, N3.

• Right click on gmd_ID and select create.

• Click on Entity ID’s, select the nodes for cross sections.
• Give the deltaT value as 0.1 and alpha value as 1.67.
• Create a new Frame card in Solver Browser by right click in tab area.
• Select the three nodes for creating axis.

• Right click on grshel_ID and select elements for cross sections.

• Give Iframe values as 12.
• Follow the same procedure for cross sections at different locations.
• To call out the cross sections created, click on Output blocks in Model browser.
• Create a new output block and rename it as cross sections.
• Click on Entity_ID and select all cross sections created.

PEAK VELOCITY:

• Right click on tab area in model browser.
• Create a “Moving Skew”, a new card is created.
• Select the nodes for the axis.
• In Model browser, create a new Output block and rename it.
• Select the node on the inner door and also skew system.
• A new Output block card is created.

INTRUSIONS:

• Go to the Tools panel , click on numbers ,Select the nodes ,click on ID, give the node id as specified (given 66695, 66244) ,Click on display.

• Right click on tab area, click SKEW option, select MOV option , give a name to it ,select the nodes ( origin, axis, Plane nodes)
• Create a new Output block and rename it.
• Select the displayed node and skew system.

PENETRATION CHECK:

• Go to Tools, select penetration check.
• Select groups and proceed.

ERRORS:

• Go to Tools, select the model checker.
• Go to Solver Browser, right click on Error and select RUN.
• Clear errors if any.

RUNTIME & TIME STEP:

• Click on ENG_RUN in cards in model browser.
• Change the Tstop value as 80.

• Click on ENG_ANIM_DT and set Tfreq as 0.1.

OBSERVATIONS:

• Hourglass energy is constant as Ishell parameter is set to 24.
• Contact Energy is increasing slowly as the time goes.
• Internal Energy is gradually increasing and kinetic energy decreases gradually.

• The Intrutions of hinge pillar, B pillar and fuel tank are increasing gradually.

DEFINITIONS:

Centre of Gravity:

The center of gravity (CG) of an object is the point at which weight is evenly dispersed and all sides are in balance. A human's center of gravity can change as he takes on different positions, but in many other objects, it's a fixed location.

Accelerometer:

An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system.

Peak Velocity:

The peak velocity is the highest velocity attained during the impact of an object at a particular time.

LEARNING OUTCOME:

Learned how to create

• Intrusions
• Interface
• Accelerometer
• Initial Velovity
• Rigid wall
• Cross sections.
• CoG

Learnt how to check errors and rectify it.

RESULTS:

The Simulation is completed successfully.

The Plotting of graphs is achieved successfully.

Energy Plots:

The energy plots are created between hourglass energy, Total Energy, Kinetic Energy, Internal Energy, and Contact energy versus Time.

Section Plots:

The plots for the cross-sections have different displacement values as the different components have different stresses acting upon it while performing a crash analysis.