Joint creation and Demonstration in LS-DYNA

Objective: To perform side pole crash analysis on the scaled-down model of neon dodge under FMVSS conditions. Procedure: Import the given 0000.rad file into hypercrash. Fig 1: Neon dodge scaled-down BIW model. The units are checked in the rad file, and it is Kg mm ms. Fig 2: Units in the starter file. The penetrations…

Objective: To perform and simulate the non-linear case of Birdstrike in Aero-engine using explicit analysis in LS-Dyna. Procedure: The given keyword file BIRD_STRIKE consists of nodes and elements for all the four parts collectively, i.e., Engine casing, Blade, Hub, and Blade. Fig 1: Model and mesh information…

Objective: To demonstrate spherical, revolute, cylindrical, and translational joints between two rigid and deformable bodies. Theory: A distinguishing feature of multibody systems is the presence of joints that impose constraints on the relative motion of the various bodies of the system. Most joints used in…

Objective: To perform the Head Impact Simulation and calculate the Head Impact Criterion (HIC) value for the following cases: Simple head model impacting against a rigid wall. Child headform dummy model impacting against a rigid wall. Child headform dummy model impacting against the hood. Procedure: Case (1):…

Objective: To calculate the Mooney Rivlin and Ogden material constants and compare them using stress-strain data from a Dogbone specimen tensile test with 100 percent strain. Procedure: The stress-strain points are written in Excel and saved in .csv format to load into the LS-Dyna. Fig 1: Provided engineering stress and…

Objective: To model material data in LS-Dyna. Procedure: The provided stress-strain curve image is imported into the data digitizer. Fig 1: Stress-strain curve image is opened in the data digitizer to extract the curve points. From the data digitizer, the points from the 1st curve are exported into excel. Fig 2: The…

Objective: Calculate the Stretch Ratio by comparing the ELFORM (-2,-1,1,2) with Ogden_Material Model. Procedure: Open the provided file in the LS-Prepost. It contains the material card data.  Navigate to the Shape Mesher option in the Mesh menu in the right ribbon. Fig 1: Options for creating a box solid. Enter…

Objective: To simulate a crash test for a crash box with 1.2 and 1.5mm thickness using LS-Dyna. Procedure: Open the supplied .k file, which contains the mesh information of the crash box. Fig 1: Mesh information of the crash box. The initial keyword file contains only the element, node, and parts information…

Objective: To model spotweld using beam and solid elements and perform a crash simulation in LS-Dyna.  Procedure:  Open the provided keyword file in the LS-PrePost, which contains the mesh information of two rail components.   Fig 1: Meshed model. The initial keyword file contains only the element, node,…

Objective: To perform the simulation by reducing and stabilizing the runtime with the help of a mass-scale factor. Mass scaling: In an explicit method, the time step usually is tiny to maintain numerical stability. However, small step size prevents this method from being useful for routine analysis work. Mass scaling…

Objective: Creation of input deck for simulating cellphone drop test. Procedure:  Open the supplied .k file, which contains the mesh information of the mobile and the ground. Fig 1: Mesh information of the cellphone and the ground. The gound mesh contains both shell and solid elements. Red color elements are the shell…

Objective: To perform explicit and implicit method calculations on a given equation with a tolerance value of 0.001. Implicit method VS Explicit method Explicit: As opposed to Implicit methods, the explicit method is a function of time. This scheme needs to consider as a function of time, velocity, acceleration,…

Objective: Unit conversion for LS-DYNA. Conversion of SI units to gm/mm/ms unit system.  SI units (Kg, m, s) Converted units to gm, mm, ms Mass 1 Kg 1000 gm Length 1m 1000 mm Time 1 s 1000 ms Force 1N Force =mass * acceleration `1N=(kg*m)/s^2` =`(1000gm*1000mm)/(1000^2 ms^2)` =`1(gm*mm)/(ms^2)` Conversion factor=1…

Objective: To perform frontal crash analysis on the scaled-down model of neon dodge under FVMSS conditions. Procedure: Import the given 0000.rad file into hypercrash. Fig 1: Neon dodge scaled-down BIW model. The units are checked in the rad file, and it is Kg mm ms. Fig 2: Units in the starter file. The penetrations…

Objective: 1. Meshing of bumper assembly with six mm element size.                    2. Radioss interfaces (type 7 and type 11) and study the effect of notches with a crash tube example. Procedure: Meshing of bumper assembly: 1. Import the bumper assembly into hypermesh.…

Objective: To study material laws 1 (M1_ELAST), 2 (M2_PLAS_JOHNS_ZERIL), 27 (M27_PLAS_BRIT), and 36 (M36_PLAS_TAB) with a rupture plate example. Procedure:  1. Import the given 0000.rad file into hypermesh. Fig 1: Geometry of plate and a rigid ball. Case 1: LAW 2. The material card values and the failure card…

Objective: Comparision of 2D shell element formulations with beam crash example. Procedure: Import the 0000.rad file (started file) into hypermesh. Fig 1: Geometry information contained within the starter file. Case 1: Default settings. Change the simulation time from 60ms to 55 ms in the "ENG_RUN" card. Fig 2: Simulation…

Objective: To perform 2D meshing on the given models. Procedure: Model 1: 1. Import the given model into hypermesh. Fig 1: Given Geometry. 2. By setting the component by topo in the visualization setting, the free edges are visible in red color. Fig 2: Free edges in red color. 3. The free edge along the…

Objective: 1. To find out the time taken by the shock wave to pass through the rail.                    2. To create a 1D element and perform 3D tetra and hex mesh on the given components. Procedure: Calculation of the time taken by the shock wave to travel through the…

Objective: To generate 2D mesh on the rear wheel holder geometry. Procedure: 1. Import the given geometry file into hypermesh. Fig 1: Imported geometry file. 2. The button surfaces are deleted from the geometry, and a new plain surface is created in their place because elements will be failed to satisfy…

Objective: To generate 2D mesh on the side door of a car. Procedure: 1. Import the given geometry file into hypermesh. Fig 1: side door body geometry. 2. The geometry consists of so many ribs and supports with fillets less than our required element size, so defeaturing the fillets must be done to eliminate the…

Objective: To create 1D connectors on the frame assembly. Procedure: 1. Import the assembly into hypermesh. Fig 1: Imported assembly. 2. The frame assembly consists of the front truss, rear truss, right rails, left rails, and reinforcement plate. Fig 2: Components of the assembly. 3. Generate 2D mesh on the components…

Objective: To perform 3D tetra mesh on three models. Procedure: Model 1: 1. Importing the component into hypermesh. Fig 1: Imported housing model into hypermesh. 2. Performing the geometry clean-up on the model with the target element size, minimum (2 units), and maximum element size (7units) would save us some time in…

Objective: To generate 2D mesh on the hood geometry. Procedure: 1. Import the given geometry file into hypermesh. Fig 1: Imported geometry file. 2. The hood consists of four different components: outer extract, inner extract, latch reinforcement, and hinge reinforcement. Fig 2: Different components of the hood. 3. Autocleanup…

Objective: To Create 1D elements on a given component. Procedure: 1. Import the given bracket component. Fig 1: Imported geometry file. 2. Extract the mid surface from the solids using the skin offset method in the auto-extract option from the mid surfaces command.  Fig 2: Extracted mid-surface from the solids. 3.…