Technical-Report-1

Technical Report Tutorial “Forming to Crash” using Hyperform-LS DYNA - - By: NIM: Le Hoai Tam 23615703 In this tutorial, we assume that you have already known how to use Ls Dyna for impact simulation Initial requirements There are two main methods in sheet metal forming: one step and incremental analysis Incremental analysis includes some different approaches such as: tube bending, hydroforming and deep drawing In this tutorial, deep drawing will be used Top hat profile is selected as a suitable component in this research To prepare for forming simulation with deep drawing method some requirements should be satisfied:  Forming tool: Die which is designed by CAE software ( Solidworks, Catia…) and saved IGS format  Calculate Blank (metal sheet) dimensions to obtain desired geometry Example: Dimension of desired geometry To get dimension of geometry as figure above, dimension of die should be calculated and presented as picture below Dimension of Die Forming Simulation Step 1: starting HyperForm The HyperForm user interface includes the following analysis configurations:  Radioss one step: setup, run and review of a one-step analysis  Incremental_radioss: setup and run an incremental analysis using Radioss solver  Die module: create and edit binders and addendums  Incremental_LS-DYNA: setup and run an incremental analysis using LS-DYNA solver After starting Hyperform, the following dialog appears In the Application: select, Manufacturing solutions, check option HyperForm, pick on narrow to roll list down and select Incremental_Ls-Dyna Click ok Step 2: import IGS file In the Toolbar click File=> import=> geometry Dialog appears Click on folder symbol to lead to IGS file, select IGS file and click Import, click close Die has been displayed as picture Step 3: geometry auto cleanup (to create good mesh quality) Step 4: Mesh for Die Enter number as picture below and click Mesh=> click Surface=>click Display=>click Proceed Step 5: reorient for Die to consistent with stamping direction (Z-axis) Initial position After reoriented To reorient component: Geometry => rotate=>component Click , click , click select axis and angle and click rotate until obtain desired positon as figure above Step 6: Create and rename "Blank" and "Die" Step 7: Create geometry & translate for Blank Geometry menu=>Create=>Surfaces=>Spline/Filler=>Type = nodes Select corner nodes to create Surface blank Geometry menu=>translate=>component=>Blank=>z axis=> enter 20mm in box magnitude, click translate + Create Mesh for blank geometry (Mesh=>B Mesh: Size = 5mm) Step 8: Create blank section & properties Click Setup=> section In the Section: field, type Blank_section In the thickness: type 2mm Click card image: select Sectshell Click Create Click return Step 9: Create blank material properties  Note: material used in this study is Steel ST37, E=115000MPa, Density: 7.96e-9ton/mm3, sigma yield: 215 MPa, n=0.12, k=398Mpa, R=1  Note: unit system Click Setup=> Material In the Material: field, type Steel ST37 Click card image: select TransAnsioEplasticPlastic Click import curve 5 In the curve: type Stress_strain curve In the Sigy: 215 MPa In the K: 398 MPa In the n: 0.12 Click create 10 Click back 11 Click create 12 Click return Step 10: assign section and material properties for the Blank component Click Setup=> components Double click component and select blank Click Setup=> Blank_section Click material: select Steel ST37 Select the adaptive checkbox Click update Click return Step 11: display only the Die component In the Model Browser, expand component folder Right click on the Component folder and select Hide Right click on the die component and select show Die component appears on the screen Step 12: build the Punch and Binder components (important!!!!) Click setup=>tool setup Select the Built and setup tool from die surface subpanel For Machine type, select Double acting, t= mm Click on yellow elements button in the binder source: field The element selector panel appears Click elems, select on plane If necessary, click the witch to the N1, N2, N3 and B option Pick four nodes on the binder for N1, N2, N3 and B as show below Click select entities, and then select proceed Click Build This will extract the punch and binder surface from the die cavity Click close Note: after execution, binder and punch components are generated The punch offset amount is set using the blank thickness value The punch offset is calculated to be thickness plus 10% (default value) In this case, it is 2+0.2=2.2mm This step is very important It will help you avoid clearance errors when running analysis!!!!!!! Tool=>tool offset, subpanel appears Click autoposition=>comps=> click punch, binder and die respectively and offset them along z axis with a distance is 2.2 for this case  This tool build macro creates blank and tool sections and tool materials In case these are already created, it will be updated  It also creates contact viz between blank-die, blank-punch and blank-binder Step 13: Define the tool motion Click setup=>tool motion Click moving tool and select the punch component Verify all options are set to: translation, velocity, linear, termination,load curve and loadcol are also checked Click maximum velocity: enter -5000 mm/s Click total travel and type 64.16 mm Note: the total travel is distance the punch and die- blank thickness and tolerance To calculate distance of punch_die, Pressing F4 a subpanel appears and try to select, identical nodes on the die and punch See picture below 6 Click setup Click history subpanel on the left      Click cycle/travel and type 500 ( cycles/mm of tool travel) Click update Notice time_step is change to 4e-7 Click motion Click update Click return Step 14: Define the binder load From the utility menu, under setup, click tool load Click tool and select binder Click tool force type -100000N Click max velocity and enter 500(mm/s) Set up Click return Step 15: save the analysis setup as Tam.hf From file menu, click save as Use the file browser to save the file as Tam.hf Click save Step 16: review the animation and run the analysis From the utility menu, under set up, click run Click create dynain (important!!!!!) Click applied comps:comps and select blank Click select Select the DYNA checkbox to enable DYNAIN output Click setup Note: at the end of the computation, dyna will write out a file called “dynain” This file contains all the thickness, stress and strain information necessary to perform subsequent operation Click return Click animation Note: this animation feature enables you to review and correct the tool motion Click dyna file and type Tam for the name 10 Click run Note: default solver in HyperForm is Radioss solver You cannot use this solver for this study Therefore you should change to LS DYNA solver To this, double click solver in the subpanel, a dialog appears you use browser to select LS DYNA solver We have another way easier After pressing run a Dyna input file named Tam.bdf is generated This file can be submitted directly to LS-DYNA as K file Step 16: analyze forming result We use Hyperview to see forming result Starting Hyperview Hyperview will read file d3plot similar to Ls prepost We use browser to select file d3plot as picture above and click apply.model will display on the screen as show below On the left hand side click folder component=>right click sheet and select isolate only to get final shape which we want to obtain as picture below To see Forming limit diagram: click Tool=>FLD, a dialod appears, click add=>click apply=>click FLD=>click apply To see residual stress, plastic strain, thickness distribution Click folder result on the left of the screen=>click scalar=>click % thichness reduction, stress, strain respectively to get result 3 Transferr forming result to crash analysis As already mentioned above In the end of the forming we will get a Dyna file output named “dynain” This file contains all the thickness, stress and strain information necessary to perform subsequent operation To conduct crash simulation combine with forming effect, keyword *INCLUDE is used Step Starting Ls prepost=>click keyword manager=>click Include, a dialod appears=>click Browse to select Dynain file=>click insert=>click accept=>click done Step 2: click file=> save as=> exit Note: save the same folder with Dynain file Step 3: starting Ls prepost again click file=>open file k which you just save before and we get result as figure below Finally, forming result has been transferred to Ls-dyna Now, you begin simulating crash analysis regularly Note: before starting to carry out crash simulation you have to reorient component to initial position To make sure forming result been transferred to Ls DYNA, click keyword manager.we will see result as picture below Finish