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Using FE to simulate the effect of tolerance on part deformation. By I A Manarvi & N P Juster University of Strathclyde Department of Design Manufacture and Engineering Management. Outline. Introduction Methodology Experimental phase Procedure
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Using FE to simulate the effect of tolerance on part deformation By I A Manarvi & N P Juster University of Strathclyde Department of Design Manufacture and Engineering Management
Outline • Introduction • Methodology • Experimental phase • Procedure • Tolerance Vs. deformation experimental results • FE simulations • Tolerance Vs. deformation FE results • FE deformation pattern at tolerance values • Comparison of Experimental and FE results • Conclusions
Introduction Tolerance Allocation in Product Design: • Vital activity for mass production and interchange-ability of parts • Required during design, Manufacturing, Assembly, Quality and performance evaluation phases. • Major influences on function, cost, customer requirements and aesthetics. Scope : Investigating use of FE simulations as a tool to verify influence of tolerance on part deformation at initial design stages
Methodology Experimental phase: • Selection of specific type of tolerance , a simplified geometry and commonly used material • Design and manufacturing of a test rig for experiments simulating tolerance conditions. • Execution of experiments and collection of data FE simulation phase: • FE modelling and simulation with ABAQUS softwarewith similar boundary conditions as experiments. • Collection of FE results at same Axis location as of experimental data
Experimental Phase Known Parameters: Selection of tolerance: Location of two hole centres Simplified geometry: Rectangular strip 200 x 40 x 1 mm Material : ABS plastics (Astyrn BR 712 A) Test rig designed and manufactured: Dial Indicator 1 Sliding platform Dial Indicator 3 Dial Indicator 2 Base Platform Rotary Knob Side supports Parallel Precision slides
Procedure Dial Indicator 1 for tolerance measurement Dial Indicator 2,3 for side deflection measurement Pin B (0.2, 0.4, 0.6, 0.8, 1.0, 1.2mm) Z Z X Y Y Pin A (Fixed) Rotary knob Out of plane deformation Z axis Specimen
180 1 40 200 FE simulations Model creation: Rectangular strip 200 x 40 x 1 mm • Material properties: ABS plastics ( Astyrn BR 712 A) • Material type = Elastic • Young’s Modulus = 106 e 3 MPa • Poison’s ratio = 0.39 Analysis steps : Initial & Step 1 with assumptions as: • Non linear geometries ON • Buckling criteria = Static Riks
Pin A Z Pin B Ux = 0.0 Uy = 0.0 Uz = 0.0 Rx = 0.0 Ry = 0.0 Rz = 0.0 Ux =Free Uy =Free Uz =Free Rx =Free Ry =Free Rz =Free Y X FE Simulations Boundary conditions: Pin B would move in steps to 0.2, 0.4, 0.6, 0.8, 1.0, 1.2 mm in X-axis Meshing conditions: Mesh seeds = 2mm Elements = Hexagon
FE Deformation Pattern of Model at Different Tolerance values 0.2 mm 0.4 mm 0.6 mm 0.8 mm 1.0 mm
Comparison of Experimental and FE Deformation at 0.2, 0.4 & 0.6mm
Comparison of Experimental and FE Deformation at 0.8, 1.0 & 1.2mm
IDEAS VISUALISER FEM 1 B.C. 1, DISPLACEMENT_1, RESTRAINT SET 1 DISPLACEMENT Magnitude Un averaged Top Shell Min: 0.00 mm Max: 2.07 mm Y X Z 2.07 All DOF free Y= 1.0mm Rest all DOF set free 1.97 1.87 1.76 1.66 1.56 1.35 1.04 0.93 0.83 All DOF constrained 0.73 All DOF free 0.62 0.42 0.00 FE Analysis of complex geometry
IDEAS FEM 1 B.C. 1, DISPLACEMENT_1 RESTRAINT SET 1 ELEMENT SIZE = 0.2mm Type: Thin shell 2.5mm thickness No. of Elements = Over 400,000 X Z Y Hole C Y= 1.0mm Rest all DOF set free Hole D No constrain applied All DOF constrained in Hole B All DOF constrained in Hole A FE Analysis of complex geometry
Maximum deformation Zone due to 1.0mm tolerance Deformed model Un deformed model mm 2.72 2.58 2.44 2.31 2.17 2.04 Un deformed model 1.90 Deformed model 1.77 1.63 1.49 1.36 1.22 1.09 0.95 0.82 0.68 No deformation Zone 0.54 0.41 0.27 0.14 0.00 FE Analysis of complex geometry
IDEAS FEM 1 B.C. 1, DISPLACEMENT_1 RESTRAINT SET 1 ELEMENT SIZE = 2.5mm Type: Thin shell 2.5mm thickness No. of Elements = Over 400,000 Y No constrain applied Y= 1.0mm Rest all DOF setfree SIDE VIEW Z FRONT VIEW Y All DOF constrained All DOF constrained FE Analysis of complex geometry X
IDEAS VISUALISER FEM 1 FRONT VIEW B.C. 1, DISPLACEMENT_1, RESTRAINT SET 1 DISPLACEMENT Magnitude un averaged Top Shell Min: 0.00 mm Max: 3.86 mm mm 3.86 No deformation 3.67 3.48 3.28 2.90 2.70 2.51 2.32 2.12 Max. deformation 1.93 1.74 1.55 1.35 1.16 0.97 0.77 0.58 0.39 0.19 0.14 0.00 FE of Automotive Glove box
Peak deformation at center of specimen reducing towards edges. FE and experimental results showed tolerance leading to deformation subsequently influencing part assembly Existence of a linear relationship between tolerance and deformation of parts confirmed by FE and experiments Similarity of experimental and FE results signified the possibility of using FE as a tool for tolerance allocation. Conclusions
Thank You for attention Questions ?