Topology Optimization of Flaring Tool Using OptiStruct

Transcription

1 Topology Optimization of Flaring Tool Using OptiStruct Rahul Nanche Engineer CAE Emerson Innovation Center Hinjewadi,Pune Sachin Magdum Lead Engineer Emerson Innovation Center Hinjewadi,Pune Abbreviations : FBD-Free Body Diagram, FEA-Finite Elemental Analysis, Keywords : Flaring, Static structural, Experimental testing, Prototype Abstract Flaring Tool plays an important role in Refrigeration and Automobile applications for making pipe fittings. In automotive uses, flaring tools help mechanics fit brake, fuel lines, cooling lines and transmission lines. Number of flaring tool manufacturers is available in market today. RIDGID is one of the prestigious brand in U.S.who has expertise in making professional tools since Flare fittings are a type of compression fitting used with metal tubing, usually soft steel and ductile (soft) copper, though other materials are also used. RIDGID make Model 345 which is a precision designed tool for producing 45 flares in soft copper, brass, aluminum and mild steel (JIC and Bundy) tubing. Scope of this paper is to optimize the Yoke of the Flaring tool in such a way that the performance of the tool and quality of flair obtained should not deteriorate. OptiStruct module of Altair is used as tool for optimization. The results are compared with FEM software ANSYS as well as in Radioss and prototype generation is in progress as per the optimized model. Introduction The product is designed a years ago, so there is scope for improvement, Aim is to achieve the balance between weight, cost & performance of tool (i.e. Quality of Flare). Flaring tool used to make flares of different angles like 37 or 45 on copper, aluminum and steel tub es of various sizes. The figure 1 shows an assembled view of flaring tool. To flare the pipe following steps needs to be carried out. 1. Insert tubing into proper size opening and close flaring bars. Push tube up from bottom of tool until it is even with top of flaring bars. 2. Slide Yoke until centered over top of tubing. Tighten Clamp Screw firmly. 3. Turn Feed Screw Handle to flare tube end. A flare is complete when handle cannot be turned any more. 4. Back Feed Screw out as far as it will go and release Clamp Screw to slide yoke back, remove tube. Figure 1: 345 Flaring Tool Assembly Weight of existing Yoke is lbf. Experimental testing was carried out to determine forces to yield the yoke and flaring bar assembly. Static analysis is carried out to simulate the behavior of the yoke under load. Deflection and stress constraints are imposed on yoke and topology optimization is carried out. Simulation Driven Innovation 1

2 Topology Optimization Procedure The goal of topology optimization is to find the best use of material for a body such that the objective criteria (volume, stiffness, natural frequency) take out a maximum or minimum value subject to given constraints (deflection, volume or mass reduction). Generally, topology optimization is carried out before shape or size optimizations. Preliminary stage of any static analysis is to decide the loading and boundary conditions, the experimental testing was carried out to determine the forces acting on yoke due to feed screw and clamp screw. The figure 2 shows FBD of the yoke. Figure 2: Loading and Constraints The base model static analysis results plays vital role in optimizing the part because it will give general idea about behavior of part under applied loading. Identified Design and Non Design areas so that material within the vicinity of threads should not affect (see figure 3). Simulation Driven Innovation 2

3 Optimization Type : Topology Constraints : Deflection, Stress Objective : Minimize Volume Figure 3: Design and Non Design Areas Allowable deflection and stress constraints were applied in OptiStruct. Minimum thickness as per the casting process was also one of the criterion. The results of structural analysis are as follows. Figure 4: Deflection & Von-Mises Stresses For Base Model After solving using OptiStruct module after 59 equilibrium iterations all constraints were fulfilled and results for optimized model were contoured. Got a general idea for reduction of material from non stressed regions, accordingly new optimized model was constructed and analyzed. Element density contour for last iteration is shown in figure 5. Simulation Driven Innovation 3

4 Figure 5: Element Density Plot As per the constraints applied on the base model deflection has not crossed experimentally tested value and stresses observed are close to the base model stresses. Figure 6: Deflection & Von-Mises Stresses from OptiStruct With Optimized Shape Accordingly new optimized model was created and carried out structural analysis in ANSYS. The results for deflection and stresses were compared with OptiStruct results. Simulation Driven Innovation 4

5 Figure 7: Optimized Yoke Model Considering product family we were not allowed to create through pockets, so made " I section" with possible reduction of material from base model of Yoke. Results & Discussions From the figure 5 (Element density plot) got an idea about amount of material to be reduced. By keeping the shape of the geometry same as that of Base model new optimized model was created (Figure 7).The deflection and stresses observed were reduced compared to base model. Figure 8: Deflection & Von-Mises Stresses For Optimized Model Simulation Driven Innovation 5

6 Benefits Summary Traditional method for optimization was to look for analytical calculations, but it's possible only for simple geometries. Second option was to carry out static structural analysis and by observation of stresses identifying the scope for shape and size optimization. With the help of "OptiStruct" total cycle time is reduced due to elimination of iterative process of refining model for structural strength as per base model and again analyzing it with FEA tool. Flexibility to apply constraints like deflection, symmetry, allowable stress etc, which will help to tackle the behavior of the part under various combinations of circumstances. It is a one shot tool for optimization. Weight of the base model was reduced to 11.13% with the help of topology optimization. In the family of flaring tools there are almost 10 various models available for optimization which will have huge impact on savings. Challenges Validation was the main challenge for this analysis, so experimental test is carried out and result were compared. Identification and application of constraints was also a difficult task so as to obtain feasible model. Capturing the shape from OptiStruct and converting it to a 3D model without disturbing it's product family look was an important aspect. Also from manufacturing point of view part should the easily casted and should have symmetric shape..future Plans Prototyping the optimized model is the preliminary task which is in process. Experimental test will need to carry out so as to compare the results with static results from FEA tool. To carry out above process for family of similar products so as to obtain considerable amount of material saving. Conclusions Radioss OptiStruct solver plays a role of key player in optimization projects. It's an one shot optimization tool which will provide idea for effective optimization with fulfillment of all the applied constraints. Total cycle time for production can be reduced and can turn business towards profitability through savings. Flexibility to play with applied constraints (Draw direction, Symmetry, Min thickness, Allowable Stresses etc) is an important feature which will help to design product from manufacturability point of view. ACKNOWLEDGEMENTS Sachin Dakare, Ridge Tool Company, Team Leader, Emerson Innovation Center Ghanshyam Rathod, Analysis Center Of Excellence, Sr.Tech Lead, Emerson Innovation Center REFERENCES [1] Altair OptiStruct Users Manual, Version 11, Altair Engineering Inc, [2] Mingzhou1, Raphael Fleury, Sam Patten, Topology Optimization - Practical Aspects for Industrial Applications [3] Simulation Driven Innovation 6