DESIGN AND OPTIMIZATION OF EXCAVATOR

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1 DESIGN AND OPTIMIZATION OF EXCAVATOR G.Ramesh 1, V.N.Krishnareddy 2, T. Ratnareddy 3 1,2 P.G. Student, Mechanical Engineering Dept., Chaitanya Bharathi Institute of Technology, Hyderabad- 75,AndraPradesh,India. 3 Prof Mechanical Engineering Dept., Chaitanya Bharathi Institute of Technology, Hyderabad-75, Andhra Pradesh, India. Abstract-The hydraulic excavators are one of the earth movers playing a major role in the development of the infrastructure like excavation, road construction, building construction, granite mining, ore mining, Coal mining etc. Excavators are generally equipped with a work implement or attachment for performing useful work. Such attachments include digging and material handling buckets, drills, and hydraulic hammers. To reduce number of iterations during the development process, the computational simulation method is used in Excavator for Multi Body Simulation analysis. An explicit finite element code like Altair Radioss is used for the simulation. Optimization is carried out to improve the Lower arm Excavator model to get less weight and stiffest component. This paper explains the FE analysis of Excavator of Lower Arm. All the results obtained from the CAE analysis are evaluated against the requirements which could reduce the process development time and cost. Aim of the Project is to Design and do Multi Body Simulation analysis for Excavator and Perform Topology Optimization to reduce the Weight of the Lower Arm Excavator. Catia V5 R19 for modeling Excavator and Preprocessing in Hyper mesh and Radioss for solving results are viewed in Hyper view. Altair Optistruct is used for weight reduction and change in design of Excavator of Lower Arm. Keywords Excavator, Radioss, CAE Analysis, Topology Optimization,Altair Hyper mesh. I. INTRODUCTION The development of new hydraulic excavators of the medium class that have embodied various design concepts like an IT technology, safety and global environment, basic performance, etc. Named hydraulic excavators in KOMATSU Series, the new machines have been introduced in the world markets with success. This paper takes up one of them, PC200-7, as a sample to explain the background of the development, the technology that sustains the design concepts and features of the product. (1) To provide our customers with solutions to their problems through making the most of available IT (Information Technology) (2) To help alleviate the environmental burden on the earth (3) To help establish safer working environment (4) To provide high basic performance and quality of machine that are tenable worldwide. Those concepts were further developed into the following seven items of concepts for new hydraulic excavators in KOMATSU Series. (1) Basic performance To establish compatibility a large production and low fuel Consumption (2) Comfort ability To assure a comfortable environment in the operator's cab with a low noise level and little vibration. (3) Global environment DOI: /IJRTER SIP3H 535

2 To mount an engine of clean gas emission and low noises (4) Safety To clear safety standard in each country International Journal of Recent Trends in Engineering & Research (IJRTER) Fig1: KOMATSU Excavator Motion As per the motion shown in the above figure excavator is carried out time related motion to the Boom, Boom Cylinder, Arm, Arm Cylinder and Bucket. These are the designs are generated a three dimensional model using CATIA V5R19 Software. Then imported in to Altair Hyper mesh for preprocessing, Radioss is to run the motion simulation for 1second time. Research objectives The main objectives of the proposed research work are as follows: Design of the backhoe excavator attachment for light duty construction work that has The higher kinematic working ranges with optimum dimensions and can be applicable for autonomous excavation task. to develop a mathematical kinematic model for four degrees of freedom backhoe mechanism to study the motion of backhoe attachment. to develop a mathematical dynamic model for digging mode having three degree of freedom (excluding the first degree of freedom that is swing motion). The proposed dynamic model used to predict dynamic forces developed during the digging task and also helpful to design controller to get controlled motion of backhoe attachment. It means it can be applicable for autonomous application for excavation task. To perform structural weight optimization of backhoe attachment using FEA approach without compromise in strength to reduce the weight to cost ratio. Project Objective The objective of the problem is to get the less weight design of Lower Arm using latest technology software s like Altair Hyper mesh, Radioss and Optistruct software. Modeling Using CATIA V5R19 This thesis ford car 3d model is designed using CATIA V5 R19 Software. This software used in automobile, aerospace, consumer goods, heavy engineering, etc... Catia V5 R19 is very powerful software for designing complicated 3d models. CATIA - Automotive Body-In-White Fastening 3 (ABF) is dedicated to the design of Automotive Body In White Fasteners. It supports Welding technologies and mechanical clinching along withadhesives,sealer,andmastics. The same CATIA V5 R19 3d model and 2d drawing model is shown below for reference. Dimensions are taken from KOMATSU OEM. The design of 3d model is done in Catia v5r19 software, and then to do test we are using below mentioned software s. Drawing Files are mentioned below based on original component, Using Catia V5 R19 Software All Rights Reserved 536

3 developed excavator Lower arm, Boom, Bucket and holders of lower and boom component. As per the dimensions the design of excavator is developed using CATIA V5R19 Software. Three dimensional models are shown below for reference. Fig2: 3D model after designed in Catia Fig 3: 3D model rear view in Catia Fig 4 : 3D model Side view in All Rights Reserved 537

4 Fig5 : 3D model Top view in Catia Three dimensional model is designed in Catia v5 r19 software and then generated 2 dimensions are generated the same is shown in above figures. Next after designing the model we need to do testing on the assembly components, for that we need to select the software for finite element analysis and then optimization is carried out for the lower arm of the excavator. Optimization removes the unwanted material in the component and then it is gives us innovative shape. After that we need to check the comparison of displacement and weight of the two lower arm components. II. PREPROCESSING OF EXCAVATOR CATIA 3D Model CATIA 3D model, we are importing in to Altair Hyper mesh for preprocessing, for solving we are using Altair Radioss software and for viewing the results Altair Hyper view. Due to huge weight of lower arm of excavator, we are taking complete lower arm for Optimization to achieve the less weight of the model and to get concept shape of lower arm. For above analysis methodology and to check strength of lower arm, we need to check stiffness of the frame using different approaches. As per Automobile OEM s (Original equipment manufacturer) to check strength of excavator motion, physically they will apply force like digging. The same physical problem is prepared in Altair Hyper mesh for solving the motion analysis. Virtual Analysis is carried out in Radioss to check the displacement acting while digging of bucket what is the effect at the lower arm and how to remove unwanted material for lower arm is carried out using Altair Optistruct. The model is Meshed with the hexapenta mesh using Altair Hyper mesh. Below figure shows complete assembly component is All Rights Reserved 538

5 Fig 6: 3D model Side view which is meshed using Hyper mesh Fig 7: 3D model Zoom view which is meshed using Hyper mesh Material Collector Fig 8: Excavator Material is Steel Fig 9: Excavator Steel Material Mechanical All Rights Reserved 539

6 Fig 10: Excavator Arm Control Coupler is highlighted Fig 11: Excavator Bucket is highlighted Fig 12: Excavator Lower Arm is highlighted for updating PSOLID All Rights Reserved 540

7 Constraints: III. BOUNDARY CONDITIONS Fig 13: Excavator Lower Arm is fixed at the coupler of Bucket in All DOF Motion: Here in this thesis we are solving Multi Body Simulation analysis this is also called as transient analysis which is related to time dependent problem. Time input is mentioned in above figure is 1second, for 1 second excavator motion is carried out and checked for displacement value for the motion. Type of analysis is mentioned in above figure is Transient. Fig 14: Excavator is solved for MOTION which is mentioned in load collector For Kinematic analysis we need to apply the joints at particular location based on the moments of excavator. Joints applied are shown below for reference. Fig 15: Joints are applied for Excavator for Kinematic (Revolute and Translate Joints) Excavator is solved for MOTION, for which joints are applied in above figure clearly shown at what location revolute and translate joint is applied. Joints applied using Hyper mesh, which will be available in 1D page. We have all varieties of joints in 1D-Page Joints which are shown below for All Rights Reserved 541

8 Fig 16: Joints are applied for Excavator using 1D Page in Hyper mesh Fig 17: Number of nodes and Elements shown in Hyper mesh Fig 18: Multi Body Simulation is solved using Altair Radioss Solver Save the particular model is a directory and click on Radioss on right side which is executing button to start the analysis of Multi Body Simulation. After results getting completed the window shows that the job is completed then we need click on Hyper view executing button as per above figure and then Post processing window will be opening in another window. In that we can see the displacement of excavator and motion of excavator. Weight of complete assembly and Lower Arm is shown below which is measured before optimization of Lower Arm model. Fig 19: Weight of Complete Excavator Design which is about 1888 All Rights Reserved 542

9 Fig 20: Weight of Lower Arm Design which is about 343 tons. After seeing the results of first model then as per the objective of the thesis we need to remove unwanted material from Lower arm which is very important to reduce the weight and it should be more stiffer because when excavator lift or dig the load will more at the lower arm location for that purpose. To get stiffest structure shape we choose the Optistruct software for getting innovative shape for lower arm. After getting the results will compare the results of optimization model weight and displacement. IV. OPTISTRUCT PROCEDURE Optimization Increases competitiveness through product innovation Provides an easy-to-use graphical user interface and tight application integration that maximizes end-user efficiency Leads the industry with the ability to solve the largest, most complex optimization problems. First- in-industry, innovative method, allows for the multi-disciplinary optimization of designs with non-linear behavior and system-level multi-body dynamic models. Additionally ESLM can be applied to concept design synthesis and design fine-tuning. The same method is used for Lower Arm of excavator design and solved using Equivalent Static Load Method, for which we need to give inputs in Optistruct deck. Procedure for deck preparation in Optistruct is shown below: Fig 21: User profile in Hyper mesh Window The first step to start the optimization deck preparation, change the user profile to Optistruct and in that optimization template will generated at the background of hyper mesh and then application of optimization tool will be available in analysis page optimization in which various different optimization techniques are available in that we are using topology optimization. This will help us to remove unwanted material based on the loading All Rights Reserved 543

10 Fig 22: Topology Optimization Setup In the above figure topology optimization option is selected and in that we need to give design variable name is required which we have mentioned L-Arm_Toplogy and then slected PSOLID as a element property which we have selected is lower arm. Fig 23 : Weight Optimization is mentioned in the response After that next step is to give a response for the Lower Arm model by which it will do internally iteration by iteration for the given response optimization will be generated a new shape to us. Fig 24: Volume fraction Optimization is mentioned in the response for Lower Arm Fig 25: Volume fraction Optimization is mentioned in the DCONSTRAINT is about 0.5(50%) The value which we mentioned in the upper bound is nothing but percentage of volume which should be removed from the model. Fig 26: Objective for Lower Arm in Optimization to minimize or maximize the All Rights Reserved 544

11 By all the above steps optimization steps are completed now directly will go to Analysis page and then to solve Optistruct we need to select Optistruct from analysis page and click on executing button of Optistruct. It will solve the problem as per the given inputs in above steps; this will take few minutes to solve the problem which will be doing by iteration process. All the results of modified model and base model results are shown in Results chapter. Results and Discussions Base model is carried out using Altair Radioss software which is solved the same results for the base design is shown for reference. Displacement of excavator complete design is shown while kinematic in condition, that means while lower arm, boom and bucket is moving what is the displacement throught the component is checked. Fig 27: Displacement is about 2.347mm at 1 second time. Fig 28 : Stress is about 867MPA at 1 second time. Based on this results will solve the Optistruct problem for Lower Arm design because if we observe the results as shown above there is no maximum displacement is available at Lower Arm. There is chance to reduce the extra material for Lower Arm component by using Optistruct technology. Optistruct is carried out especially for Lower Arm and the results are shown below for optimization results. Base model is carried out using Altair Optistruct software to get less weight and stiffest component. Post processing we are using Altair Hyper view software where will get the displacement And ISO view for Optistruct results. ISO view of base model results is shown below for All Rights Reserved 545

12 Fig 29: Hyper view window to see the displacement and ISO View of Lower Arm Fig 30: Optimization of Lower Arm ISO View Image After seeing the results of ISO view this model shape should be designed in cad or hyper mesh itself. In Hyper mesh OS Smooth tool is available it will generate the OS Smooth optimized shape which we got for Optistruct analysis. New design is generated using internal tool of hyper mesh which is called as OS Smooth, by which will get a new shape. In which it has been removed the unwanted material from the Lower Arm. The same model is shown below after OS Smooth option. Fig 31: OS Smooth Model By which meshing will remain same and no need of meshing again to the component directly for the same loading conditions of base model about 1 second we are solving multi body simulation to check the displacement of optimized model is carried out. Fig 32: For OS Smooth Model Radioss is used for MBD simulation about 1 All Rights Reserved 546

13 Fig33: Displacement is about 2.348mm at 1 second time for Second Design Fig 34: Stress is about 987MPA at 1 second time for Second Design Fig 35: Number of nodes and elements for design 2 Nodes are about and elements are The same way for the first design is about nodes and elements are If we compare the weight of the design1 and design will get the difference, first design weight is about total model weight is 1888 tons. Only for Lower Arm of first design is about tons. For the new design 2 complete weight of the model is about 1857 tons and for Lower Arm weight is about All Rights Reserved 547

14 Fig 36 : Optimized Complete Design model weight is about 1857 tons Fig 37: Optimized Lower Arm Design model weight is about tons Finally results are shown for first base design 1 and optimized model design 2, all are got concluded in next chapter. comparison of weight, displacement, stress is compared in chapter conclusions. Stress and Displacement comparison Of Two Models: Table1: Stress and Displacement comparison of base model and optimized model. BASE MODEL LOAD CASE OPTIMIZED MODEL LOAD CASE Displacement for Design mm Displacement for Design mm Stress for Design1 867 MPA Stress for Design MPA WEIGHT REDUCTION AND COMPARISON OF LOWER ARM MODEL Table 2: Weight comparison of base model and optic model of Lower Arm MODEL TYPE Weight Of The Lower Arm Base Model tons Optimized Model Percentage of Verification / * % Reduction 9.28% of weight is reduced from the base model and it is stiffer. As comparison of stress and displacement, stress of first design of excavator is 12% is increased compare to design 2 model. Stress value is beyond the yield point of material, so design is safe. Displacement is increased 1% from the original design of excavator. V. CONCLUSION In this paper, topology optimization approach is presented to create an innovative design of an excavator Lower Arm. Final comparison in terms of weight and component performance illustrates that structural optimization techniques are effective to produce higher quality products at a lower cost The Lower Arm has further undergone weight reduction using the material selection through the usage of ALTAIR RADIOSS SOFTWARE. 9.28% of weight is reduced from the base model and it is stiffer. As comparison of stress and displacement, stress of first design of excavator is 12% All Rights Reserved 548

15 increased compare to design 2 model. Stress value is beyond the yield point of material, so design is safe. Displacement is increased 1% from the original design of excavator. 1. Excavator Design is solved to get less weight component of Lower Arm. 2. Lower Arm is used as design area for getting new shape for that particular model and solved after that we achieved a new design which is shown in above chapter. 3. Finally we achieved the weight reduction for Lower Arm design, by Optistruct software the weight is reduced compare to first design and new design model. 4. Weight reduction by 9.28% 5. Displacement is increased by 1% when we compare for first design model. 6. Stress Value is more for second design, stress value is increased about 12% when we compare to base model results. Finally the second design is suitable which is having same stiffness after removing material also, the stress value is increased 12%. The value of stress is not crossed the yield point of applied material. The first and the second design are safe according to maximum stress and displacement. But aim of the project is to get the less weight of Lower Arm. So we achieved by using latest technology. REFERENCES 1. J. Koivo, M. Thoma, E. Kocaoglan and J. Andrade-cetto, Modeling and Control of Excavator Dynamics during Digging Operation, Journal of Aerospace Engineering, American Society of Civil Engineering (ASCE), Vol. 9 No. 1, pp 1-9, Bhaveshkumar P. Patel, Dr. J. M. Prajapati, Evaluation of Bucket Capacity, Digging Force Calculations and Static Force Analysis of Mini Hydraulic Backhoe Excavator, Machine Design The Journal of Faculty of Technical Sciences, Serbia, Vol. 4, No. 1, pp.59-66, Daqing Zhang, Qinghua He, Peng Hao and HaiTao Zhang, Modeling and Controlling for Hydraulic Excavator s Arm, 22nd International Symposium on Automation and Robotics in Construction ISARC 2005, 4. Ferrara (Italy), 2005, pp Forestry Earthmoving and Excavator (FEE) Statistics Committee, 5. Forestry, Earthmoving and Excavator Statistics Program, Product Definitions and Reporting Classification Methods, A Report, pp. 1-5, Hongnian Yu, Yang Liu and Mohammad Shahidul Hasan, Review of Modelling and Remote Control for Excavators, International Journal of Advanced Mechatronic Systems, Vol. 2, Nos. 1/2, pp , John J. Craig, Introduction to Robotics Machines and Control. 2nd Ed., New York: AddISOn-Wesley Publishing Company, 1989, ch. 1, p. 6. Frankel, (2004) 8. Development of a Haptic Backhoe Testbed, Unpublished M. Sc. thesis, Georgia Institute of Technology, Georgia, May 2004, pp P. K. Vaha and M. J. Skibniewski, Dynamic Model of Excavator, 9. Journal of Aerospace Engineering, American Society of Civil Engineering (ASCE), Vol. 6 No. 2, pp , P. Yang, S. Wang, J. Chiang and C. Wang, The Adaptive Control Applied to the Analysis of the Excavator Dynamics, in Conf. Rec IEEE 3rd Int. Conf. Innovative Computing Information and Control, pp. R. K. Mittal and I. J. Nagrath, Robotics and Control, Ninth Reprint, All Rights Reserved 549