Design and Analysis of Crankshaft Using Topology Optimization in ANSYS

1. INTRODUCTION

The crankshaft is a moving part of the internal combustion engine (ICE). It‘s main function is to transform the linear motion of the piston into rotational motion. The pistons are connected to the crankshaft through the connecting rods. The crankshaft is mounted within the engine block. The crankshaft is fitted into the engine block through its main journals. The connecting rods are fixed on the conrod journals of the crankshaft. On opposite sides of the conrod journals the crankshaft has counterweights which compensates outer moments, minimizes internal moments and thus reduces vibration amplitudes and bearing stresses (Reddy, et. al., 2017). In the present work, one crank throw model was used to calculate the static strength of crankshaft. Software based analysis techniques use multi-body simulation tools for accurately predicting the operating loads acting on the engine components. The 3D model of crankshaft system, obtained from CATIA V5 software is analyzed in Ansys Software to assess the motion and loads acting on the crankshaft.

For the design optimization process of crankshaft further topology optimization technique of Ansys is used to remove the unnecessary material from the crank shaft.

Unless it has been topologically optimized, every part in an assembly probably weighs more than it needs to. Extra weight means excess materials are being used, loads on moving parts are higher than necessary, energy efficiency is being compromised and shipping the part costs more. Now, with Topology Optimization technology, ANSYS Mechanical gives you the tools you need to design

minimum material thicknesses are set and exclusion areas are defined (Pandiyan, et. al., 2016). Topology optimization in ANSYS Mechanical allows you to: • Take into account multiple static loads combined with optimizing for natural frequencies (modal analysis) • Satisfy requirements for minimum material thickness • Observe rules around feature direction (for machining operations for example) • Have scope for both cyclic and planar symmetry • Easily validate results

In this modelling section 1 basic model and 3 implement model is proposed. The crankshaft model 3D geometry is created by using CATIA V5 and then it is import in ANSYS 19.0. and check all the result in three different load case 22624N, 32624N and 42624N.

mechanical property are used in ANSYS are shown in table below:

Material Forget steel Density (Kg/m3) 7833 Young‘s Modulus (MPa) 2.21E+05 Poisson‘s Ratio 0.3

After applying meshing 26641 nodes and 19234 elements is generated in crankshaft.

The FE model created was subjected to static structural analysis after assigning suitable material properties and boundary conditions. The force acting on the crankpin for case-1 due to gas loads at 4500 rpm. The maximum force acting on the crankpin is 22624 N.

The force acting on the crankpin for case-2 due to gas loads at 4500 rpm. The maximum force acting on the crankpin is 32624 N.

The force acting on the crankpin for case-3 due to gas loads at 4500 rpm. The maximum force acting on the crankpin is 42624 N.

The crankshaft is fixed in both the end of shaft.

Case-1 (Model -1) In this case the maximum force acting on the crankpin is 22624 N.

In this case 0.011156mm deformation is found.

Fig.9 represents the model 1of total deformation in case 1 when the maximum force acting on the crankpin is 22624 N. in this model min. deformation is 0 and max. deformation is 0.011198.

In this case 68.42 Mpa maximum stresses is found.

Fig.10 elaborates the mode 1 of equivalent stress in case 1 when the maximum force acting on the crankpin is 22624 N. In this model min. stress is 0.0018211 and max. stress is 68.42. The ANSYS 19.0 provide the feature of topology optimization. After applying 22624N force the new model is proposed. The red region show that this material is does not affect the all over stress value. So all the new design is made only change in red region.

In this case 0.011182mm deformation is found.

Fig.12 shows the model 2 of total deformation in case 1 when the maximum force acting on the

In this case 68.70 Mpa maximum stresses are found.

Fig.13 represents the model 2 of equivalent stress in case1 when the maximum force acting on the crankpin is 22624 N. in this model min. stress is 0.0015045 and max. stress is 68.703.

In this case 0.011202mm deformation is found.

Fig.14 shows the model 2 of total deformation in case 1 when the maximum force acting on the crankpin is 22624 N. In this model min. deformation is 0 and max. deformation is 0.011202. Case-1 (Model-3)

In this case 63.49 Mpa maximum stress is found.

Fig.15 represents the model 3 of equivalent stress in case 1 when the maximum force acting on the crankpin is 22624 N. In this model min. stress is 0.0068849 and max. stress is 63.492.

In this case 0.011207mm deformation is found.

Fig.16 shows the model 4 of total deformation in case 1 when the maximum force acting on the crankpin is 22624 N. In this model min. deformation is 0 and max. deformation is 0.011207.

In this case 4 74.156 Mpa maximum stress is found.

Fig.17 shows the model 4 of equivalent stress in case 1 when the maximum force acting on the crankpin is 22624 N. In this model min. stress is 0.0083383 and max. stress is 74.156. Case-2 (Model-1) In this case the maximum force acting on the crankpin is 32624 N.

In this case 0.016144mm deformation is found.

Fig.18 shows the model 1 of total deformation in case 2 when the maximum force acting on the crankpin is 32624 N. in this model min. deformation is 0 anjd max. deformation is 0.016144.

In this case 98.68 Mpa maximum stress is found.

Fig.19 shows the model 1 of equivalent stress in case 2 when the maximum force acting on the crankpin is 32624 N. in this model min. stress is 0.0026254 and max. stress is 98.638.

In this case 0.016136mm deformation is found.

Fig.20 represents the model 2 of total deformation in case 2 when the maximum force acting on the crankpin is 32624 N. In this model min. deformation is 0 and max. deformation is 0.016136.

In this case 108.57 Mpa maximum stress is found.

0.0021071 and max. stress is 106.57.

In this case 0.016149mm deformation is found.

Fig.22 shows the model 3 of total deformation in case 2 when the maximum force acting on the crankpin is 32624 N. In this model the min. deformation is 0 and max. deformation is 0.016149.

In this case 91.533 Mpa maximum stress is found.

Fig.23 shows the model 3 of equivalent stress in case 2 when the maximum force acting on the crankpin is 32624 N. in this model min. stress is 0.012809 and max. stress is 91.533.

In this case 0.057078mm deformation is found.

Fig.24 shows the model 4 of total deformation in case 2 when the maximum force acting on the crankpin is 32624 N. In this model min. deformation is 0 and max. deformation is 0.057078.

In this case 176.84 Mpa maximum stress is found.

Fig.25 shows the model 4 of equivalent stress in case 2 when the maximum force acting on the crankpin is 32624 N. In this model min. stress is 0.022639 and max. stress is 176.84. Case-3 (Model-1) In this case the maximum force acting on the crankpin is 42624 N.

In this case 0.02109mm deformation is found.

Fig.26 elaborates the model 1 of total deformation in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. deformation is 0 and max. deformation is 0.02109.

In this case 128.86 Mpa maximum stress is found.

Fig.27 shows the model 1 of Equivalent stress in Case-3 when the maximum force acting on the crankpin is 42624 N. In this model min. stress is 0.0034299 and max. stress is 128.86.

In this case 0.021079mm deformation is found.

Fig.28 show the model 2 of total deformation in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. deformation is 0 and max. deformation is 0.021079.

In this case 148.83 Mpa maximum stress is found.

Fig.29 model 2 of equivalent stress in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. stress is 0.0027527 and max. stress is 141.83.

In this case 0.021096mm deformation is found.

Fig.30 shows the model 3 of total deformation in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. deformation is 0 and max. deformation is 0.021096.

In this case 119.57 Mpa maximum stress is found.

Fig.31 shows the model 3 of equivalent stress in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. stress is 0.016733 and max. stress is 119.57.

In this case 0.074564mm deformation is found.

Fig.32 shows the model 4 of total deformation in case 3 when the maximum force acting on the crankpin is 42624 N. in this model min. deformation is 0 and max. deformation is 0.074564. Case-3 (Model-4)

In this case 231.01 Mpa maximum stress is found.

Fig.33 shows the model 4 of equivalent stress in case 3 when the maximum force acting on the crankpin is 42624 N. In this model min. stress is 0.029575 and max. stress is 231.01.

After performing analysis in ansys following deformation are found as shown in table.

Graph 1 shows the comparison of deformation. In this deformation analysis there are three cases used for every four model. In this graph shows the model 4 deformation is high in case 2 and case 3. In case 1 the deformation of all model is close to each other.

After performing analysis in ansys following Stresses are found as shown in table.

Graph 2 represents the comparison graph of stress. In this stress analysis research three case used for every four model. In every case model 4 stress is very high and model 3 stress is low.

After performing analysis in ansys following Weight are found as shown in table.

is lower.

Based on these analysis results, concepts have been developed which reduce the weight of the crankshaft to a possible extent, without affecting the performance of the engine. The 3D model of crankshaft system, obtained from CATIA V5 software is analyzed in ANSYS to assess the motion and loads acting on the crankshaft. Topology optimization is help to optimize the performance of any machine. The crankshaft model 3D geometry is created by using CATIA V5 and then it is import in ANSYS 19.0. and check all the result in three different load case 22624N, 32624N and 42624N.

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Associate Professor, Department of Mechanical Engineering, Sagar Institute of Science and Technology Bhopal