Analysis Of Vehicle Air Compressor Mounting Bracket Murtaza Goawala 1,Rahul Giri 2,Niket Phalke 3,Krishna Singh 4,Prof. Nitin Sall 5 1,2,3,4,5 Automobile Engineering Dept., Theem College Of Engineering, Abstract The requirement of light weight material is increasing in the Automotive industries. Light weight materials are required for influencing parameters such as cost of the vehicle and fuel efficiency. In this paper, the use of analysis technique is used for static structural analysis and modal analysis for comparing different materials. For modal analysis damping is not considered for finding the natural frequency. The materials used are Aluminium Alloy, Magnesium Alloy and Grey Cast Iron. Keywords Compressor mounting bracket, Static Structural & Modal analysis, Natural frequency. I. INTRODUCTION In automotive air conditioning system the compressor plays a very important role. It is attached to the engine via a mounting bracket and therefore the compressor mounting bracket is exposed to the heaviest vibration conditions. Because of heavy vibrating loads and need for reducing weight, the compressor mounting bracket is one of the most important parts that require optimum structural design. There are certain problems regarding the mounting bracket, such as design space issue, material used. Reducing the weight of the vehicle is the most effective way for increasing the automobile efficiency and decreasing the emissions. The compressor mounting bracket is shown in Fig.1. Figure 1. Compressor mounting bracket II. DESIGNING OF COMPRESSOR BRACKET From the reverse engineering data, the component is modeled in commercially available modeling software. The software used for this purpose was AutoCad 2017. The generated CAD model is shown in Fig.2 DOI : 10.23883/IJRTER.2017.3063.TWM7Z 174
Figure 2. CAD model of compressor bracket III. FEA ANALYSIS OF COMPRESSOR BRACKET Finite element analysis (FEA) is one of the most popular engineering analysis method. FEA requires a finite element mesh as a geometric input. The compressor mounting bracket is made up of Aluminium Alloy or Magnesium Alloy or Grey C.I. The simulation is done for comparing these three materials. 3.1. Meshing A uniform tetrahedral mesh is generated by using Ansys 2017. The size of the element selected was 3mm.The Mesh model is shown in the Fig.3 Figure 3. Tetrahedral mesh of compressor bracket 3.2. Boundary conditions and loads Fixed boundary condition was applied on the engine side support as shown in Fig.4. the total load i.e. the weight of the compressor is 4.04kg, and is applied on the compressor mounting holes as shown in Fig.4. @IJRTER-2017, All Rights Reserved 175
Total load on the compressor bracket = 4.04 x 9.81 = 39.6324N. This load is supported by two holes therefore the total load is divided equally between the two holes. Load at each hole = 39.6324/2 = 19.8162N. 3.3 Results Figure 4. Boundary conditions Figure 5. Total deformation of Aluminium Alloy @IJRTER-2017, All Rights Reserved 176
Figure 6. Equivalent (von-mises) stress of Aluminium Alloy Figure 7. Mode shape for lowest natural frequency of Aluminium Alloy @IJRTER-2017, All Rights Reserved 177
3.3.1. Comparision of different materials Sr. No. International Journal of Recent Trends in Engineering & Research (IJRTER) Material Table 1. Different materials comparision Total Deformation (mm) Results Max. Equivalent (von-mises) stress (MPa) Natural Frequency (Hz) 1 Al alloy 1.1126e-004 0.55767 3515.9 2 Mg alloy 1.73e-004 0.51631 3323 3 Grey C.I. 7.6983e-005 0.72595 2593.2 IV. CONCLUSION Vibration plays a very critical role in compressor component, especially in the supporting bracket. As we know that Grey C.I is a brittle material and it results in low natural frequency and so it will prove hindrance in vibration characteristic of the bracket. Also from above result we see that Al alloy and Mg alloy are having natural frequency in close range and indicate that any one of them would be a better choice for fabrication of compressor mounting bracket over Grey C.I. However in this analysis we have not considered damping characteristics. In general Mg alloy shows better damping characteristics and hence, as far as possible Mg alloy will be preferred. REFERENCES 1. Umesh S. Ghorpade, D.S. Chavan, Fininte Element Analysis And Natural Frequency Optimization Of Engine Bracket, International Journal Of Mechanical and Industrial Engineering (IJMIE) ISSN No. 2231-6477, Vol-2,2012. 2. Phuspendra Mahajan, Abhijit L. Dandavate, Analysis and Optimization of Compressor Mounting Plate of Refrigerator using FEA, International Journal of Emerging Technology and Advanced Engineering ISSN 2250-2459, Vol-5, Issue 5, May 2015. 3. Vyankatesh D. Pawade, Pushkaraj D. Sonawane, Dynamic Analysis of Air Conditioner Compressor Mounting Bracket, International Engineering Research Journal (IERJ) ISSN 2395-1621, Page 4825-4829, 2015. 4. Jeong Woo Chang, Young Shin Lee, Topology Optimization of Compressor Bracket, Journal of Mechanical Sience and Technology 1668-1676, 2008. 5. Vyankatesh D. Pawade, Pushkaraj D. Sonawane, Study of Design and Analysis of Air Conditioner Compressor Mounting Bracket, International Journal of Science and Research (IJSR) ISSN 2319-7064, 2013. 6. M. Venkata Raja, M. Anil Kumar, Modeling and Analysis of Mounting Plate of a Rotary Compressor, International journal of Computer Science Information and Engineering Technologies ISSN 227-4408 Issue 3 Vol. 3. @IJRTER-2017, All Rights Reserved 178