Design Analysis & Topology Optimization of Passenger Car Disc Brake

The disk brake may be a device for slowing or stopping the rotation of a wheel. Generally repetitive braking system of the automobile cars results in heat generation during each braking event. The brake disc brake 3D model prepared by CATIA software. Finite Element modal analysis of automobile 4 wheeler disc brake is performed to determine mode shapes and natural frequencies and also static analysis is performed to obtain optimized model from topology optimization technique from ANSYS 19 software. Hence, experimental testing using FFT analyzer technique (impact hammer and accelerometer) is performed to determine mode shapes and natural frequency and comparison of results with numerical results. Keyword Disc Brake, Topology Optimization, FFT Analyzer.


INTRODUCTION
The racing fans involved will surely know the importance of good brakes not just for safety but also for staying competitive. The disk brake may be a device for slowing or stopping the rotation of a wheel. A brake disc usually made from forged iron or ceramic composites includes carbon, Kevlar and silica, is connected to the wheel and therefore the axle, to prevent the wheel. A friction brake generates frictional forces as two or more surfaces rub against one another, to scale back movement. Based on the planning configurations, vehicle friction brakes are often grouped into drum and disc brakes. The main component of the braking system is the disk brake. Its performance directly affects the driving safety of the vehicle. When the vehicle is braking, the excitation frequency is close to the natural frequency of the brake disk, which will cause resonance, generate severe vibration & noise & affect ride comfort. Therefore, it is necessary to analyses modal characteristics of disk brake. TATA Sumo 800 Lacer car disc brake was taken for experimental study purpose. The brake disc (or rotor) is that the rotating a part of a wheel's disk brake assembly, against which the restraint are applied. The material is usually gray iron, a sort of forged iron. The weight and power of the vehicle determines the necessity for ventilated discs. II.PROBLEM STATEMENT Nowadays, topology optimization technique is used for weight optimization of components which reduces material cost and manufacturing. In present research 4wheeler disc brake is to be studied under FEA to determine the optimum material removal from existing 4wheeler disc brake under existing boundary condition and also determine changes in von misses stress and deformation with tautologized model. Natural frequencies are calculated to determine the nature of mode shapes at respective frequencies III.METHODOLOGY The methodology involves the technology utilized for performing the designing and analysis of the object.
• Design of 4 wheeler disc brake • Dimension specification • Analysis of disc brake by ANSYS • Static structural analysis & Modal Analysis for mode shape. • To perform static structural analysis of disc brake under existing boundary condition to obtain deformation and von misses stress and optimized model from topology optimization. • The best optimized is to be obtained from topology optimization technique and compared to the existing model.     VI.ANALYSIS TATA Sumo 800 Lacer car disc brake is taken for analysis. After designing disc brake rotors in CATIA V5 the profiles is imported to ANSYS Workbench for further analysis such as Static structural analysis, and Modal analysis. Disc brake is fixed at one end to determine the mode shape and natural frequency.

• Modal Analysis:
Modal analysis may be a technique to review the dynamic characteristics of a structure under vibrational excitation. Natural frequencies, mode shapes and mode vectors of a structure may be determined using modal analysis.

Different Mode Shapes:
The modal frequencies of the first five steps and modal shapes of each order shown in below figures:-Mode shape 1 Mode shape 2 Mode shape 3 Mode shape 4 Mode shape 5 Frequency at Nodes

Fig.9 Different Mode Shapes
In above figures different mode shapes are plotted with respective natural frequency so, it is observed the mode shape pattern also change with respective frequency so maximum frequency is observed around 1446 N. In above analytical calculation (A) pressure acting on pad is calculated as 2.29 MPa but design is for maximum condition so standard equation to calculate pressure on pad is given below From paper mentioned standard equation is So, pressure on rubber pad is 4 MPa on both sides are applied. So, we have 4 MPa and 2.29 MPa as per design. It is beneficial to use 4 MPa as design should sustain extreme pressure due to fluctuation of motion on disc brake.
• Boundary Condition: It is observed that maximum deformation is 0.0108 mm.

Fig. 12Equivalent Stress Results
Maximum stress observed is 16 MPa VII.TOPOLOGY OPTIMIZATION Topology optimization could also be a mathematical approach that optimizes material layout within a given design area, for a given set of loads and boundary conditions such the resulting layout meets a prescribed set of performance targets. Basic Theory There are three types of structure optimization, • Size optimization • shape optimization • Topology optimization Three optimization ways in which correspond to the three stages of the merchandise design methodology, significantly the detailed design, basic design and conceptual design. Size optimization keeps the structural form and topology structure invariant, to optimize the varied parameters of structure, like thickness, section size of beam, materials properties; shape optimization maintains the topology structure, to vary the boundary of structure and form, explore for the foremost applicable structure boundary scenario and shape; topology optimization is to hunt out the foremost effective path of materials distribution throughout never-ending domain that meet the displacement and stress conditions in structure, produce a specific performance optimum. Thus, compared to size and shape optimization, topology optimization with more freedom degree and bigger design area, its greatest feature is below unsure structural form, keep with the well-known condition and a given load to work out a budget structure, every for the abstract sort of recent product and improvement design for existing product, it is the foremost promising side of structural optimization. For continuous structure topology optimization, there are some mature ways like: uniform technique, evolutionary structural optimization technique, variable density technique etc. Uniform technique introduced cell structure of micro structure (unit cell) at intervals the weather of the structure, each unit has three forms, significantly non-material voids (size = 1), isotropic-material entity medium (size = 0) and orthotropic-material opening-hole medium (0 < size < 1). whereby the distribution of every form are able to describe the shape of topology and conjointly the shape of structure; evolutionary structural optimization technique believe that stress in any elements of the structure should beneath the identical level in a perfect structure thus you will be able to delete the fabric artificially. Thus bit by bit remove material that in a very low stress state, then delete the update rate, thus optimized structure becomes more uniform. Variable density technique is employed to conduct optimization throughout this paper.

VIII. EXPERIMENTAL TESTING
The experimental validation operation is finished by using FFT Operation testing (Fast Fourier Transform) analyzer. The FFT spectrum analyzer samples the input , computes the magnitude of its sine and cosine components, and displays the spectrum of these measured frequency components. The advantage of this system is its speed. Because System operation FFT spectrum analyzers measure all frequency components at identical time, the technique offers the likelihood of being persistently faster than traditional analog spectrum analyzers. This analysis will be expressed as a series operation. The fast Fourier transform could be a method of operation mathematical method for transforming a function of your time into a function of frequency. Sometimes it's described as system transforming from the time domain to the frequency domain. it's very useful for all method analysis of time-dependent.

FFT analysis
FFT is one main property in any sequence getting used generally. To find this property of FFT for any given sequence, many transforms are being employed. the most important issues to be noticed find this property are the time and memory management. Comparison is finished between the 2 algorithms with relevance the memory and time managements and therefore the better one is pointed. Comparison is between the two algorithms written, considering the time and memory because the sole main constraints. Time taken by the 2 transforms find the basic frequency is taken. At the identical time the memory consumed while using the 2 algorithms is additionally checked. Supported these aspects it's decided which algorithm is to be used for better results.

IX. SUMMARY
Modal analysis of hydraulic brake is performed to get different mode shapes and natural frequency of existing 4-wheeler hydraulic brake. Static structural analysis of hydraulic brake is performed to see deformation and equivalent stress. It's observed around maximum deformation is 0.0108 mm and equivalent stress is 16.76 MPa. It's concluded that the region indicated in the pit in topology optimization provides information regarding removal of material from that area it's about 55.53% to original mass.