Dynamic Analysis of an Automobile Lower Suspension Arm Using Experiment and Numerical Technique (original) (raw)
Related papers
Identification of Dynamics Modal Parameter for Car Chassis
IOP Conference Series: Materials Science and Engineering, 2011
This paper explores and investigates the dynamic characteristics of car chassis structure by using experimental modal analysis (EMA) method and modal testing. Dynamic characteristics are divided into three parameters include natural frequency, damping factor and mode shape. In this study, modal testing was performed on the car chassis including the impact hammer and shaker test. Data analyzer was used to convert the response signal from the sensor, which was in the time domain to frequency domain. Result obtained from both methods, is compared on each axis (X, Y and Z axis). However, small discrepancy was observed in terms of natural frequency, which is within the range of 5%. Based on the results, interpretation and comparison were made for both methods.
Modal Analysis of Lightweight Racing Car
DEStech Transactions on Computer Science and Engineering
The article deals with modal analysis of light racing car. The objective of the modal analysis was to obtain a mathematical model of the structure that matches as closely as possible to the experimental results achieved in the tests. The post-processing stage encompasses the use of the results to update theoretical predictions, optimization via structural modification, subsystem coupling, calculation of real modes from complex modes, etc. So, modal analysis has been used as a simple way to calculate the natural frequencies of the system and as the technique for finding out, which frequencies can be destructive and dangerous for it. Within the article, the verification of boundary conditions of virtual FEM analysis was done using the experimental modal analysis. It was performed on a simple fixed beam. After the results comparison, it could be stated that the values of natural frequencies correspond each other, so the virtual lightweight racing car could be analyzed in software Autodesk Inventor Professional. The analysis has helped to improve the stiffness of the car to be more stable on the wavy surface of the racing road.
Vibration Analysis and Improvement of a Vehicle Chassis Structure
Product development cycle time is very important in automotive industry which is very competitive nowerdays. New products are introduced into the market with better designs in short period of time by carrying out different engineering analysis. This study is focused on analyzing the existing chassis design and the noise, vibration and harshness(NVH) characteristics are studied. Modeling of chassis structure is carried out using 3D modelling package CATIA V5 and finite element model is created by meshing using Hypermesh software. The main objective is to find the natural frequency and analyse the mode shape of the automotive chassis structure. Results of the analysis will help to study the dynamic behavior of the chassis structure with load application/real road condition and to improvise the car chassis structure assembly. Introduction Serious pressures to shorten product development cycles, to broaden the spectrum of vehicles, to develop and produce new product more efficiently, characterizes the automotive industry. By integrating a higher number of functions and features, automotive systems have become more complex. Thus the use of numerical simulation in vehicle development is enforced due to increasing material costs and also rising effort due to a higher number of exigencies on the vehicles. This called for a multidisciplinary study; starting from classical disciplines like driving simulation, structural static analysis and crashworthiness analysis to additional features such as interior and exterior acoustics, electromagnetic compatibility. In the last two decades, the numerical simulation via finite element methods (FEM) has been well integrated into the product development process (PDP) of the automotive industries. The PDP is currently increasingly driven by numerical simulation as non-linear (such as crash-worthiness) and linear cases (such as NVH) are been accomplished. One of the most important attributes for car product development is noise, vibration, and harshness (NVH). NVH response can be classified in various ways: power-train NVH, road noise, wind noise, component noise, and squeak and rattle. Vibrations are produced when there is an exciting (or compelling force) acting upon an object, causing the body to vibrate. Eliminating an NVH concern is greatly assisted by locating the compelling force (the source of the vibration). The major component groups that produce compelling forces are tire and wheel, driveline, engine and torque converter. A vehicle with a good NVH behavior often results in a much higher customer satisfaction. In vehicle development, different NVH models are used for different systems and purposes that will assure quality of the NVH behavior. In practice, nearly all vibration problems are related to structural weaknesses, which is associated with resonance behavior (natural frequencies excited by operational forces). The complete dynamic behavior of a structure (in a given frequency range) can be viewed as a set of individual modes of vibration, each having a characteristic natural frequency, damping, and mode shape. Problems at specific resonances can be examined and subsequently solved by using these modal parameters to model the structure.
In this paper, concept of experimental modal analysis is discussed to derive dynamic properties of mechanical structures and equipments. Dynamic properties (mode shape, damping, and resonant frequencies) are calculated using MATLAB program. Amongst present curve fitting method, Rational Fraction Polynomials (RFP) method is used in the derivation of modal parameters. Results obtained from this method are compared with those obtained form experiment and shown in form of standard deviation. This standard deviation is computed from different experimental FRF values and analytically obtained FRF values. 1. Introduction Vibration has many undesirable and harmful effects on life and performance of mechanical equipments and other structures. The effects of vibration are due to dynamic interaction between vehicles and bridges, structural motions due to earthquakes, noise generated by construction equipment , vibration transmitted from machinery to its supporting structures thereby interfering with their performance , damage as well as malfunction and failure due to dynamic loading, fatigue failure, oscillation of transmission lines[1]. The objective of this paper is to emphasis on dynamic analysis of such equipments and structures by capturing their actual dynamic behaviour during experimentation such that the adversity arising from vibration effects can be minimised to improve their life and performance. Dynamic analysis consists of experimental and operational modal analysis. In experimental modal analysis (EMA), structures are artificially excited by exciters (Impact hammers and shakers). In operational modal analysis (OMA), structure is analysed while it is operated upon. For large and heavy structures (civil structures such as bridge and dams), modal analysis is used to detect damage by ambient (traffic) condition [2] .Recent trends in dynamic analysis are extremely focused on better performance and life of structures. Self excited vibrations of tool result in unstable cutting process, poor surface finish, reduced productivity and damage on the machine itself. By considering spindle geometry (its diameter and length), bearing stiffness, tool holder geometry and selection of combination of depth of cut and spindle speed from stability lobe diagrams, machining operation can be made chatter free[3,4]. In vibration of rotating equipments (such as pump, turbine etc.), dynamic analysis is used to check their health as excessive noise of these equipments is experienced by personnel in large power plants and refineries due to damage or failure of seals [5]. 2. Methodology In this paper, EMA is focused upon. EMA is used to characterize resonant vibration in machinery and structures. In EMA, a mode of vibration is defined by three parameters; modal frequency, modal damping and mode shape. Modal parameter estimation is the process of determining these parameters from experimental data. Furthermore, a set of modal parameters can completely characterize the dynamic properties of a structure. This set of parameters is also called a modal model for the structure. Modes (or resonances) are inherent properties of a structure. 199
Vehicle Modeling for High Frequency Vibration
2021
Numerous experiments have shown that the wheelset-track noise can be transferred by the vibration through the primary suspensions to the bogie, which is called "structural-borne sound". The high frequency vibration transfer characteristics of primary suspensions, such as helical springs, arm bush and damper, is important. In this paper, a vehicle-track coupling dynamic model was developed considering high frequency vibration transferred by the primary suspensions. Based on the 3D finite element method, the modes of the bogie were simulated and a model of flexible bogie was established using mode superposition method. The 3D FE method was also used to develop the helical springs' simulation model. Based on the tests' result, the model of arm bush was established using transfer matrix method. Laboratory and field tests were carried out to validate the developed model. Short wavelength irregularities were adopted to excite the system to analyse the different influence on the structural-borne sound transfer characteristics. The results show that the vibration transmission rate is larger in 600-1000 Hz, which agrees with the test results. The model lays a foundation for analysing the sound transmission of structures.
Stress Analysis And Modal Transient Response Of Car Chassis
2009
This paper discusses the computational modal transient response and stress analysis of car chassis. The prediction of the dynamic properties of the chassis is great significant to determine the natural frequencies of the structure. In order to avoid resonance, value operating frequency must lower than natural frequency of the chassis. Stress analysis was carried out by using Algor FEMPRO Software to determine the stress distribution on the chassis structure when load been applied. Result shows that bending mode observe at first mode frequency, torsion mode at second mode frequency , mixed bending and torsion at third mode frequency and bending mode at fourth mode frequency. Range natural frequency from 50-99 Hz was examined on this analysis. Maximum stress, 45 MPa was determined at each corner at pillar joint and this value is under the allowable stress for steel which is 300 MPa. The stress and modal analysis techniques are significant essential for automotive chassis structure design.
MODAL ANALYSIS OF TWO WHEELER CHASIS
The frame is an important part in a Two Wheeler and it carries the load acting on the vehicle. So it must be strong enough to resist the shock, twist, vibration and other stresses. In vehicle frame different types of failure occur due to static and dynamic loading conditions. Natural frequency, damping and mode shapes are the inherent structural properties and can be found out by experimental modal analysis. Experimental Modal analysis (EMA) is the process of determining the modal parameters of a structure for all modes in the frequency range of interest. The objective of this study is to determine the natural frequencies, damping and mode shapes of the both chassis of two wheeler namely as Pulsar 150cc and Passion by using experimental modal analysis. Our goal is to minimize the effect of these vibrations, because while it is undesirable, vibration is unavoidable. The dynamic characteristics of the two wheeler chassis such as the natural frequency and mode shape will determine by using finite element (FEM) method.
Modal analysis on tire with respect to different parameters
Alexandria Engineering Journal, 2016
This paper presents experimental modal analysis of non-rotating tires under different boundary conditions. A test rig with four guides in vertical (radial) direction and two guides in axial direction was designed to support the tire-rim assembly with a free support. The setup permits to carry out the experiments on the grounded supported tire-rim assembly while changing the value of the static load acting on the wheel axis. Under static load condition, it is found that, tire deflection depends on the applied static radial force in a hysteresis manner and a third-order polynomial was used to fit the data during loading and unloading conditions. The relationship between static stiffness in radial direction and tire deflection is nonlinear and depends on loading/unloading conditions for different tire pressures. The response of the tire is quite similar to the response of viscously damped mass system for impulse force which is provided by an impact hammer. The results show that the system modal parameters can be obtained respective of loading or unloading conditions with a maximum difference of 1.992% for frequency values and 3.66% for damping values. This study has a practical value for the description of mechanical properties of tires.