SUV car body with finite element analysis simulation

1- Draft Contents

Throughout the second section in this progress report, a full idea is presented to the reader about the aims, objectives and the need of this report. Objectives are shown clearly and summarized in 4 points.

The third section provides information about how these objectives are going to be accomplished, it describes with little details about how each step is made and describes the steps needed to obtain the required simulation of the object of interest.

Literature review related to this subject is presented in the fourth section; it comes to mentioning the results, challenges, aims, explanations and methodologies made by these papers, lectures or presentations. Even though finding reading materials that is directly connected to the subject, but the gathered information were quite useful and gave an idea about finite element analysis and simulation.

A time plan showing the progress of work and the actions that will be made in the future with the needed modification will be in the fifth section of this research.

The used references are listed in section six.

Finally, an appendix containing the initial report is presented. The changes that have been made on it through the progress report are shown clearly.

2- Research Objectives

Now days, all vehicle manufacturers use the computer aided design in order to enhance the production process and reduce cost, time and effort. Finite Element analysis is one of the tools presented by the CAD methods to help analyzing the engineering structure in all the required conditions and from all the aspects required by various divisions involved in the manufacturing process even before producing the first prototype in order to predict the static and dynamic behavior of the produced structure and try to avoid the limitation of the design as much as possible prior to the fabrication process.

The aim o the project is to examine an SUV body frame using the SolidWorks software and test it against various types of loading, road and driving maneuvers in order to obtain a new design that overcomes the limitations faced at those aspects to provide easier, safer and more comfortable driving conditions, adding to that climbing an extra step of perfection accomplishment ladder and supplying the researcher of a new type of knowledge.

From the previous paragraphs, the objectives of this project that will lead to accomplish the main aim can be summarized by the following points:

1- Make a stress, strain and deflection analysis to a pre-designed SUV body frame, Chassis or parts using SolidWorks Finite Element Analysis software.

2- Modify the tested object(s) selected in part one by re-designing it in a way that will allow it to overcome its limitation by adding parts, removing parts, increase or decrease the overall size, change the material in use, changing dimensions or by any other necessary change.

3- Test the result(s) obtained by step 2 in order to confirm the validity of the modified design, and, to be more specific, make sure that mesh size and properties are functional and applicable.

4- Put the reliability of SolidWorks under test and compare the results that been obtained for a selected part with other finite element analysis software's.

3- Methodology

Finite element analysis (FEA) is a numerical solving for a lot of partial deferential equations that represent an engineering structure. SolidWorks is CAD software that is built on the principal of FEA used to generate simulations for analytical design purposes.

The first step of the project will be selecting an SUV's body frame and/or any other vital part (from the internet or research institutions) in order to perform the stress, strain, deflection and any other required test in order to develop a full vision about the current situation of the object and determine the points which will be worked on.

In order to perform the required analysis in SolidWorks, first, a mathematical model must be built to represent the geometry. In this mathematical model, the represented geometric model must be meshable and small finite element exist within the mesh in order to solve the numerical problems involved with the mesh, along with the mathematical model, Defeaturing (removing the unnecessary dimensions), Idealization (discriminating between objects in contact) and Clean-up (modifying the quality requirements and needed option to meet specifications).

After the mathematical has been established, it is fractured into finite elements by a process called "Discretization" also known as meshing. After the model has been meshed, all loads and supports are represented and applied on the structure and a full representation including all physical and mechanical effects is generated as if it was operating in reality.

The finite element model is solved using the software's solver; this process will generate all the required data for simulating the part and giving the required predictions needed to give the designer an idea about the part's performance in practice.

The modifying process starts as soon as the status of the system is known; the parts of interest are identified usually by the red color, the highest stress area. This part or section must be reinforced by adjusting its design, adding supporting parts, changing the part's material or modifying the dimension in order to decrease the stress subjected to it, by doing this, failure may be reduced or even eliminated, product's life cycle increased and safety conditions are fulfilled. In summary, better product is produced and thus higher qualities are obtained, allowing the product to compete in the market and accomplishing higher market shares due to its higher reliability. The re-design process is performed using SolidWorks.

To ensure that the modified product meets the needed requirements and specifications, it is retested again using the same procedure mentioned earlier in this section. The process of modifying the object and simulating it again is repeated until reaching satisfactory results that makes the part/structure a better one. The methodology of this project may be represented by the following chart.

4- Literature Review

(Zamanzadeh, 2004) This study is a part of a series that will talk about the types of failure in materials; this one will talk about metallurgical failures. Failures are always caused by humans errors, according to this, errors are classified into three main categories, errors of knowledge, performance and intent. Finite element analysis is a very powerful tool in analyzing mechanical structures because it deal with the whole structure as a huge number of segments on each a mathematical solution is performed in order to know the state of each element of them, then they are summarized together to give the whole status of the structure. FEA can provide a way of evaluating all kinds of stresses, deflections, shock, bends, forces and types of loads, FEA abilities include: predicting a part's ability to hold a certain type of stress, calculate the remaining period of an element's life and determine the type of failure that is more willing to occur for the object of interest. Fracture mechanics science is involved in putting the failures due to fracture and cracks into a mathematical frame so it can be understood and explained; it relates the defect size and the crack's principal initiation to the subjected stresses and the fracture toughness of the material. "Fracture Toughness" is the stress which will cause the crack to grow after it has been initiated by stress concentration agent. The size of the defect that the material can handle without any further growth can be calculated from the equation:, this equation will allow for determination of the allowable flaw size, minimum stress required for sudden failure, applied load when failure occurs, determination of materials used in manufacturing and decide if the design of a certain component was satisfactory or not.

(Atiqullah, 2009) Finite Elements Analysis (FEA) is the mathematical representation of complex engineering problems to obtain a unique solution for each segment of the system; it can be used to obtain structural, heat transfer, static and various other engineering systems solutions. FEA is based on approximating the mechanical and physical behavior of each tiny segment of the system by a mathematical representation. This lecture talks about simple FEA for a truss (rod). A rod maybe defined as a structural member that deals only with axial stresses, its cross section is constant and it obeys the Hook's law, that is, the following equations can be applied on it:

If the truss's area A is constant, then simple analysis is made, but if A was variable, an FEA analysis must be made including the entire segments (areas) of the system, more segments means more accurate. The lecture also provides a review of linear algebra and gives a practical example. There are several quantities that must be known when design such trusses like the ultimate, yield, critical stresses and strain.

(Smith, et. al., 2003) The objectives of this presentation were to build a NASCAR chassis model and apply it to Ansys and to perform stress analysis on crash and curving. FEA programs helps manufacturers and NASCAR teams by saving money, time and lives. After that, the presentation talks about the rules and policies, present a design that applies all these rules and requirements and then perform different types of analysis and criteria to test the new chassis. The lecture concluded that the current design of the NASCAR chassis is reliable during the race or in the case of accidents; the disadvantage of it is the bending at the front of the car.

(Al-Asady, 2009) This study was conducted to compare the results obtained by the FEA and the experimental for an automotive suspension part. The part was a lower suspension arm for a 2000cc sedan car. Variable stress, strain and fatigue tests were performed on the part to obtain the critical points location, loading and part life prediction. The strain distribution obtained from experimental results was found to be compatible with the FEA relative to the complexity of the geometry of the part, but on the other hand, the data collected from the road test was very different from that obtained by FEA. The study presents models on how life expectancy and failures maybe be predicted accurately by following a certain series of procedures and applying mathematical models. The purpose of FEA was to determine the critical points on the part. CATIA simulation software was used to generate the model, MSC Nastran for strain analysis and MSC Fatigue for fatigue analysis. The study has reached for main five conclusions: In order to obtain accurate stress and strain results, loads and boundary conditions must be computed correctly and very carefully, FEA analysis must be compared with experimental data to validate it to ensure its accuracy in order to maximize their advantages in the future, Strain analysis data were reasonably correct by the FE model and helped researchers to identify the exact position where the strain gauges must be fixed, Component (part) data should be collected experimentally, Even though fatigue damage occurred at low cycles range, it was justified by the great number of the cycles.

(Cirak, et. al., 2001) The main contribution made in this paper is the presentation of "demonstration computationally a simple, theoretical and justified frame work for an integrated system and make a FE analysis of thin-shells". The employment of subdivision surfaces is presented as a basic foundation for designing, modeling and simulating as a unified reference. Usually, the process of compiling a model into a mechanical simulation or vice versa requires a lot of efforts due to the incompatibility, thus, the use of subdivision surfaces is required because it provides simple, flexible and efficient tool for arbitrary topology without the use of surface modeling which will jump over a lot of the problem that exist in the typical approaches. Subdivision method is also suitable for Finite element analysis regarding thin-shell equations which predict the behavior of the structure. The subdivision method depends on constructing smooth surfaces by repeated refinement that follows a certain control protocol; this method was first presented by Catmull and Clark in order to overcome the limitations caused by spline patches in topology surfaces models. In this study, triangular surfaces were used instead of traditional rectangles to support the aims of the study. The paper also comes to mentioning the iteration cycle of a product consists of four stages: concept, design, device and function, there is an inter-stage between design and function which is performed by the use of FEA software in order to estimate the reliability of the designed product before manufacturing. Other main results that the study has reached or proven was that the used basis functions were coincided perfectly with the FEA analysis of thin-shells, which enhanced the ability of modeling smooth surfaces with using a relatively coarse control mesh, and the presented examples proves that.

(DraškoviÄ‡, et. al., 1997) The aim of this test is to study an example of a spherical shell that has been in use for many years in monlinear finite element analysis. Tests were performed on four thin shell models to obtain central deflection, the experimental tests were conducted on specific conditions such as: a uniform normal pressure on the shell's surface equal to 0.1N/mm2, shell's material of a Poisson's ratio of .3 and Young's modulus of 68.95N/mm2 with shell boundaries all hinged and the shells are thick. If the "Degenerate solid" or "Reissner-Mindlin" formulations were used to analyze the deflection caused by a concentrated load on a shell, only the total deflection can be calculated, not the finite deflection. The main interest of the study was to give at least one example of how a fully curved structure maybe modeled as a surface having only one curvature "spherical or a rotational parabola", however this theory failed because there were small inequalities when the models where compared regarding the central deflections, and these inequalities were unacceptable. Finally, two spherical models where tested and distinguished, and the thesis of Ma was examined, which confirmed that the precautions that were made for testing spherical shells in this study were valid, and obtained the conclusion that the current studies is facing a problem in deciding the proper dimensions of the structures models.

(Crosheck, 2001) This lecture speaks about the importance of employing computerized FEA, technology and techniques in the automotive industry. It presents examples of how the results obtained by FEA software were compatible with these collected from expensive, time consuming experiments. The lecture also presents a model of a structural design iteration process that is cost effective and can provide a huge amount of useful data. The final conclusions were that Full Vehicle Structural Durability Behavior is predictable, fast enough to be practical, cost effective and can be optimized by the use of computer FEA packages before manufacturing.

(Duni, 2003) Throughout this paper, a description of a numerical method is used to obtain a solution for the dynamic simulation for all the details involved with a vehicle on the road facing all kinds of obstacles, it depends on the finite element analysis method. The validity of FE models for tires is investigated and discussed. A strategy to combine between the static and dynamic simulations has been chosen; this simulation used the "Abaqus" implicit and explicit codes, which turned out to demonstrate the dynamic on various kinds of obstacles was successful. This study was conducted Fiat Punto. The paper gave many conclusions obtained by the research, the simulation process employed (the one using Abaqus codes) provided an accurate prediction of dynamic response for all vehicle parts; showing the loads affecting on the structure exactly as in reality, as well as the consequent damage produced by them. The most important result that the study presented was the establishing a limited degrees of freedom FE model for the tires which didn't need repetitive calibrations and comparisons needed by the multi body tires models, minimizing efforts costs and time. Sensibility tests have been performed for various types of analysis. The power of Abaqus codes as a tool to provide required static, quasi-static and dynamic simulations was showed; its strength arises from the fact that if a particular problem couldn't be solved by the implicit code, it can be transmitted to the explicit code and vice versa. Finally, the study clearly showed that this kind of approach can be successfully employed in the automotive industry to provide the required pre-testing simulations and evaluations of the car parts especially for the stresses caused by road obstacles or dynamic movements.

(Maasdam, 1999) This lecture presents the aspects involved in vehicle library analysis, conducted at DAF trucks, in order to obtain static and dynamic analysis from a vehicle model. There are two main reasons that make commercial vehicles FEA a time consuming and high cost operation: variation in vehicle's requirements and specification depending on the client's request, and the usual need for a full real vehicle model for the purposes of obtaining dynamic and static behavior data in order to simulate it, and thus, a huge number of data to be analyzed (usually, vehicle model contains 600.000 degrees of freedom). Another obstacle that face the designers is that the ride-comfort condition requires that the frequency be between 0-20Hz which make heavy components connected to chassis (such as fuel tanks) produce a non symmetric dynamic load and causing also the whole structure to be not symmetric, not forgetting to mention that these objects themselves are subjected to static a fatigue analysis. The paper gives an example of how "frequency response functions" are calculated with a program called MSC/NASTRAN, and then processed further more using a special tool box in order to estimate the comfort of the passenger and loads resulted from different driving and road conditions. The summary of this lecture presented at the MSC Worldwide Automotive Conference was presenting an approach to create an assembly for outer parts, a model of saving conducted tests in a library in order to be reused when needed, enhancing the assembly operation, the post processing is improved because there is no need to go through the processing of the inner structures all over again, which made the design and simulation processes more flexible, efficient and time saving.

6- References

- Al-Asady, Nawar, Abdullah, S., Ariffin, A., Department of Mechanical and Materials Engineering at UKM, Selangor, Malaysia, (2009), Comparison Between Experimental Road Data and Finite Element Analysis Data for the Automotive Lower Suspension Arm, European Journal of Scientific Research.

- Atiqullah, Mir, 2009, Fundamentals of Finite Element Analysis, Strength of Materials Lab, Southern Polytechnic, Georgia's Technology University, available at:http://www.spsu.edu/met/matiqull/Strength%20Lab/FEA-Lab1%20Lecture%20slides.pdf.

- Cirak, Fehmi, Scott, Michael, Antonsson, Erik, Ortiz, Michael, Schr¨oder, Peter, 2001, Integrated Modeling, Finite-Element Analysis, and Engineering Design for Thin-Shell Structures using Subdivision, Division of Engineering and Applied Science, California Institute of Technology, Pasadena, U.S.A.

- Crosheck, James, 2003, The Integration Of Analysis And Test For Full Vehicle Structural Durability, a lecture at NDIA SBA Conference.

- DraškoviÄ‡,1Zoran, BerkoviÄ‡, Mladen, 1999, Military Technical Institute, KataniÄ‡eva and Faculty of Mathematics at the University of Belgrade, Belgrade, Yugoslavia.

- Duni E., Monfrino G., Saponaro R., Caudano M., Urbinati F., FIAT Research Center, and S. Marco, P. Antonino, FIAT Auto Spa, 2003, NUMERICAL SIMULATION OF FULL VEHICLE DYNAMIC BEHAVIOUR BASED ON THE INTERACTION BETWEEN ABAQUS/STANDARD AND EXPLICIT CODES, Fiat Corporation, Torino, Italy.

- Maasdam Ir. J., 1999, A FINITE ELEMENT VEHICLE ANALYSIS LIBRARY FOR COMMERCIAL VEHICLES, a lecture at the MSC Worldwide Automotive Conference, DAF Trucks N.V., Eindhoven, The Netherlands.

- Smith, Brock, Wible, Ryan, 2003, Finite Element Modeling and Analysis of NASCAR Frame, Multidisciplinary Undergraduate Research Institute, Michigan, USA, available at: http://www.engr.iupui.edu/me/courses/nascar_analysis_sp03.pdf.

- Zamanzadeh M., Larkin E., Gibbon D., 2004, A Re-Examination of Failure Analysis and Root Cause Determination, Matco Associates, Pittsburgh, Pennsylvania, USA.

- http://www.nenastran.com/newnoran/solver

Appendix A: Initial Report

1- Introduction

SUV cars have now a significant role in transportation of passengers and goods. The body of such vehicles exposes for different kinds of loads which need to be analyzed and discussed. Finite Element Analysis can be considered one of the main pillars that the new industrial strategies is standing on, and of course the automotive industry can be considered one of the most interested industries in the field of finite element analysis. Every day all automotive factories do a numerous number of trials on the newly developed car parts from all categories and the finite element analysis takes the highest number of these trials. It is hoped in this project to cover and study SUV body, which can be considered one of the initial cases of study and may play a key role in the safety of the passengers and goods, so it should be given a fair share of the study and the analysis of the car body design. Solid Works can be considered one of the most reliable software in the field of FEA, in which most of the cases that an engineer may face during his career or study can be modeled and simulated in this software with a very accurate results. According to this, SolidWorks can be considered one of the best choices for this project. In this project solid work will be used to analyze the loads on such bodies of the SUV automobiles.

FEA one of the important issues to be reviewed and discussed in this project as a numerical method used to approximate the solution of most complicated engineering problems, in spite of long time taken and hard manual calculations required to solve a simple non- homogeneous problem. Due to the development of computation systems this method used nowadays as a programming base of most engineering software packages ((Kenneth H. Huebner, et.al, 2001)).

2. Project aims and objectives

2.1 project aims

The aim of this project is to make a basic finite element analysis for a previously specified SUV car body, at which the body of the car is going to be under many loads and forces affecting various parts from it, so it can finally approach a fully defined body that should face some modifications to bring a step forward toward engineering perfection.

2.2 Project objectives

1. 1- Make a stress, strain and deflection analysis to a pre-designed SUV body frame, Chassis or parts using SolidWorks Finite Element Analysis software.

2. 2- Modify the tested object(s) selected in part one by re-designing it in a way that will allow it to overcome its limitation by adding parts, removing parts, increase or decrease the overall size, change the material in use, changing dimensions or by any other necessary change.

3. 3- Test the result(s) obtained by step 2 in order to confirm the validity of the modified design, and, to be more specific, make sure that mesh size and properties are functional and applicable.

4. Put the reliability of SolidWorks under test and compare the results that been obtained for a selected part with other finite element analysis software's.

3 Project resources

In this project data has been collected from:

1- Journals

- Crosheck, James, 2003, The Integration Of Analysis And Test For Full Vehicle Structural Durability, a lecture at NDIA SBA Conference.

- DraškoviÄ‡,1Zoran, BerkoviÄ‡, Mladen, 1999, Military Technical Institute, KataniÄ‡eva and Faculty of Mathematics at the University of Belgrade, Belgrade, Yugoslavia.

- Maasdam Ir. J., 1999, A FINITE ELEMENT VEHICLE ANALYSIS LIBRARY FOR COMMERCIAL VEHICLES, a lecture at the MSC Worldwide Automotive Conference, DAF Trucks N.V., Eindhoven, The Netherlands.

- Zamanzadeh M., Larkin E., Gibbon D., 2004, A Re-Examination of Failure Analysis and Root Cause Determination, Matco Associates, Pittsburgh, Pennsylvania, USA.

- http://www.nenastran.com/newnoran/solver

2- Books

· . Logan , 2009, A First Course in the Finite Element Analysis is a very excellent and simple language text book, which can explains the basic foundation of the finite element analysis and its application in the field of mechanical engineering

· Beer and Johnston,2006, Mechanics of Material, this reference will provide very strong background in the Mechanics of Materials is needed to successfully accomplish this project. All stresses, strains, deflection and other important topics in the field of mechanics of material.

3- Equipments and software

* SolidWorks Software will be used as the main FEA software package in this project to design ,simulate and analyze the SUV car body.

* SolidWorks training manuals presented by SolidWorks can be considered the best way to understand in deep details all the required skills needed to reach the final satisfying results of this project.

Name: Abd-Elatif Malallah graduation project SUV Car Simulation

4- Methodology

In this work numerical method using solid work software will be used to design and analyze the loads affected on the body of the SUV car. Last studies ignoring the use of solid work in such analysis. Solid work is powerful software that gives an exact solution which is closes to the real case. Also the reliability of SolidWorks is high and it may also to do some kind of comparing between results for the same sample model using deferent 3D CAD software or last experimental studies. This means that the general approach will undertaken to achieve this project will be practical work by design where analytical calculations will take place then will be simulated using FEA software package to be analyzed. The Reliability of SolidWorks and its ability to give approximate results supporting this methodology reliability and validity.

4.1 Analysis

Analysis as been told before is going to be done using SolidWorks Simulation that can provide with a various types of analysis that can be used in the project. Stress, strain, deformation and factor of safety can be found for analyzed models using SolidWorks.

4.2 Conclusion

One of the most advantages of this project is the capability of doing needed analysis using SolidWorks, which provided a very handy tool for analysis. But the most critical disadvantage in this project is the lack of resources that is talking about this subject. Se a very good effort should be considered in this project to reach trustable results.

5- Project Management

5.1 project risks Analysis:

it is extremely difficult to design SUV body with the given period of time for this project so it may be supplied with a SolidWorks Model of the chosen SUV body because which may distort the research from the main objectives of this study. To manage this risk some visits to a research centers that do similar researches repeatedly would be very helpful to meet the real world analysis procedures and to compare it later with the way that we have followed all along this project to achieve our last results for this interesting project.

5.2 Project Gantt chart: the following Gantt chart details all activates, works and millstones required to close this project on high quality standards and on time.

Name: Abd-Elatif Malallah graduation project SUV Car Simulation

6- References / Bibliography

* Logan ,2009, "A First Course in the Finite Element Analysis", Fourth edition, Thompson.

* Beer and Johnston, 2006, " Mechanics of Material, fourth edition in SI units", McGraw Hill.

* SolidWorks 2009/2010 training manuals by SolidWorks

* Hayata Uwai, Shinkichi Toyosaki, Koichi Sagawa, And Nobuhiko Takahashi, 2006, "A Study On Ahof400 Which Is Possible Car To Suv Compatibility Evaluation Method", Nissan Motor Co., Ltd. Japan, Paper Number 07-0391.

* (Kenneth H. Huebner et.al 2001 ), Kenneth H. Huebner ,Donald L. Dewhirst, Douglas E. Smith, Ted G. Byromv, 2001, The finite element method for engineers, Wiley-IEEE.

SUV car body with finite element analysis simulation

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