Project Scope
The purpose of this project is to demonstrate the capability of designing and
performing calculations, FEM and computer simulations on a mechanical component
(car piston) using commercial software. The project scope will be to investigate an
engine piston for a Toyota. The first part will involve doing the geometry of the engine
position i.e. using the measurements of a real Toyota piston. Only one piston will be
investigated. Hypermesh or Ansys software will be used for the engine piston’s
geometry and the Finite Element Modelling.
The piston will be calculated with the use of Finite Element Modelling and Computer
simulations. The desired outcomes are having a piston model and FEA results for
modal, thermal, fatigue analysis, closed form solution (bending and torsion) and a
detailed discussions on the results will be discussed in detail in the project.
Introduction:
In the recent years, industries, especially in field of mechanical design, there has been
extensive research, development and optimization technology invented for easy use, reliable
application, cost saving, time management and product aesthetic appearance. Software tools
for Finite Element Analysis (FEA) and Finite Element Modelling (FEM) and very helpful for
designers, production purposes, as well as for researching novel techniques and products.
There are many engineering applications which are solved by software tools.
Generally mechanical components are design and finalized by three different techniques. If
two techniques are satisfied within a given condition and require application, then the design
is finalized for production.
Before the production, the first design of piston or any mechanical component are prepared in
an analytical solution. The analytical solution is solved with the design fundamental and
formula of standards geometry and parts. The result of analytical solution get further software
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tool is use for analysis purpose and finalizes the design of particular component which give
result of analytical solution. For software analysis generally Ansys and Hypermesh software
tools are used for analysis and optimization and finalize the product design. The Ansys work
batch tool can give same environment which have to work in practical condition. Ansys tool
can give result before the failure occurs or can estimate require mechanical input and
desirable output. For optimization Hypermesh is generally use for different optimization
technique use and different parameter can get by using Hypermesh designing software.
Keywords: Piston design, FE analysis, Hypermesh, Optimization.
Finite element analysis: it is numerical method and multi physics technique which is useful
for solve engineering problem. In FEA simulation process first create mathematical model of
product with boundary condition and loading condition. After that it divide in to domain to
sub domain is called element. Element have different size and different geometry with node.
In specific model elements are connect with node and all elements connect with the nodes
and create complete model with finite element size. (Al-Momani,2008)The meaning of finite
element method is to divide entire volume of product into define size of element. The entire
geometry divide into small size of element and elements are connecting with nodes. With
applying loading of particular product, stress induces with consideration of each and every
element of product. The result shows the maximum stress induce at particular region and
minimum stress at particular region. Forms that result are useful for design optimization and
design modification. Finite element analysis can perform by analytical approach as well but it
is difficult for complex geometry analysis with analytical approach of FEA. For complex
geometry it is good for use software tool like Ansys, Hypermesh, ABAQUS, and Nastran etc.
Piston is a heart of I C engine which is important for design as well as working purpose in I C
engine. The function of piston is to concert heat energy into pressure energy and kinetic
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energy for the combustion and for mechanical works. The designing of piston is most
complex and tough among the other component of I C engine because need for piston design
is that it should be optimum weight, sufficient to carry high thrust and impact load, strong
enough for all directional load, optimum cost. For the all require properties of piston there are
necessary to analysis by the software tool Ansys work batch or Ansys APDL. There are
various analysis tool available Ansys work batch module like static structural analysis,
thermal analysis, vibration analysis, transient analysis, fatigue analysis, optimization
technique like design of experiment method, sensitive analysis. For the piston analysis and
design for finding stress distribution, deformation, life cycle etc. there are need part model
which create in Computer aided designing tool cro-o parametric or solid works software
which easy to create part like piston. After that piston part import into Ansys work batch tool
for analysis purpose. it also easy to create part file in Ansys work batch tool but rather than
create part into Ansys it is easy to create in modelling software like solid works, cre-o
parametric.
ANSYS work batch is the platform where industrial engineer use software for deep suit of
engineering simulation technology built. (Kongari, 2015) This is an advance technology project
schematic version which builds bridge between advance simulation and existing design
approach. By using Ansys workbench tool it guide for metaphysics analysis for complex part
and simulation which is not easy task for analytical design in Ansys. There is connectivity
with CAD modelling tool by creating bridge between modelling and analysis in software.
There are great technique with auto mashing which give define element size of part for
accurate and desirable result.
The produce for FEA analysis in Ansys work batch tool:
Create geometry in solid modelling software like solid edge or solid works etc.
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There is availability to build bridge between solid model and Ansys work batch
analysis.
Import geometry form CAD model into Ansys work batch.
Assign specific material properties to model in Ansys geometry modular. Generally
cast iron use in production of piston.
Apply mashing to part model in designer module file. The function of mashing is to
divide whole component into finite part. Therefore assign appropriate mashing to part
model. There are various options available in Ansys file to assign mash properties like
tri element, tetra element, and quad, hex element etc. And another purpose of
mashing is for accurate result after simulation and analysis.
Assign boundary condition and loading condition to part model. In this case static
analysis, thermal analysis, dynamic analysis and vibration analysis should perform to
design output and complete design.
Find the result form designer module of Ansys example like In static analysis deformation
and stress is a considerable factor for design outcome. For thermal analysis t need maximum
temperature induce at the top surface and outer surface of piston, for vibration analysis it
should be nature frequency of piston at extreme position considering the working condition
of piston in I C engine. For fatigue analysis it should get result of life span of piston after the
approximate year of working. (Montazersadgh, 2007)
Mashing of piston for analysis and optimization:
Generally mashing is done in FEA for close and accurate result. The purpose of mashing in
FE analysis is for create arbitrarily volume element with divide part modal equal size in
define elements size.
Static structure analysis of piston by using Ansys work batch:
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It is easy to perform analysis by CAD interface and FE analysis. First import model
form CAD model to Ansys work batch.
Assign aluminium alloy material specification to model.
Generate model in geometry interface in Ansys work batch.
Assign mashing with specific element size. Mashing create for divide element into
specific size for entire volume of model. The advantage of mashing is that we can
identify sacrifice region where most of effect are generate and modified according to
safe design consideration.
Applying loading condition and boundary condition for piston. For static structural
analysis the boundary condition is a volume of cylinder where piston travel and the
travelling path where piston travel top dead centre to bottom dead centre.
Loading condition defined by the how much amount of outcome require form I C
engine and life span of piston and cylinder. Also depends on the input applied for
moving reciprocating of piston.
Find the result of deformation and stresses of piston design. Deformation
consideration form friction losses, stresses are generating due to wear and tear of
piston due to reciprocating motion of piston. Stress is von –miss is stress, normal
stresses and axial thrust stresses. (Norberg et.all.,201)
Finally compare result with analytical approach.
All kind of analysis cannot perform with analytical approach and cannot perform before the
finalize product in terms of practical approach. For this reason Finite element analysis is
useful for design, development and optimization purpose.
Thermal and geometric properties:
For prepare product design of piston it is important to consideration of thermal stress
distribution over the top surface of piston head. Therefore it should be thermal analysis for
obtain intensity of head which produce during combustion in I C engine. The deformation
and stress produce over the surface of piston head should be within acceptable limits. Form
the result of temperature distribution over the piston which give conclusion that how much
amount of heat generate and how much amount of temperature can sustain by piston before
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manufacturing. Another reason for thermal analysis using Finite analysis in Ansys work
batch is that mainly during working condition the chance of failure of piston ring is more due
to wear and tear over the surface of cylinder. For that lubrication film fills between the
surface of piston and cylinder. During analysis first identify material selection for particular
design product. Here, for prepare model or prototype of piston it should be good for using
aluminium alloy because aluminium have great amount of thermal expansion co efferent
which is more the cylinder bore. Therefore it can operate at high temperature for infinite life
consideration. In practical thermal analysis is a difficult task to identify the temperature and
deformation due to heat over the surface of piston. So form the Finite element analysis we
can conclude that we can find certain temperature and heating capacity sustain by piston from
the result of Finite element analysis.
Optimization of Product design:
Optimization is a technique which give result at optimum condition with design constrain. In
design of piston the mass of piston, area cover due to heat over the surface of piston, piston
ring thickness, width can optimize with constrain and boundary condition. (Sonar,2015)
The final product design and analysis in finite element analysis the product have to optimize
at certain level. The purpose of optimization is to reduce the mass of material and resize the
product at optimum condition. From the result which get form ansys work batch module with
require analysis perform we get constrain and loading condition for optimization. Hear we set
minimization technique for optimize the mass of piston. The result of von –miss is stress and
factor of safety which get from ansys are constrained of optimization tool. The objective
function of the piston design is to reduce mass. Form Hypermesh tool software use. Provide
medium for CAD system and Finite element analysis.
The advantage of Hypermesh is to obtain any optimization which is not possible in Ansys or
other software. Example like topology optimization, topography optimization, size
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optimization, shape optimization, etc. for product design like piston our objective function is
to reduce mass or optimize mass with stress and factor of safety constrain. The fundamental
work of Hypermesh tool reduces or maximizes the particular term up to 80 % of refinement
of product. Procedure of optimization in Hypermesh as following:
Import CAD model into Hypermesh software
First create folder of material properties of piston.
Mash component and assign properties.
Define constrain.
Applied loading condition by load collector.
Define specified output by cart image
Define load step.
Define output like size optimization, shape optimization,