2. 2
Table of Contents
1. Project objective: ........................................................................................................................................................... 4
2. Methodology.................................................................................................................................................................. 4
3. Description of Steps....................................................................................................................................................... 4
3.1.Geometry:................................................................................................................................................................ 4
3.2 Material.................................................................................................................................................................... 7
3.3 Boundary Conditions................................................................................................................................................ 7
3.4 Meshing.................................................................................................................................................................. 8
4. Results............................................................................................................................................................................ 9
4.1 Normal stress along Y axis........................................................................................................................................ 9
4.1.1 Valve without chamfer or fillet ......................................................................................................................... 9
4.1.2Valve with chamfer..........................................................................................................................................10
4.1.3 Valve with fillet of radius 7.8486mm..............................................................................................................11
4.2 Normal stress along X axis .....................................................................................................................................12
4.2.1 Valve without chamfer or fillet .......................................................................................................................12
4.2.2 Valve with chamfer .........................................................................................................................................13
4.2.3 Valve with fillet of radius 7.8486mm..............................................................................................................14
4.3 Normal stress along z axis......................................................................................................................................15
4.3.1 Valve without chamfer or fillet .......................................................................................................................15
4.3.2 Valve with chamfer .............................................................................................................................................16
4.3.3 Valve with fillet of radius 7.8486mm..............................................................................................................17
4.4 Equivalent Stress....................................................................................................................................................18
4.4.1 Valve without chamfer or fillet .......................................................................................................................18
4.4.2 Valve with chamfer .........................................................................................................................................19
4.4.3 Valve with fillet of radius 7.8486mm..............................................................................................................20
4.5 Shear Stress............................................................................................................................................................21
4.5.1 Valve without chamfer or fillet .......................................................................................................................21
4.5.2 Valve with chamfer .........................................................................................................................................22
3. 3
4.5.3 Valve with fillet of radius 7.8486mm..............................................................................................................23
4.6 Total Deformation..................................................................................................................................................24
4.6.1 Valve without chamfer or fillet...........................................................................................................................24
4.6.2 Valve with chamfer .........................................................................................................................................25
4.6.3 Valve with fillet of radius 7.8486mm..............................................................................................................26
5.Overall Results ..........................................................................................................................................................27
5.1 Tabular ...................................................................................................................................................................27
5.2 Graphs....................................................................................................................................................................28
5.2.1 Variation of maximum stress values with radius of fillet................................................................................28
5.2.2 Variation of total deformation with radius of fillet ........................................................................................28
6. Model Limitations ....................................................................................................................................................29
7. Conclusions ..................................................................................................................................................................29
4. 4
1. Project objective:
a) Model different variations of the engine valve using Catia for the following cases:
b) carry out static analysis on the different variations of engine valves
c) compare the results in the different case studies and plot a variation graph
2. Methodology
a) Modeling in catia. It is then converted to igs file and imported into workbench
b) Material property of High Grade Alloy Steel ( 42CrMo4 ) is input
c) The structure is meshed
d) Solving the problem after giving appropriate loads and boundary conditions.
e) Obtaining the result
f) Processing the results to plot graphs and observe trends
g) Provide conclusions on the results
3. Description of Steps
3.1.Geometry:
The following standard dimensions given were used to model the geometery using CatiaV5R21
Here Given A = 31.75
B = 111.91
C = 7.8486
D = 45 deg
5. 5
One of the things to be noted here is that the dimensions of the height of the base is not given. So
we will not be able to model the geometry accurately. We will assume the height of the geometry
for modeling purpose.
The following different variation of the engine valve was considered according to following case studies
i) with a chamfer of 45deg and edge 8mm
ii) Without any fillet or
chamfer
6. 6
iii) With a fillet of 7.8486 mm ( a valve typically has a fillet radius equal to its stock
diameter)
iv) With a fillet of 1mm
v) With a fillet of 2mm
vi) With a fillet of 3mm
vii) With a fillet of 4mm
viii) With a fillet of 5mm
ix) With a fillet of 6mm
x) With a fillet of 7mm
7. 7
3.2 Material
High Grade Alloy Steel (42CrMO4) material is used for the purpose. It is known for its excellent
wear resistance and low coefficient of friction. It is primarily used in high stressed valves.
PROPERTIES High Grade Alloy Steel
YOUNG’S MODULUS 210 GPa
POISSONS RATIO 0.32
YIELD STRENGTH 800 MPa
DENSITY 7830 Kg/mm^3
3.3 Boundary Conditions
For the purpose of computational efficiency the problem is considered as a static structural
problem instead of a dynamic problem. It is also done as static structural since we are
interested in the effects of fillets of different radius, no fillet condition and chamfer on the
engine valve only. So as per requirement of our simulation the following two boundary
conditions are used:
i) A force of 900N applied on the upper surface. This is approximately the pre tension force exerted
on the valve when the spring having spring rate of 300lbs/in is compressed by 0.703in
ii) The colored region below known as valve seating is assumed to be a fixed support.
8. 8
3.4 Meshing
Mesh Method was set to tetrahedron method and a relevance of 100 is used. The Meshing sizing property
was also set to fine. A refinement is provided at the fillets as these are regionsof primary importance in our study
of stresses. We find the number of nodes is 94214 and number of elements is 64117. The maximum skewness is
0.57 which is below 0.9 and therefore conforms to a good quality mesh criteria.
28. 28
5.2 Graphs
5.2.1 Variation of maximum stress values with radius of fillet
5.2.2 Variation of total deformation with radius of fillet
29. 29
6. Model Limitations
a) Model only simulates static loading that is conditions when engine is not running.
b) Impact load that occurs when the engine runs at high speed has not been considered.
c) This analysis should be used only to study the effects of absence of fillet, different fillet radius, and
chamfer on an engine valve. Other analysis considering the impact effect, thermal effect etc has to be
considered before the valve is put to real world use.
7. Conclusions
a) As noted earlier since we are not provided with the height of the base we will not be able to
validate the paper to a high level of accuracy.
b) Chamfering reduces normal stress along x and z direction significantly but normal stresses along
y directions are not affected greatly.
c) Filleting the notch greatly reduces the stress concentration and distributes the stress concentration
along other directions as well. This ensure the peak stress is distributed equally around. This
reduces chances of crack initiation due to concentration.
d) Maximum stress reduces with increase in fillet radius. The value of stress is inversely
proportional to the radius of fillet.
e) Compared to standard dimensions of fillets and chamfer given, fillets have the ability to reduce
maximum stress concentration compared to chafers
