April 23 th , 2013 Sangwoo, Cha Shape Optimization of Engine Moving Components with Hyper-Study Integration Hyundai·Kia Motors R&D Center Session1: Optimization
Jul 06, 2015
April 23th, 2013
Sangwoo, Cha
Shape Optimization of Engine Moving Components
with Hyper-Study Integration
Hyundai·Kia Motors R&D Center
Session1: Optimization
Contents
Introduction
- Overview: engine moving components
Shape Optimization of connecting rod
- Analysis Procedure
- Approach for weight reduction
- Optimization results and shape
Shape Optimization of engine piston
- Analysis Procedure
- Approach for weight reduction
- Optimization results and shape
Conclusion
- Summary and conclusions
Overview: engine moving components
Engine moving system
- composed of Piston, Connecting rod, Crankshaft
Role of piston and connecting rod
- transferring force from expanding gas by firing to the crankshaft for making engine power
Increasing needs for Optimization
- CO2 emissions and cost down by weight reduction
- frequently, failure occurrence by the hard condition according to the trend of high power
Connecting rod failure Piston failure
Connecting rod Piston
Crankshaft
Introduction
Contents
Introduction
- Overview: engine moving components
Shape Optimization of connecting rod
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Shape Optimization of engine piston
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Conclusion
- Summary and conclusions
Analysis Procedure Connecting rod
FE model construction
Optimization definition
Structural analysis
Evaluation: postprocessing
Optimization analyze/result
Optimization(Iteration)
Sensitivity through DOE
Re-Optimization
Optimization results and shape
Sensitivity
Optimized shape design
Suggestion of design parameter
Optimization shape design
Fatigue
Safety Factor Deformation Buckling
Safety Factor
Simulation: 4 load case (batch job)
Hypermesh
Design variable: morphing
Hyperstudy
Objective function and
restraint definition
FEMFAT In-house S/W In-house S/W
Assembly Tension/
Compression Buckling
*ABAQUS
Evaluation item for durability Connecting rod
Indirect
evaluation of
bearing wear
Buckling
prediction
Fatigue Safety Factor Big end Stiffness Buckling Safety Factor Item
Problem
/
Analysis
result
Evaluation
What: fatigue safety factor
How: ratio of multi-axial stress
amplitude and fatigue strength
S/W: FEMFAT
Fatigue failure
prediction
What: Big end deformation
How: calculation at tension
loading by least square method
S/W: In-house program
What: Buckling due to high
combustion force
How: Merchant-Rankine formula
(considering eigenvalue, plastic)
S/W: In-house program
Criterion Sorry, it’s confidential
Connecting rod Optimization approach
Optimization objective
- Minimize current connecting rod weight
Response and Constraint
- Fatigue safety factor
- Big end stiffness
- Buckling safety factor
Shape restraint
- No interference with piston and cylinder
block at the dynamic motion
- Limit of the manufacturing tool
(ex. Curvature and angle of cutting tool)
- No big change of the metallic pattern
Criterion
satisfaction
Piston pin
Crankshaft
Connecting
rod
Cap
Rod
Design variables: morphing shape Connecting rod
Small end diameter Small end thickness Shank width(outer)
Shank width(inner) Shank thickness1 Shank thickness2
*Outer *Inner
(section)
HyperMorph
- definition of domain, handle
- based on the design history(PROE)
Design variables
- total 6 shape variables
Upper, lower bound
- using sensitivity analysis(DOE)
Domain, handle
Small end
shank
Big end
Connecting rod Optimization results
Objective Weight 9%,
Constraint
Fatigue Safety Factor
Big end stiffness
Buckling Safety Factor
Response Result
11%,
Same
7%,
Design variable history
Fatigue Safety Factor
But, Criterion satisfaction
Bad
Good
Current Optimization
Optimization shape Connecting rod
Optimization process Measuring dimension(optimization shape)
CAD design(at the design team)
: Current
: Change
: Optimization
Contents
Introduction
- Overview: engine moving components
Shape Optimization of connecting rod
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Shape Optimization of engine piston
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Conclusion
- Summary and conclusions
Analysis Procedure Piston
Structural analysis
Optimization(Automation and Iteration)
Stress analysis: ABAQUS s/w
Evaluation: postprocessing
Fatigue Safety Factor: FEMFAT s/w
Mass center Extract (from ABAQUS *.dat)
ABAQUS keyword:
Mass center of
element set
Reading safety factor
from FEMFAT result Load and boundary condition
Stress distribution FE model
* temperature * profile: skirt,
pin hole
* Firing pressure,
side force, inertia
Optimization approach Piston
Optimization objective
- Minimize current piston weight
Response and Constraint
- Fatigue safety factor: Criterion satisfaction
- Piston mass center: +/- 5% change bound
(no great difference in the dynamic characteristics)
Shape restraint
- No change of piston crown thickness
(no great difference in the piston temperature)
- Limit of the thickness for casting process
* After optimization for weight reduction, dynamic
analysis is needed for dynamic characteristics Dynamic analysis(using PISDYN)
Crown thickness
Mass center
Piston Design variables: morphing shape
RH thickness
Under-crown area Bottom height
Thrust thickness
LH thickness Oil drain height Oil drain thickness
A-thrust thickness Thrust skirt angle A-thrust skirt angle
Domain, handle
Piston Optimization results
Objective Weight 11%,
Constraint
Fatigue Safety Factor
Piston mass center
Response Result
10%,
Same But, Criterion satisfaction
Objective(weight) history
Optimization weight
Bad
Good
Fatigue Safety Factor
Current
Optimization
Piston Optimization shape
Measuring dimension(optimization shape)
CAD design(at the design team)
: Current : Change : Optimization
Optimization process
Contents
Introduction
- Overview: engine moving components
Shape Optimization of connecting rod
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Shape Optimization of engine piston
- Analysis Procedure
- Approach for weight reduction
- Result and Optimized shape
Conclusion
- Summary and conclusions
Conclusions
Using the shape optimization techniques with Hyper-Study,
1) for the connecting rod, a mass reduction of 9% was achieved.
2) for the piston, a mass reduction of 11% was achieved.
satisfying the restraint and manufacturing restriction
Defining the design variables based on the PRO/E model history,
the optimized shape was easily transferred to the CAD design.
HMC has applied the optimization techniques using Optistruct,
Hyper-study for weight reduction or durability increase of the
other engine components.
Summary and Conclusions
On going study..
Crankshaft optimization
: Current
: Optimization
* Substructuring method for solving
Thank you for your attention !!