Cab Door Latch Opening effort reduction using Altair MV & MS
Tata Motors Ltd
Shailesh Patil
Kiran Karale
Fyaz Farook
Date – 11th June, 2014
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Company Profile
•
Tata Motors Limited is India's largest Automobile Company established in 1945.
•
Consolidated revenues of INR 2,32,834 crores in 2013-14.
•
Leader in commercial vehicles in each segment, and among the top in passenger
vehicles.
•
World's fourth largest Truck and Bus manufacturer.
•
Tata Motors is committed to improving the quality of life of communities by working
on four thrust areas - employability, education, health and environment.
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• Objective
• Cab door latch opening effort reduction.
• Statement Of Problem
• To design a Cab door latch with minimum opening effort.
• Scope
• Cab door latches of TML passenger and commercial vehicle.
• Continuous design quality improvement & cost reduction programs for all
variants.
• Lead time reduction for new vehicle programs with early CAE feedback
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Latch Load Transfer Path
LINK4(Cam)
LINK3(Pivot)
LINK2(Lever)
LINK1(Push button)
Final Dislodgement of Door Happens
In Striker Link
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Cab Door Latch Details
Tension
Spring
Latch
Base
Cam
Link
Compression
Spring
Pivot
Link
Surface to Surface
Rigid Contacts
Lever
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Parameters Affecting Latch Opening Effort
(A) Door Handle
•
Push Button Spring stiffness
(B) Latch Mechanism
•
Compression Spring Stiffness, free length
•
Tension Spring Stiffness, free length
•
Lever - Pivot point to Load application point distance
•
Cam link profile
•
Pivot link profile
(C) Door Assembly
•
Primary & Secondary seal stiffness
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Design Proposals
Design2
Design1
Lever Length Modification
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Design3
Cam Link Modification
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Latch MBD Model
Total bodies : 4
Type of Contact Modeled: Impact
Analysis Type: Transient
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Process Methodology
Latch Assembly CAD
Data
Run Transient
Analysis
Latch Assembly
Hypermesh (.hm file)
Plot Outputs in
Hypergraph
Import .hm file to MV
Measure Latch
opening effort
MBD model with latch
graphics in .h3d format
Define joints, contacts
motion , Markers &
required outputs
Identify Design variable
(spring properties, Link
shapes)
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No
Effort <
Target
Yes
Prototype
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Latch MBD Model Simulation
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Effort Required For Latch Opening
Effort
Max. Value
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DOE Using Hyperstudy
• Design Variables




Tension spring stiffness
Tension spring free length
Compression spring stiffness
Compression spring free length
• Design Responses
 Force on lever
• DOE Class
 Full Factorial
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Response
DOE Results
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DOE Results
Tension
Spring
Stiffness
Compression
Spring
Stiffness
7x
Response
7x
6x
5x
3x
2x
Initial Design
Final Design
Desirable latch
opening effort band
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Summary
Benefits
•
CAE pre-processing, solution & post processing time reduction.
•
MBD DOE/Optimization helped to finalize design variables.
Limitations/Challenges
•
Contact with flexbody not possible.
•
Tuning of contact parameters
Future Goals
•
Door assembly and Door seal stiffness effect to be captured
•
Multi model DOE/Optimization
•
Capturing flex body effect
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Thank you
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