2018 ncode user group meeting –north america | february 28

HBM Prenscia: Public

© 2018 HBM

2018 nCode User Group Meeting – North America | February 28 – March 1


© 2018 HBM

Identification and Analysis of Critical Time Slices

Based on Damage Time History

Ken Citrin


© 2018 HBM

3

• Mahindra Automotive North America (MANA) was founded in 2013• Headquarters of Mahindra Group’s Automotive operations in North America

• 300+ automotive professionals

• $230 million invested in Southeast MI

• The first new automotive OEM to set up manufacturing in Southeast Michigan in 25‐years

• Facilities in Auburn Hills, Pontiac and Troy• MANA spans 400,000 ft2 across Metro Detroit

• Operations are ramping up• Forthcoming release of our first off‐highway vehicle

• Will add 400 jobs and invest another $600 million in the local economy by 2020

Mahindra Automotive North America

Auburn Hills

Pontiac

Troy


© 2018 HBM

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• The North American automotive industry predicts component life from acquired load time histories

• Analysis output is a scalar value • Does not provide insight into which events are the primary contributors

• Analysis of discrete time slices are used to develop countermeasures• Identifying the damaging events

• Imprecise

• Time consuming

Identify Damaging Time Slices for Component Analysis


© 2018 HBM

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• A GlyphWorks flow has been developed to aid identification of the major contributors to fatigue damage

• Events that occur infrequently with high damage

• Events that occur frequently with high cumulative damage

• A GlyphWorks flow has been developed to create the FEA data deck cards• Cards had been created manually

• Time consuming

• Error prone

• These processes have increased productivity and confidence

Using GlyphWorks for Time Slice Identification


© 2018 HBM

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Challenge Solution

Summary

Results

Identify critical time slices for component analysis

Export the time slices into the FEA

GlyphWorks processes are used to identify specific events based on damage and cycle counts

GlyphWorks extracts the loads at the selected time slice and writes bulk data deck cards for the FEA

Greater insight into component performanceIncreased efficiencyReduced errors


© 2018 HBM

7Process Overview

Hot Spot Identification

Strain/Time History

Damage/Time History

Damage Rainflow Cycle

Count

Tabulated Damage by

Cycle

Select Time Slice

Extract Load Channels

Write NASTRAN Bulk Data Deck

Cards


© 2018 HBM

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• Conduct component life analysis• Current methods

• Stress/Life

• Strain/Life

• Seam Weld

• Spot Weld

• Identify critical locations• Select one element at each location

• Reduces amount of data to process

Identify Critical Areas


Strain/Time History

Damage/Time History


Count

Tabulated Damage by CycleSelect Time SliceExtract Load

Channels


Cards


© 2018 HBM

9Identify Critical Locations

Identify Hot Spots Select 1 Element per Hot Spot

Perform Component Life Analysis


© 2018 HBM

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• Desired information is damage/time history• Not Available in Design Life modules

• Future Enhancement?

• Is available from GlyphWorks modules

• Output the strain/time history• These are elastic strains

• Add output pipe to Design Life analysis glyph

• Connect to a time series output glyph

• Rerun component life analysis• Selected elements only

Recover Nodal Strain/Time History


Strain/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

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• 1st of a 2‐Step Process

• Create a GlyphWorks damage calculation• Replicate Design Life analysis in GlyphWorks

• Confirm life at Hot Spots are replicated

• Output• Time correlated damage

Develop Time Correlated Damage


Stress/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

12Time Correlated Damage


© 2018 HBM

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• Damage is associated with strain cycles• ½‐Damage is assigned to cycle opening

• ½‐Damage is assigned to cycle closing

Time Correlated Damage

Damage/Time History, Location #1

Elastic Strain/Time History, Location #1


© 2018 HBM

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• Output• Damage histogram

• Strain histogram

Damage by Cycle


Stress/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

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• Associates Damage with Number of Occurrences• Highest damage due to 3 repeats

• Highest strain range causes near highest damage

Damage & Strain Histogram

Elastic Strain Histogram, Location #1

Damage Histogram, Location #1


© 2018 HBM

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• Output• Damage by cycle

• Cycle opening point

• Cycle closing point

Damage by Cycle


Stress/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

17Cycles are Ranked by Damage

Cycle Opening

Cycle Closing

Damage from Cycle

Sample Rate

50% of Damage From Only 40 Load Cycles

Two cycles have equivalent damageRepresents 2 repeats of same event

Total damage for event is doubledRanking of cycle is moved higher


© 2018 HBM

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• Identify time slices of interest• Cycles of interest

• Opening point

• Closing point

• Remove duplicate time slices• Represents repeats of an event

• By channel

• Select time slice for each critical location

• Merge slice points from all critical locations• Remove duplicate slices

Select Time Slices for Analysis


Stress/Time History

Damage/Time History


Count

Tabulated Damage by

Cycle

Select Time Slice

Extract Load Channels

Write NASTRAN Bulk Data Deck Cards

ChanNumber srate pmax pmin damage2 500 237,761 237,875 0.0004432 500 1,419,848 1,557,322 0.0003422 500 1,417,024 1,417,528 0.0003272 500 406,062 411,951 0.000322 500 409,785 406,162 0.000311


© 2018 HBM

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• 2nd Step of a 2‐step process

• Extract loads from time history• Feature list

• Simultaneous values

Extract Loads to Apply to Finite Element Model


Stress/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

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• Input• Element strain/time history

• Slice points

• FEA load/time history

• Output• Simultaneous channel values

• Each time slice

• Format is not compatible with FEA

Extract Loads for Finite Element Analysis


© 2018 HBM

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• Write NASTRAN bulk data deck cards• Eliminates manual card image creation

• nCode Support developed the SuperGlyph

• Input• FEA load/time history

• FEA load mapping

• Time slices

• Output• NASTRAN Case Control deck cards

• NASTRAN Bulk Data deck cards

Process Loads for FEA Input


Stress/Time History

Damage/Time History


Count


Channels


Cards


© 2018 HBM

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• FEA load/time history

• Time Slices

• FEA Load Mapping

Input

Channel Number

Node ID Component Coord Sys

ChanNum NodeID Component CoordSys

long long string long

1 1 FX 02 1 FY 03 1 FZ 04 1 MX 05 1 MY 06 1 MZ 07 2 FX 08 2 FY 09 2 FZ 0

10 3 FX 011 3 FY 012 3 FZ 013 3 MX 014 3 MY 015 3 MZ 0

Slice # Element Number Slice (time) Slice (point)1 2 475.520 237,7612 2 2,839.694 1,419,8483 2 2,834.046 1,417,0244 2 812.122 406,0625 2 819.568 409,7856 2 475.748 237,8757 2 3,114.642 1,557,3228 2 2,835.054 1,417,5289 2 823.900 411,95110 2 812.322 406,162


© 2018 HBM

www.hbmprenscia.com

Kenneth M. Citrin Paul Green

CAE Engineering, MANA HBM Prenscia

248‐417‐8219 248‐945‐4340

2018 ncode user group meeting –north america | february 28

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