Powertrain session atc_2015

OptiStruct for PT NVH

Copyright © 2015 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.

Full Vehicle NVH

Powertrain NVH

Body/Chassis NVH

Squeak & RattleWind Noise

Radiated NoiseRide NVH

Brake NVH

OptiStruct solution for NVH

Full Vehicle NVH

Powertrain NVH

Body/Chassis NVH

Squeak & RattleWind Noise

Radiated NoiseRide NVH

Brake NVH


A comprehensive set of NVH solutions for upfront problem solving

• Full frequency, multi-physics NVH simulation capabilities

• Superior user experience in a highly integrated, automated framework

• Population performance based assessment, instead of single sample

• Optimization based design, instead of experience based design

OptiStruct for Powertrain NVH


• A comprehensive high-performance FE-solver

• NVH Solutions

• Normal modes

• Preloaded normal modes

• Complex eigenvalue

• Frequency response

• Random Response

• Transient Analysis

• Acoustic Analysis

• Rotor Dynamics

• Solutions are “ready for optimization”

• Interfaces to AMSES and FastFRS



• OptiStruct AMSES fast eigenvalue solver

• Calculate thousands of modes for millions of dof’s

• Handles unconnected structures

• Can be used with enforced motion (SPCD)

• OptiStruct FASTFR frequency response

solver

• Include thousands of modes with viscous and/or

structural damping

• Works with frequency dependent materials

• PARAM,FASTFR,(AUTO/ON/OFF)

• No additional cost for AMSES or FASTFR


0 20000 40000 60000 80000

AM

SE

SLa

nczo

selapsed time (s)

AMSES VS Lanczos for Modal FRF solution

EigenSolution

StructralDamping

Other


Total Sound Power

• The total sound power is the rate of change of sound energy with time in the domain

of reference

• The total sound power due to all the source grids can be calculated at a microphone

location for each frequency as follows


Sound Pressure

• Radiated Sound Output can be requested for grid points on the structural surface and

in the exterior acoustic field. Grid points are used to represent microphones to record

the radiated sound, sound power, and sound intensity.


Sound Intensity

• The total complex intensity vector is the sound power per unit area. The sound

intensity can be defined as a product of sound pressure and the particle velocity

vector

• For multiple source grids, the total sound intensity at a microphone location for each

frequency is given as follows


Equivalent Radiated Power

• Computation of the equivalent radiated power (ERP) is a simplified method to gain

information about maximum dynamic radiation of panels for excitations in frequency

response analysis.

• The ERP output of a panel is calculated as half the normal velocity squared of each grid

multiplied by the associated area of each grid on the panel.


Noise and Vibrations

• Frequency Dependant Materials

• Direct and modal FRF

• MATFx data

• Rotor Dynamics Analysis

• Modal frequency response and

complex eigenvalue analyses

• Synchronous and asynchronous

analyses

• Output data generation for the

Campbell diagram (critical speeds)

• Poro-elastic (BIOT) Materials

• MATPE data


• Fast and accurate generation of AVL/EXCITE input data

• Condensed matrices

• FE model information

• Grid Displacement and Stress

• Directly coded in OptiStruct:

• No DMAP, scripts, or macros required

• AVL/EXCITE GUI for easy problem setup

• Post AVL/EXCITE analysis to recover

• Transient or frequency response stress and strain

• Displacements, Velocities, and Accelerations in seconds

• AMSES can be use for large problems

OptiStruct Interface to AVL/EXCITE


Post processing

.fem or .bdf

Model data/ matrices in ASCII or

binary format (.OUT2, .OUT4, …)

.exb

.INP4

.h3d or op2

Flexbody.h3d

Model building/ conversion

MBD analysis

Stress and Strain

Recovery

Flexible Body Generation

.exb Generation

HyperMesh

Simlab

OptiStruct

AVL/EXCITE

AVL/EXCITE

OptiStruct

Process scheme – OptiStruct AVL/EXCITE Coupling


Optimization


• ERP available as an internal response in OptiStruct

• Can also be applied to frequency sub-ranges

• Topology optimization successfully applied to identify internal rib

structure using ERP responses

• Optimized design proposal shows a significant improvement in the ERP

responses

Summary


Postprocessing


The goal of the Equivalent Radiated Sound Utility is to post process results of

exterior structure-borne radiated sound

- ERP H3D and PCH

- Radiated Sound (Power / Pressure) H3D

Equivalent Radiated Sound Utility


Order analysis is a technique for analyzing noise and vibration signals in rotating or reciprocating

machinery. Examples include aircraft and automotive engines, compressors, turbines, and pumps.

Order analysis is an easy way to separate structural phenomena (resonances, fixed frequencies)

from the rotational ones (variable frequencies). When presented in a frequency vs. rpm plot, you can

see the resonances as parallel lines to the rpm axis and rotating frequencies as lines increasing or

decreasing with speed (rpm).

Engine Order Analysis


Analyze

• Worst case scenario

• Critical components and locations

exceeding the allowed thresholds

• Effects of the latest design change

Automated Reporting Solution

Communicate

• Share findings frequently

• Right level of information

• Consistent appearance

Challenge

Large amount of data/results

Laborious repetitive tasks


Set-up

0.5 h

Load Template, apply contour and adjust legend

per component

Refine/match ID’s and part/component names

Verify model definition, e.g. material, properties

Automated Reporting Solution

Assessment

3.5 h

Hotspot Finder or Measure Panel: Mark critical result

locations

Adjust to best view, create and save screenshot

Review each component and identify critical

components

Report

2 h

Import all screenshots into PPT master

Create Overview Table

Rearrange/format slides/layout


THANK YOU

Documents

Powertrain session atc_2015