Home
Full Vehicle NVH
Access the Assemble, Analyze, NVH Tools, NVH Post, and Physics AI ribbons.
Post-Processing and Diagnostics
Define radiation conditions and create emissivity models.
Modal FRF
Calculate a frequency response based on modal results.
Modal FRF - Plot Response
Plot the response options.

Welcome
What's New
View new features for HyperMesh NVH 2024.
Get Started
Learn the basics and discover the workspace.
Tutorials
Discover NVH functionality with interactive tutorials.
Full Vehicle NVH
Access the Assemble, Analyze, NVH Tools, NVH Post, and Physics AI ribbons.
- Assembly
  Learn how to create, open, import and save models.
- Analysis
  Set up the simulation model, materials, domains and boundaries.
- NVH Tools
- Prepare Module
  Create, organize and manage the CAE parts.
- Post-Processing and Diagnostics
  Define radiation conditions and create emissivity models.
  - Load an NVH Utility
  - Integrated Diagnostics
    Calculate a response, perform contribution analysis, plot results, and perform diagnostic studies and study response changes.
  - Modal Participation
    Plot modal/panel participation curves from an OptiStruct .h3d file or an MSC Nastran .f06/.pch file.
  - Grid Participation
    The Grid Participation utility allows you to plot panel grid participation results and then use advanced scaling contour capabilities to isolate key contributing areas.
  - Energy Distribution
    Visualize the distribution of energy within a full vehicle NVH model, as a way to understand what components are dominating the vehicle response.
  - Transfer Path Analysis
    Identifies the complex contribution of the excited structure through attachment points to a response in the responding structure.
  - Design Sensitivity Analysis
    Design sensitivity represents a change in response with respect to a change in a design variable, which is typically used for optimization.
  - Order Analysis
    Generates and post-processes engine order related data from an OptiStruct or Nastran frequency response analysis that contains either RPM-based loading subcases or order-based loading subcases.
  - Modal FRF
    Calculate a frequency response based on modal results.
    - Modal FRF - Define Modes
      Select the modes.
    - Modal FRF - Define Loads
      After selecting the modes from the Define Modes tab, select nodes at which unit excitations or actual excitations can be applied.
    - Modal FRF - Define Response
      Calculate and export responses.
    - Modal FRF - Plot Response
      Plot the response options.
    - Modal FRF - Plot Diagnostics
      Plot the diagnostics.
  - Model Correlation
    The Model Correlation utility determines the degree of similarity or correlation between two sets of results.
  - Radiated Sound
    The Equivalent Radiated Sound utility post-processes the results of exterior structure-borne radiated sound.
  - Global Modes
    Identifies global modes from an OptiStruct or Nastran modal analysis.
  - Flow Induced Noise/General Signal Processing
    The General Signal Processing utility processes the time domain pressure results from CFD simulations and visualizes the results in both the time and frequency domain.
  - Green House Noise
    Post-process the pressure result of a vehicle panel obtained from ultraFluidX.
  - Mount Optimization
    Predicts powertrain rigid body mode frequencies and kinetic energy distribution, which play a critical role in optimizing the mount stiffness and layout configuration, by decoupling powertrain rigid body modes and reducing vibration transmission.
  - Optimization, RBDO
    Optimizes sensitive parameters for multiple sample analysis results using the RBDO or Deterministic approach.
  - Multiple Sample Analysis
    Post-process results from a Multiple Sample Analysis, including plotting a spread of responses (+/-95% and mean).
  - Deterministic Optimization
    Reads results from an OptiStruct optimization run and processes the results to review the overlay of the NVH responses, baseline versus optimized. Compare changes in the design variable values, baseline versus optimized.
  - Display Options
    Customize plots using the following options
  - Filter Contributors
    Filters contributors to a smaller set of data.
High Frequency NVH
High frequency NVH is an implementation of Statistical Energy Analysis (SEA), and is used to predict and analyze the vibration and acoustic response of complex dynamic systems.
Squeak and Rattle
Create and evaluate evaluation lines and optimize interfaces to eliminate squeak and rattle issues.

View All Altair HyperWorks Help

Modal FRF - Plot Response

Plot the response options.

Response File: Information from the result PUNCH file with FRF results.
Subcase: Select a subcase from the drop-down menu.
Result type: Select the response type, displacement, velocity, and acceleration.
Response ID: Select the grid ID of the response from the drop-down menu.
Direction component: Select the component of the response grid ID from the drop-down menu.
Display Options: The Display Options dialog allows you to customize the response plot, including scale, weighting, and the plot layout.
Load Response: Once the result selection options are complete, select Load Response to display the response curve. Additionally, right-click in the plot window to convert between the result types and calculate the derived quantities based on a user-defined frequency range (Acceleration to Displacement, Acceleration to Velocity, and vice versa). See Figure 2.

Figure 1. NVH Utilities Browser - Modal FRF - Model tab/Plot Response subtab

Figure 2. Response curves for the FRF computed from modal results