Automotive NVH (Noise, Vibration, and Harshness) Analysis using Abaqus

Training for Automotive NVH requires a specialized focus on frequency-domain dynamics and the interaction between structural components and acoustic cavities. Abaqus provides a robust suite of tools for these simulations, ranging from simple component modal analysis to full-vehicle vibro-acoustics.

Course Objective

Vehicle NVH (Noise, Vibration, and Harshness) is typically perceived as a reflection of vehicle quality. As a result, the primary goal of NVH design is to optimize the vehicle’s energy absorption. Large-scale linear dynamics are typically employed in NVH analysis. This course focuses on applying the linear dynamics capabilities in Abaqus to NVH-related simulation.

Topics include:

Fundamental Dynamics & Modal Analysis

• Natural frequency extraction: Using the Lanczos or AMS (Automated Multi-Level Substructuring) eigensolver to find resonant frequencies.
• Nonlinear pre-loading effects: Understanding how bolt pretension or gravity affects the stiffness and vibration modes of a chassis.
• Damping models: Implementing Rayleigh, structural, and modal damping to represent energy loss accurately.
• Steady-State Dynamics (SSD)
  • Frequency Response Functions (FRF): Calculating the structural response to harmonic excitations (e.g., engine firing pulses or unbalanced rotating parts).
  • Direct vs. Modal SSD: Choosing between high-accuracy direct integration and high-efficiency modal superposition.
  • Base Motion: Simulating shaker table tests or road-induced excitations through the suspension.
• Coupled Structural-Acoustic Analysis
  • Sound radiation analysis (acoustics)
  • Acoustic Cavity Modeling: Defining the interior air volume of a vehicle cabin using acoustic elements.
  • Surface-based Tie Constraints: Connecting structural meshes to acoustic meshes efficiently.
• Brake squeal analysis: Using Complex Eigenvalue Analysis to predict instabilities and high-frequency noise in braking systems.
• Constraints and connections
• Material modeling and damping
• Substructures (Superelements): Reducing large assemblies (like an engine) into a simplified mathematical representation to save time.
• Advanced NVH postprocessing (via plug-ins)
• Conversion of Nastran to Abaqus (optional)

Software Focus Areas

• Abaqus/Standard: The primary solver for linear and frequency-domain NVH.
• Abaqus/CAE Visualization: Using the Visualization module to generate polar plots, XY plots of FRFs, and animations of complex mode shapes.

Who Should Attend

While this course is primarily intended for engineers with experience using Abaqus, it includes appendix material to assist engineers with finite element knowledge who are new to Abaqus and Abaqus/CAE. The additional appendix material is included to guide users in translating Nastran models to Abaqus. Please contact the hosting SIMULA office to learn if time has been allotted to cover the appendix material during a particular offering of this seminar.

Course Overview

The overview provides details of the topics covered in each lecture. Please note that the actual course agenda may vary depending on location.

• Download the course overview