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Altair > Case Studies > Simulating Squeak & Rattle Phenomena During the Development of a Truck Cabin: A Case Study

Simulating Squeak & Rattle Phenomena During the Development of a Truck Cabin: A Case Study

Technology Category

Analytics & Modeling - Digital Twin / Simulation
Infrastructure as a Service (IaaS) - Virtual Private Cloud

Applicable Industries

Automotive
Specialty Vehicles

Applicable Functions

Product Research & Development
Quality Assurance

Use Cases

Time Sensitive Networking
Virtual Reality

Services

Testing & Certification

The Challenge

Scania CV AB, a leading manufacturer of trucks and buses, was facing a challenge in accurately simulating squeak and rattle noise within a truck cabin. Squeak and rattle are two phenomena observed when two parts of an assembly are in relative motion due to a specific excitation load. In the automotive industry, these phenomena are studied to reduce cabin noise and improve ride quality and comfort for occupants. Historically, Scania’s Cabin Development Department did not perform this kind of simulation. The team had to rely on tolerance calculations and the choice of materials to reduce the risk of squeak and rattle. When first prototypes became available, iterations were made to fix and correct the final design to solve the noise issues. To reduce development time and cut down on iterative changes, a solution was needed that enabled a simulation-driven design process during the early stages of the cabin development cycle.

About The Customer

Scania CV AB is one of the world’s leading manufacturers of trucks and buses for heavy transport applications, and of industrial and marine engines. A growing portion of the company’s operation consists of products and services in the financial and service sectors, assuring Scania customers have cost-effective transport solutions and maximum uptime. Employing 32,800 people, Scania operates in around 100 countries. Research and development activities are concentrated in Sweden, while production takes place in Europe and South America, with facilities for global interchange of both components and complete vehicles. In 2012, invoiced sales totaled SEK 79.6 billion and net income amounted to SEK 8.3 billion.

The Solution

Scania partnered with LeanNova Engineering AB and Altair ProductDesign to assist with the development process for a Scania truck cabin. The solution involved using Altair's Squeak and Rattle Director (SNRD) to simulate the squeak and rattle phenomena. Simulations can be performed very early in the design process, leading to increased right first time designs and reduced need for physical testing. Simulations also lead to significant time reduction, allowing engineers to perform more analyses in a timely manner and with limited resources. During a 16 month period, two full design loops and a number of design studies were performed on-site at Scania. The first step involved modal correlation of the plastic parts from an existing cockpit to improve the material database for future simulations. The second step was to build up a full vehicle model for various types of cabin, and by applying loads from road test measurements, calculate the relative displacement at defined interfaces.

Operational Impact

The use of Altair's Squeak and Rattle Director (SNRD) led to significant improvements in Scania's product development process. The simulation methodology provided valuable support to the tolerance calculations performed by Scania's analysts. The output from SNRD delivered valuable input for the designers to help find better attachments and boundary conditions to their parts. In addition, the tolerance analyst benefits from the dynamic tolerance calculated in SNRD to include in the static tolerance calculation. This resulted in improved product quality by identifying risk areas and reducing the need for physical testing and iterative changes.

Quantitative Benefit