Many of the design criteria for commercial vans and trucks differ significantly from those of small passenger vehicles. The requirements for robustness and long service performance require particular attention to the strength aspects of these vehicles. In particular, owing to high loads from cargo payload and the long hours in service, fatigue plays a major role in the structural design assessment. Further, since these vehicles are places of work for the driver, the vibration-free design of seats and acceptable noise comfort are paramount to the market success of such vehicles. With a team of engineers specialized in the design analysis from vans to heavy trucks, CDH AG assists its customers to meet the high demands on commercial vehicle structures.

Vibration Comfort and Acoustics

Since a commercial vehicle is the work-place for the driver, special attention must be paid to the NVH comfort of these vehicles. The vibration that the driver experiences through contact with the seat, floor and steering wheel and the perception of low-frequency noise must kept to a minimum. Various types of NVH analysis are performed in the virtual design stage in order to ensure that these comfort related design targets are achieved in the actual vehicle.

FULL VEHICLE VIBRATION AND ACOUSTIC ANALYSIS

• Modeling of drive-line, chassis, body, cabin, trimming and air cavity.
• Low frequency analysis with excitation from engine forces, road etc. to predict tactile vibration responses at vehicle comfort-points. 
• Low frequency analysis with excitation from engine forces, road etc. to predict tactile acoustic response (SPL) at comfort-points such as driver ear position.
• Optimization of complete vehicle NVH performance.

BODY AND DRIVER CABIN ANALYSES

• Linear static stiffness and strength calculations on body or driver cabin
• Calculation of natural frequencies and vibration mode shapes and the dynamic stiffness of body/cabin attachment points
• Numerical optimization to minimise weight and satisfy NVH design targets.

AUXILIARY COMPONENT ANALYSES

• Strength analyses of individual machine components such as brake fluid flexible tubes
• Optimization at component level, e.g. optimization of leaf-spring layout

ACOUSTIC ANALYSIS OF AUXILIARY COMPONENTS

• Assessment and minimization of noise radiation from individual components (such as engine and gearbox). These analyses are conducted using CDH in-house developed boundary element analysis and numerical optimization techniques