Design and Analysis of Automated Truck Cabin Suspension System
The suspension system is used to isolate the chassis from the shock loads due to irregularities of the road surface. This must be handled without impairing the stability, steering or general handling of the vehicle. Suspension system for the cab is placed between the chassis using bolts. The loads coming from the floor and the chassis are taken by the suspension. Constraint equations and couples are used to connect various regions of the suspension system. The loads are applied on the leaf spring of the suspension system. Static analysis is made to study the deflection of the leaf spring. Modal analysis is made to check the natural frequencies. Harmonic analysis is also done to plot various graphs between frequency and amplitude. Results and discussions are made from the results obtained from the Ansys and conclusions are given and scope for future work is also given.
To be able to evaluate any passive or (semi- )active suspension system, models which accurately describe the dynamic behavior of the vehicle and suspension are often desirable. For a fair comparison of various suspension concepts, they should be applied to the same vehicle model. Furthermore it is important that the variables of the suspension component models are chosen such that the suspension systems perform optimal with respect to the same objectives and constraints.
When investigating a truck cabin suspension system to improve driver comfort, bounded by working space constraints, the most important function of the vehicle model is to describe the cabin motion caused by to road irregularities and other disturbances.
Besides the vehicle model, it is important to have representative suspension component models at disposal. A passive suspension system consists of passive elements like (linear or nonlinear) springs and dampers bump stops and possibly inerter. It may be worthwhile to evaluate the performance of some of these suspension concepts in a cabin suspension system. Semi-active suspension components can be regarded as essentially passive, meaning they can only store or dissipate energy from the system but the automated suspension components can be regarded as essentially active that is, they can store energy and dissipate energy from the system simultaneously.
However, a relatively small amount of external energy can be used to change its characteristics. By doing so, the performance of the suspension system can be improved. These automated suspension components are typically variable rate springs and dampers. Briefing a Component of Suspension System The performance of the suspension system can be improved by reducing the impact of vibrations on the cabin system which are caused by various factors as discussed earlier. So now let us consider in improving the performance of a cabin suspension system by a performing an analysis on a leaf spring which is a major component of a suspension system.
There are four basic designs of leaf spring that are used in stock car racing.
The Mono-Leaf Spring
Parabolic Leaf Springs
Composite Leaf Springs
Design of Leaf Spring
Considering several types of vehicles that have leaf springs and different loads on them, various kinds of composite leaf spring have been developed. In the case of multi- leaf composite leaf spring, the interleaf spring friction plays a spoil spot in damage tolerance. It has to be studied carefully. In the present work, only a leaf spring with constant thickness, constant width design is analyzed.
The following cross-sections of leaf spring for manufacturing easiness are considered.
1. Constant thickness, constant width design
2. Constant thickness, varying width design
3. Varying width, varying width design.
Analysis on Leaf Spring
The leaf spring modeled in AutoCAD Inventor was imported to ANSYS in IGES format. Since leaf spring was modeled as a solid, solid element named SOLID187 was used to mesh the model. SOLID187 element is a higher order3-D, 10-node element.
SOLID187 has a quadratic displacement behavior and is well suited to modeling irregular meshes (such as those produced from various CAD/CAM systems). The element is defined by10 nodes having three degrees of freedom at each node: translations in the nodal x, y, and z directions.
Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.