Search results

The purpose of this paper is to provide sound understanding of the mutual interactions of the major leaf spring design parameters and their effects on both the stress behavior of the designed leaf and the steering behavior of the vehicle.

Finite elements analyses have been performed referring to the design of a high performance monoleaf spring used for the suspension of the front axle of a serial heavy truck. Design parameters like eye type, eye lever, spring rate and arm rate difference have been parametrically examined regarding the stress performance and their influence on the wheel joint kinematics. The effect of each design parameter is exhibited both qualitatively and quantitatively.

Eye lever and eye type affect significantly the wheel joint kinematics and therewith the steering behavior of the vehicle. Spring rate and arm rate difference affect solely the stress performance of the leaf spring.

Design engineers may use the outcomes of this research as a guide to achieve optimal leaf spring design ensuring its operational strength in conjunction with accurate steering performance of the vehicle.

The international literature contains only few, mostly qualitative data regarding the effect of single design parameters on the leaf spring and the corresponding axle kinematics. The present work contains a comprehensive and systematic study of all major leaf spring design parameters, and reveals their effect on both the stress behavior and the steering behavior of the vehicle qualitatively and quantitatively.

The purpose of this paper is to develop a FE based modeling procedure for describing the mechanical behavior of high‐performance leaf springs made of high‐strength steels under damaging driving manoeuvres.

The type and number of finite elements over the thickness of leaves, as well as the definition of contact, friction and clamping conditions, have been investigated to describe the mechanical behavior in an accurate and time‐effective manner. The proposed modeling procedure is applied on a multi‐leaf spring providing complex geometry and kinematics during operation. The calculation accuracy is verified based on experimental stress results.

A FE based modeling procedure is developed to describe the kinematics and mechanical behavior of high‐performance leaf springs subjected till up to extreme driving loads. Comparison of numerically determined stress distributions with corresponding experimental results for a serial front axle multi‐leaf spring providing complex geometry and subjected to vertical and braking loads confirms high calculation accuracy.

The proposed FE based model is restricted to linear elastic material behavior, which is, however, reasonable for the high‐strength steels used for leaf spring applications.

The proposed FE procedure can be applied for the design and optimization of automotive leaf springs, especially for trucks.

The proposed procedure is simple and can be applied in a very early design stage. It is able to describe accurately the leaf behavior, especially the stiffness and stress response under the most significant driving events. It goes far beyond today's practice for leaf spring design, which is based on analytical methods not covering complex axle and steering kinematics, large deformations and non‐linearities.

The paper aims to illustrate the application of a state-of-the-art fatigue prediction concept (IIW recommendations) to the ADR calculation requirements, in order to include failure-critical weld details to the strength assessment of road tanks. The level of calculation accuracy and, therefore, safety of such structures transporting dangerous goods can be substantially increased.

A case study of a 2-compartment aluminum alloy LBGF tank used for the transportation of gasoline/petroleum products is conducted adopting the meshing directives of the structural hot spot stress concept (SHSSC) of the IIW recommendations for the weld details of the structure. The stresses on the prescribed Hot Spots are extracted from the solutions of each load case described in the ADR legislation and assessed both in terms of static strength according to EN 14286 and fatigue strength using the standardized IIW assessment curves (FAT curves).

The detailed analysis of the road tank has successfully allocated the failure critical points of the structure. Additionally it has illustrated the ability of the embedded fatigue concept to accurately calculate the stresses which can later be used for the durability evaluation, providing that at least some operational load spectra become available.

The use of a global meshing and calculation concept offers a relatively limited accuracy level considering any individual weld detail. On the other hand, it offers a sufficient overview of the whole structure with minimum effort and costs.

Time-consuming integrity inspections of road tanks can be minimized, as the failure critical locations are identified and therefore easily monitored. Furthermore, the transformation of the fatigue life prediction issued by the proposed calculation into actual operational time may be used to determine realistic time intervals between service pauses required for the safe operation of such structures.

The present study constitutes the first approach of embedding the SHSSC into the calculation of large-scale structures such as road tanks and verifies the applicability of this concept beyond simple geometries and load cases.