Search Results

The main reason for the definition of leaf springs as safety parts is that even the smallest mistake in its functioning can cause severe accidents. It is imperative to ensure the endurance of leaf springs under high deformation and stress. In this reference study, we examine deviations resulting from production and design variations known as” noise factor” which can affect the fatigue life of a parabolic leaf spring. It will be a mistake to evaluate the design roughly with the stress levels on the layer. It has been described in this study with relevant examples that the leaf spring with 1550 N/mm2 tensile strength may be broken under much lower stress levels if it is exposed to dynamic loads.

Parabolic leaf springs are used as safety parts in heavy/ light commercial vehicles. When designing leaf springs, one must complete the evaluation from the perspectives of fatigue life and durability in order to ensure optimization of the design. After the initial design, rather than trying to establish optimization by producing prototypes by trial and error method, using the virtual prototype process to achieve design optimization, thereby reducing the costs will offer competitive advantage for both suppliers and original equipment manufacturers in the global market. In a reference study carried out in a partnership with Ford Otosan, the finite element methodology was used to verify the design of a 4- layered parabolic leaf spring and a multi-parabolic spring designed as its alternative. The stress distribution on layers during vertical, loaded and windup moment was examined.

It has been a significant challenge to reduce weights of the vehicles to satisfy the regulations that require development of environmentally-safe vehicles with low CO2 emissions. The conventional leaf springs, designed for the optimized performance together with safety factors, are made of steel. However, it is considered that the steel leaf springs are replaced by lighter ones in order to fulfill the specified requirements. Fiber reinforced composite materials with polymer based matrix offer a great potential for manufacturing leaf springs with lightweight, high mechanical and fatigue performance. Therefore, leaf spring manufacturers have great interest in those materials to replace steel parts with the composite ones and an increasing number of studies have been published in the literature in recent years. In this study, fiber reinforced composite compared with steel leaf springs based on endurance rig tests will be presented.