Load, contact behavior and natural characteristics of non-pneumatic elastic wheel with local damage hinge group

Abstract: The conventional pneumatic tires have disadvantages in terms of puncture, blowout at high speed, pressure maintenance, and so on. Due to these structural inevitable weaknesses, non-pneumatic tires have been developed and are being investigated. A new non-pneumatic elastic wheel was proposed and studied to solve these problems. As an important bearing member of the non-pneumatic elastic wheel, the force of hinge group is very complex and it has a significant effect on the performance of the wheel. However, in the complex off-road driving, the hinge group has to withstand complex random load and impact load, and inevitably there will be damage failure. In order to explore the performance change of the wheel after the failure of the important bearing parts, it is necessary to study the influence of the hinge group with local damage on the performance of the non-inflated elastic wheel. In this paper, an experimental study on basic characteristics of non-pneumatic elastic wheel with local hinge group fracture damage was conducted in order to enhance the reliability. Based on tire characteristic test-bed, the tests on basic characteristics of static radical stiffness and contact behavior as well as the modal test were conducted. The wheel with local damage, one hinge group of which was disassembled, was used to simulate hinge group fracture condition in this paper. The results show that the effect of the hinge group fracture damage on the wheel load characteristics is the decrease of the radial stiffness, and it is also related to the damage position on the non-pneumatic elastic wheel. The radial stiffness of non-damaged non-pneumatic elastic wheel is 593.06 N/mm, and the corresponding values of the non-pneumatic elastic wheel with fractured hinge group on horizontal position and vertical position are 443.2 and 385.4 N/mm, respectively. Compared with non-damaged non-pneumatic elastic wheel, the numerical value of radial stiffness is reduced by 25% and 35% respectively on horizontal position and vertical position when the fractured hinge group is installed. That is to say the consistency of radial stiffness and deformation uniformity get worse for the wheel with local damage, so the poor performance of riding comfort of non-pneumatic elastic wheel appears. The influence of the hinge group fracture damage on the grounding pressure distribution is the change of grounded imprinting length and grounded area. Under the same vertical load, these 2 indicators of the non-pneumatic elastic wheel with fractured hinge group increase compared with non-damaged non-pneumatic elastic wheel. When the vertical load is 7 262 N, the imprinting length of the non-pneumatic elastic wheel with fractured hinge group on horizontal position is 138 mm, and the numerical value of non-damaged non-pneumatic elastic wheel is 120 mm. The ground imprinting length of the damaged wheel is increased by 15% compared with that of the non-damaged non-pneumatic elastic wheel. The grounded imprinting width does not change, and the value remains at 285 mm. As a result, the total grounded area of the damaged wheel also increases. The area of the non-damaged non-pneumatic elastic wheel is 34 200 mm2, and the area of damaged wheel increases to 39 330 mm2. The contact length and area of the wheel with local damage are greater than corresponding values of the non-damaged non-pneumatic elastic wheel under the same load. The influence of the hinge group fracture damage on the wheel modal test is the change of the natural frequency, the damping coefficient and the modal shape. In addition to a few orders, the natural frequency of non-damaged non-pneumatic elastic wheel is greater than that of non-pneumatic elastic wheel with local damage hinge group, and the damping coefficient of the most of non-damaged non-pneumatic elastic wheel is less than that of non-pneumatic elastic wheel with local damage hinge group. The value of the amplitude of modes gets smaller for the non-pneumatic elastic wheel with local damage hinge group.