Hydraulic cylinder is the core of construction machinery remanufacturing. Remanufacturing enterprises in China are eager for finding out feasible remanufacturing process for the used hydraulic cylinder, which main failure mode is scratch on the surface of hydraulic cylinder bore. Causes of failure mode and feasibility of honing process applied on of hydraulic cylinder bore remanufacturing are analyzed considering three factors: little machining allowance, overlapping curve and high surface quality. The honing process technology is presented, including selection of honing machine, honing oilstone, honing oil and process parameters of course honing, micro honing and polishing, and honing process for remanufacturing. A case of applying honing process on boom cylinder bore remanufacturing is given and proved to be feasible in practice.

Propose a simulation method of finding the optimized gravel radius of the arrester bed on truck escape ramp in order to obtain the shortest stopping distance of runaway vehicle. A simulation model between gravel and tire is generated and calibrated by PFC2D (Particle Flow Code in two-dimensions) respectively. Utilize the model to simulate the relationship between radius and stopping distance at varied slopes and initial vehicle speeds. Simulation shows that whatever the slopes and the speeds are, the shortest stopping distance corresponds to gravel radius range is between 8.3mm and 15.7mm, that average radius is 12mm. The average radius is basically consistent with the ideal gravel radius 12.7mm, which indicates that the method is effective and could be a substitute for the full-scale test.

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Due to imperfect design norms and guidelines for China’s truck escape ramp, previous studies have not been able to reflect the effect of wheel subsidence process on the deceleration of runaway vehicles. A discrete element method was used to establish an aggregate discrete element and a wheel discrete element. The three-dimensional discrete element model for an aggregate-wheel combination was established based on a particle flow code in three dimensions on a software platform using the “FISH” language. The microscopic parameters of the aggregate discrete element particles and wheel discrete element particles were calibrated using a simulated static triaxial compression test and real vehicle test data, respectively. Four sets of numerical simulation tests were designed for analyzing the influence of the aggregate diameter, grade of the arrester bed, truckload, and entry speed on the wheel subsidence depth and stopping distance of runaway vehicles. The results indicate that the smaller the aggregate diameter and entry speed and the greater the truckload and grade of the arrester bed, the more easily the wheel falls into the gravel aggregate, the better the deceleration effect, and the smaller the stopping distance. As the wheel subsidence depth increases, the speed at the unit stopping distance decreases more quickly. The maximum subsidence depth mainly depends on the truckload. The research results can provide a theoretical basis for the design of the arrester bed length and the thickness of the aggregate pavement in a truck escape ramp.

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