Papers by Author: Li Bo Cao

Abstract: In this study, an occupant restraint system model of a production SUV developed in MADYMO software was used for crash simulations. Component tests were conducted to obtain the parameters of seatbelt and seat. Parameters of airbag were obtained by tank tests and the airbag model was validated by headform drop tests. The occupant restraint system model was validated against results from real vehicle crash tests. Robust design method was adopted for sensitivity analysis and system optimization. Two parameters, spool effect of the seatbelt and mass flow of the airbag, were studied to improve the occupant protection. Better protection performance has been obtained using optimized parameters, and the robustness of the optimized result was proved by robustness assessment.

Abstract: To improve the precision of side impact simulation, MDB model with taper section beam element was established and validated under the GB20071-2006 regulation. The MDB model was used to simulate a side impact test with a production car. The velocities of five key points on the B pillar and the door were outputted and compared with the test data. Numerical results show that the MDB model which based on taper section beam element can meet the requirements of the regulation and is in line with the test data, thus getting a higher accuracy and better simulation application value.

Abstract: This paper presents a pneumatic energy absorption system which can extend the energy-absorption beam automatically just before crash. The system consists of thin-shell energy absorption structure, pneumatic equipment and control system. When the control system detectives a crash accident is unavoidable, the pneumatic equipment will extend the energy absorption beam which is fixed in thin-shell energy absorption structure immediately to increase energy absorption space. This system has been equipped on a mass produced bus, and it indicates that the length of energy absorption space can be increased more than 230 mm instantaneously before a crash accident occurs. The time used to extend the energy absorption beam is less than 100ms.

Abstract: According to GB/T 20913-2007 regulation, the finite element model of the offset deformable barrier (ODB) was built with beam and shell elements, and validated in the simulation of quasi-static compression test. In order to analyze the local deformation characteristics of the ODB model, a sled test was designed. A cylinder impactor of 110 mm in diameter was welded in front of the sled. It was used to impact the fixed ODB. The simulation model of this test was also built. The acceleration of the sled and the deformation of the ODB were measured in the test and compared with the simulation data. The results show that the ODB model with beam elements not only satisfies the demands of the regulations, but also has good local deformation characteristics. The efficiency of computing can be improved obviously with beam elements.

Abstract: According to GB 20071-2006 regulation, the finite element model of aluminum honeycomb block was built with beam elements, and the corresponding moving deformable barrier (MDB) model was validated. Side impacts between a vehicle and the MDBs which were set up with beam elements and solid elements respectively, were simulated. The velocities of five key points on the B pillar and the door were measured and compared with the test data. The results show that the demands of the regulations could be achieved by the MDB with beam elements, while at the same time, the efficiency of computing is improved and better local characteristic is obtained.

Abstract: Tooth broken, oil leaking and bearing burnt have influenced the original running of a 45T mining car which adopted one two-class gear reducer. In order to solve these problems, a three-class gear reducer was developed and its strength and stiffness were validated by using experience formulas and FEM. The sample of the three-class gear reducer was manufactured and tested in practical work for more than a half year. The results show that the three-class reducer works well, and the problems occurred in the two-class one can be resolved.

Abstract: In practice, the large lever, connecting bolt, small lever pin, small lever and front support pin of the brake system of an electric locomotive often broken or fractured. According to the dynamic and static analysis, the maximum stress values of above-mentioned structures were close or exceeded their yield stress. It was consistent with the actual. Based on the result of finite element analysis, combined with the need of manufacturing process, the structure of those components was improved. Simulation and experiment results have indicated that the improved braking system has enough strength and stiffness.

Abstract: The S beam of a production SUV appeared instable deformation in frontal crash test, which was not beneficial to occupant protection. So the deformation of S beam should be controlled to improve the crashworthiness. Inner improvement structures were proposed according to the prototype S beam. A frontal crash FE model and a multi-rigid body model were developed and validated to investigate the crash safety of frontal impact. The influences of the improvements to the deformation of S beam and the energy absorption of longitudinal beams were analyzed by the FE model, and the injury risks of head and thoraces were analyzed by the multi-rigid body model. The better improvement structure was adopted in the frame for the crash test to validate the effectiveness of improved scheme, and the result shows better crash performance of frontal impact for prototype vehicle. Meanwhile, simulation study on crash safety of 40% offset crash were also conducted, which indicated that improved scheme was also beneficial for crash safety of 40% offset crash.

Abstract: A new integrated child safety seat is presented in this paper. The seat is a two-mode seat for a motor vehicle cooperable with an adult seat belt assembly to provide two modes operation including an adult seat mode and a child seat mode. The seat locates in the center of the rear seat. The structure of the seat was designed in detail. The height of the booster of the seat can be adjusted continuously according to the seated shoulder height of the child passenger. The depth of booster cushion also can be changed according to the size of the passenger. The sled test with the seat was conducted. The seat simulation models with different booster heights were developed using MADYMO software and validated. Then, these models were used to study the performance of the seat in frontal impact. Some key parameters of the seat were studied in simulation test. The results of the test and simulation show that the seat can provide effective protection for the children aged from 3 to 10 years in frontal impact.

Abstract: In this article, seven frontal impact simulation models with same restraint system and different human body models were established through the use of multi-body kinematics software MADYMO. The injuries in head, chest and femurs of different human models and the differences of these injuries were analyzed in detail. The weighted injury criterion was adopted to evaluate the overall injuries of different human body models. The results shows that the injury risk of smaller human body is much higher than the taller human body, and existing occupant restraint system that protects the 50th percentile American occupant well protects other size occupant poorly.