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Multi-axle dynamic steering system of truck-howitzer

LI Yanliang, GAO Xiuhua, ZHANG Chunqiu, SUN Yubo

《机械工程前沿（英文）》 2008年第3卷第1期页码 44-49 doi: 10.1007/s11465-008-0002-9

摘要： A two-degree-of-freedom (2-DOF) steering model of multi-axle vehicle was established. The steering center position, the relationship between the steering angle and the vehicle velocity, and the minimum turn radius were deduced on the basis of the proportional control with a zero sideslip angle. Results indicate that the system stability is decided by the vehicle barycenter position and the lateral stiffness of a tire. Under this control, the steady value of the lateral acceleration is obviously diminished and the yaw angular velocity changes little under any vehicle velocity. The system rapidly responds, the vehicle smoothly steers, and its handling stability is prominently improved.

关键词： multi-axle acceleration relationship smoothly handling stability

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New technique of precision necking for long tubes with variable wall thickness

Yongqiang GUO, Chunguo XU, Jingtao HAN, Zhengyu WANG

《机械工程前沿（英文）》 2020年第15卷第4期页码 622-630 doi: 10.1007/s11465-019-0565-7

摘要： This study analyzed the deformation law of rear axles with variable wall thickness under bidirectional horizontal extrusion and found that necking was accompanied by upsetting deformation through theoretical calculation, numerical simulation, and experimental research. The sequence and occurrence of necking and upsetting deformations were obtained. A theory of deformation was proposed by controlling the distribution of temperature field. Effective processes to control the wall thickness of rear axle at different positions were also proposed. The ultimate limit deformation with a necking coefficient of 0.68 could be achieved using the temperature gradient coefficient. A new technology of two-step heating and two-step extrusion for a 13 t rear axle was developed, qualified test samples were obtained, and suggestions for further industrial application were put forward.

关键词： extrusion rear axle necking coefficient temperature gradient

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Ancient road transport devices: Developments from the Bronze Age to the Roman Empire

Cesare ROSSI,Thomas G. CHONDROS,Kypros F. MILIDONIS,Sergio SAVINO,Flavio RUSSO

《机械工程前沿（英文）》 2016年第11卷第1期页码 12-25 doi: 10.1007/s11465-015-0358-6

摘要：

The development of transportation systems has significantly enhanced the welfare and modernization of society. Wooden vehicles pulled by animals have been used for land transportation since the early Bronze Age. Whole-body gharries with rigid wheels pulled by oxen appeared in Crete by 2000 BC or earlier. Horses originating from the East were depicted in early Cretan seal-rings of the same period. The two-wheeled horse-drawn chariot was one of the most important inventions in history. This vehicle provided humanity its first concept of personal transport and was the key technology of war for 2000 years. Chariots of Mycenaean and Archaic Greece with light and flexible four-spoked wheels acting as spring suspensions were depicted in vase paintings. The development of this vehicle incorporated the seeds of a primitive design activity and was important for engineering. The Trojan horse since 1194 BC and the helepolis since 700 BC were the first known machines on a wheeled base transported by horses or self-powered. Ancient engineers invented bearings lubricated with fat, and Romans introduced the ancestors of ball bearings for their wagons and carts. The historic evolution of wheeled transportation systems, along with early traction, suspension, and braking systems, is presented in this paper. Analytical and numerical methods are incorporated to analyze the most conceivable loading situations of typically reconstructed wheeled transportation systems in ancient times. Traction requirements both for horse-driven machines and the power for internal motors are also analyzed. This study can serve as a basis for further development of detailed reconstruction of transportation systems in antiquity.

关键词： transportation wheel spoke cart axle bearing

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A filtering-based bridge weigh-in-motion system on a continuous multi-girder bridge considering the influence lines of different lanes

Hanli WU, Hua ZHAO, Jenny LIU, Zhentao HU

《结构与土木工程前沿（英文）》 2020年第14卷第5期页码 1232-1246 doi: 10.1007/s11709-020-0653-0

摘要： A real-time vehicle monitoring is crucial for effective bridge maintenance and traffic management because overloaded vehicles can cause damage to bridges, and in some extreme cases, it will directly lead to a bridge failure. Bridge weigh-in-motion (BWIM) system as a high performance and cost-effective technology has been extensively used to monitor vehicle speed and weight on highways. However, the dynamic effect and data noise may have an adverse impact on the bridge responses during and immediately following the vehicles pass the bridge. The fast Fourier transform (FFT) method, which can significantly purify the collected structural responses (dynamic strains) received from sensors or transducers, was used in axle counting, detection, and axle weighing technology in this study. To further improve the accuracy of the BWIM system, the field-calibrated influence lines (ILs) of a continuous multi-girder bridge were regarded as a reference to identify the vehicle weight based on the modified Moses algorithm and the least squares method. experimental results indicated that the signals treated with FFT filter were far better than the original ones, the efficiency and the accuracy of axle detection were significantly improved by introducing the FFT method to the BWIM system. Moreover, the lateral load distribution effect on bridges should be considered by using the calculated average ILs of the specific lane individually for vehicle weight calculation of this lane.

关键词： bridge weigh-in-motion continuous bridge fast Fourier transform influence line axle weight calculation