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Abstract In this article, a 300-ton truck crane was used as the research object, and the data and experience of telescopic boom design were integrated to optimize the design research under three dangerous working conditions of the telescopic boom. Three-dimensional (3D) modeling software and finite element software were used to model and statistically analyze the truck crane telescopic boom. Then the correctness of the finite element model was verified by static experiments, and the design was optimized. Under the condition of satisfying the strength and stiffness, the telescopic crane boom was optimized by using the response surface optimization module in Ansys workbench software to be lightweight, and more satisfactory results were obtained. Finally, through the modal and flexural analysis of the optimized model, ideas and suggestions were provided for the further optimization of the telescopic boom.

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Abstract Due to their high strength and good flexibility, wire ropes are widely used in various intense applications. A wire rope will present complex wave mechanics, especially under impact conditions. In this article, wire ropes (steel core rope and hemp core rope alternately twisted) were used to study the wave dynamic response of steel wire ropes with preload shock. The transmission law of wire rope shock waves was obtained through actual measurements. The results showed that the compression wave and shear wave were generated and propagated along the rope after impact. The conduction of shear waves had significant reflection characteristics, and the reflected waves overlapped with each other. The conduction velocity of the impact shear wave of the steel core wire rope increased with increasing pretension. The peak tension caused by impact decayed exponentially.

Abstract The optimal negative stiffness structures and the hydraulic mounts used to replace the driver’s seat traditional suspension system and cab’s traditional rubber mounts of the soil compactors are proposed to enhance the driver’s ride quality and control the cab shaking. A nonlinear dynamic model with 7 degrees of freedom of the vehicle is established to analyze the ride quality under various operating conditions of the vehicle moving and working on off-road terrains. The root mean square values of the driver’s seat displacement, driver’s seat acceleration, and cab pitch’s acceleration are chosen as the objective functions. The investigation results show that both the optimal negative stiffness structures and the hydraulic mounts used on the driver’s seat suspension and cab isolation system greatly improve the driver’s ride quality and control the cab shaking under all the different operating conditions of the vehicle.

Abstract In order to meet upcoming emission targets, an increasing number of ships using Liquefied Natural Gas (LNG) as fuel have been put into service. In this context, many shipowners are particularly interested in the dual-fuel (DF) large-engine technology, which enables ships to operate with both gaseous and conventional liquid fuels. The use of different combustion principles in DF engines requires a layout of the base engine with a relatively low compression ratio (CR) for the gas mode to prevent unstable combustion (knocking). However, this layout leads to disadvantages in the Diesel operation mode, which requires a higher CR for optimal fuel efficiency. Therefore, a two-stage variable compression ratio (VCR) system is a technology particularly suitable for DF engines. It allows to reduce fuel costs by approximately 5.5%.

Abstract A novel modeling method for the hydraulic hub motor drive system (HHMDS) is proposed to overcome the difficulty of using the complex AMESim model in the hardware-in-the-loop (HIL) test. The hydraulic pipeline model of the HHMDS is simplified by the lumped parameter approach. According to the node cavity method, a set of flow pressure differential equations is derived. These equations are used to describe the dynamic model of the HHMDS. To solve the rigidity problem of the model and improve the real-time performance of simulation, the HHMDS model is simplified with the integrated model and order reduction methods. Then, the simplified model is created through MATLAB/Simulink, and the accuracy of the modeling method is verified. In the three typical operating modes of the heavy commercial vehicle with HHMDS, the simulation results of the Simulink model and AMESim model are basically the same. At last, the model established by the Simulink is used in the HIL test.

Abstract This article proposes a novel approach to reduce the destabilizing impacts of the shifted loads of heavy trucks (due to improper loading or liquid slosh) by pneumatic suspension design. In this regard, the pneumatically balanced suspension with dual leveling valves is introduced, and its potential for the improvement of the body imbalance due to the shifted load is determined. The analysis is based on a multi-domain model that couples the suspension fluid dynamics, shifted-load impacts, and tractor-semitrailer dynamics. Truck dynamics is simulated using TruckSim, which is integrated with the pneumatic suspension model developed in AMESim. This yields a reasonable prediction of the effect of the suspension airflow dynamics on vehicle dynamics. Moreover, the ability of the pneumatic suspension to counteract the effects of two general shifted loads - static (rigid cargo) and dynamic (liquid) - is studied.

Abstract Electric heavy-duty tractor-trailers (EHDTT) offer an important option to reduce greenhouse gases (GHG) for the transportation sector. However, to increase the range of the EHDTT, this effort investigates critical vehicle design features that demonstrate a gain in overall freight efficiency of the vehicle. Specifically, factors affecting aerodynamics, rolling resistance, and gross vehicle weight are essential to arrive at practical input parameters for a comprehensive numerical model of the EHDTT, developed by the authors in a subsequent paper. For example, drag reduction devices like skirts, deturbulators, vortex generators, covers, and other commercially available apparatuses result in an aggregated coefficient of drag of 0.367. Furthermore, a mixed utilization of single-wide tires and dual tires allows for an optimized trade-off between low rolling resistance tires, traction, and durability.

Abstract Recently, electric heavy-duty tractor-trailers (EHDTTs) have assumed significance as they present an immediate solution to decarbonize the transportation sector. Hence, to illustrate the economic viability of electrifying the freight industry, a detailed numerical model to estimate the battery capacity for an EHDTT is proposed for a route between Washington, DC, to Knoxville, TN. This model incorporates the effects of the terrain, climate, vehicular forces, auxiliary loads, and payload in order to select the appropriate motor and optimize the battery capacity. Additionally, current and near-future battery chemistries are simulated in the model. Along with equations describing vehicular forces based on Newton’s second law of motion, the model utilizes the Hausmann and Depcik correlation to estimate the losses caused by the capacity offset of the batteries. Here, a Newton-Raphson iterative scheme determines the minimum battery capacity for the required state of charge.

Abstract In this article, a unique design for Hydro-Pneumatic Energy Harvesting Suspension HPEHS system is introduced. The design includes a hydraulic rectifier to maintain one-way flow direction in order to obtain maximum power generation from the vertical oscillation of the suspension system and achieve handling and comfort car drive. A mathematical model is presented to study the system dynamics and non-linear effects for HPEHS system. A simulation model is created by using Advanced Modeling Environment Simulations software (AMEsim) to analyze system performance. Furthermore, a co-simulation platform model is developed using Matlab-Simulink and AMEsim to optimize the PID controller parameters of the external variable load resistor applied on the generator by using Particle Swarm Optimization (PSO).