This paper introduces several types of multi-engine multi-gearbox marine gearing. A total of two dynamic modeling methods are proposed to predict the coupled vibration of these systems. The dynamic models of four engines with two shafts under different working conditions are established, and the effects of coupling, speed, configuration and power loss on the system vibration are studied.
This paper proposes a novel geometrical approach to compliant mechanism synthesis based on similarity transformation of pole maps. The study demonstrates the feasibility of applying the geometric similarity transformation to the compliant mechanism and then proposes the procedure of synthesis method. In addition, this work illustrates the synthesis method with two examples.
A nonlinear dynamic model of the noncircular face gear (NFG) was established. A semi-analytical approach, based on HBM and discrete Fourier transformation, is utilized to obtain the periodic responses. The results show that an increase in the eccentric ratio, input velocity and error amplitude will cause the non-rattle, unilateral rattle and bilateral rattle state in succession, and a jump phenomenon will appear when the state of the gears is transformed from unilateral to bilateral rattle.
We discuss a systematic electric vehicle design process. The steering geometry of the vehicle is analyzed, and the turning angle and radius are designed. The displacement of the vehicle under a load is calculated by rigidity analysis. The experimental modal analysis of the real frame and the finite element method are verified for the body-in-white manufacturing process. No-fuse switches and fuses are used to provide overcurrent protection. A solid-state relay is used for current protection.
In industrial production, the reducer often determines the accuracy of the machine. Designing a reducer with high strength and good accuracy plays an important role in industrial development. In this paper, combined with previous studies, a new type of reducer based on the lever structure is designed, and the performance of the reducer is optimized. Finally, the most appropriate geometric parameters are obtained to ensure the high efficiency of the reducer. It is effective and stable.
1. A new type of MRE torsional vibration absorber (TVA) is devised. The modal analysis, the frequency tracking scheme, and the damping effect are intensely studied. 2. A transient dynamic simulation is carried out to validate the rationality of the machine structure. The magnetic circuit simulation analysis and the magnetic field supply analysis are performed to substantiate the intellectual of the TVA. 3. A special test rig is built to assess the frequency shift characteristics of the TVA.
In this article, the lightweight design of a palletizing manipulator arm structure is carried out. The optimization target is designed in 3D with Solid Works. To determine the optimization area and the secondary reconstruction model after the structure is optimized, the reliability and cost of the design structure are also considered. The meta-software performs mechanical performance simulation experiments under the corresponding working conditions for the lightweight structural design.
This paper presents the design of a dynamometer, with a one-spoked wheel elastic component, to measure the drilling thrust force and drilling moment. After manufacturing, a calibration operation is conducted, and tests are performed by measuring the drilling forces, thrust, and torque on American Iron and Steel Institute (AISI) 1020 steel. Tool wear is studied, and the results are presented in the paper. Obtained results demonstrate the efficiency and accuracy of this measuring instrument.
Robots are a hot topic of research nowadays. Making robot action more accurate and faster is the direction of scholars' efforts. Based on the hydraulic quadruped robot designed by the State Key Laboratory of Fluid Power & Mechatronic System, Zhejiang University, this article discusses the lightweight design for manifold mounted on the hydraulic actuator. Through topology optimization and channel optimization, the part is lighter and the drag loss is less.
According to the structural characteristics of the blisk, a new adaptive belt tool system for the blisk finishing is developed. Due to the strong nonlinearity of the pneumatic system, a two-dimensional fuzzy PID controller is developed for the pneumatic force control. Finally, the experiments show that the polishing process is very stable and the roughness after polishing is less than 0.4 μm, which proves the effectiveness of the proposed new belt tool system and the fuzzy PID controller.
This article examines the historical development of ancient water-powered mechanical clocks. The study begins with a comprehensive analysis and comparison of the different types of ancient clepsydra, their use and development, development of their feedback systems, power systems, and time-reporting systems.
This paper describes a dynamic mathematical model of a new type of two-stage nutation drive system with double circular-arc bevel gears. The dynamic displacement-vibration coupling model takes into account the gyro torque and side clearance of the nutating gear. A numerical analysis geometric model of the nutation drive system is developed. The geometric model considers the time-varying and contact deformation of nutation gear meshing.
Liquid-metal direct writing is a cost-effective and green technology, which is very promising for the customized fabrication of flexible circuits and functional devices. The smooth flowing and conveying of liquid-metal ink are still huge challenges that need significant attention. In this paper, the force mechanism of liquid-metal ink transported by ball rotation and translation of the printing head was analyzed. The flexible complex circuit and functional electronic pattern were printed.
In order to improve modification effectiveness, a novel UV-assisted chemical modification (UVA-CM) strategy is proposed based on UV photocatalytic theory, which contributes to developing a novel hybrid chemo-mechanical process monocrystalline silicon. A series of comparative experiments was performed to evaluate modification effectiveness among different strategies. The results show that the liquid–solid chemical modification effect is obviously enhanced through UV advanced oxidation reactions.
In this paper, a lined pipe was formed through a drawing process. In double-layered pipes, shear strength is the most important design factor. We verified the effect on shear strength by changing the pipe surface roughness. In order to apply the surface roughness in FEM analysis, the surface roughness was converted to the friction coefficient. Through FEM analysis, we obtained a critical value for the change in shear strength.
The temperature distribution of a machine tool spindle is affected by its air gap. The more serious the air gap eccentricity is, the more uneven the temperature field of the spindle is. In the process of machine tool processing, the instability of the spindle temperature field leads to the decline of parts processing quality and unqualified products, which not only wastes materials, but also affects the processing process.
A program is designed for the myoelectric hand with two control pathways, one for the thumb (controlled utilizing medial nerves) and the second for the rest of the fingers (controlled by the side nerves). The robotic hand was first printed with the use of a 3D printer.
Non-circular grinding is used in the grinding of crankshafts. In this study, an equation for detecting the angle error in non-circular grinding is established. Previous studies did not exclusively detect the errors caused by bending deformation and torsional deformation. However, the established equation detects these errors separately. The angle error was found to be up to 0.44 arcsec, which is 5 % of the angle error obtained from previous studies.
The paper proposed a normal contact stiffness model considering 3D topography and elastic–plastic contact of rough surfaces. The proposed model is validated using experimental tests conducted on two types of specimens and is compared with published theoretical models. The proposed model can provide a tool for efficient calculation of the contact force, deformation, and contact stiffness in engineering surfaces.
This study carries out the complex eigenvalue analysis of influence factors of rail corrugation by using the three-dimensional finite-element model of a wheel–rail system based on the theory of friction self-excited vibration. The results show that improving the vertical and lateral stiffnesses of fasteners, controlling the wheel–rail friction coefficient below 0.4, and maintaining balanced superelevation can effectively reduce the occurrence possibility of rail corrugation.
In this paper, an effective UKF-based estimation method is proposed to accurately estimate the driving states of vehicles. First, a three degrees of freedom (3-DOFs) vehicle dynamics model is established, and then a vehicle driving state estimation method is designed based on the UKF algorithm. Finally, by using CarSim and MATLAB/Simulink software, the co-simulation and validation are carried out to validate the accuracy of the proposed method under the sinusoidal and fishhook conditions.