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Geng P.,Beihang University | Xing J.Z.,Tianjin Polytechnic University | Chen X.X.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology
Archive of Applied Mechanics | Year: 2016

The maximum strength ratio and more uniform strength for all layers can be achieved by variation of winding angle of filament-wound (FW) vessel. The deformation and stresses of a thick-walled cylinder with multi-angle winding filament under uniform internal pressure are proposed. The stresses of each orthotropic unit of fiber layers, as well as longitudinal stress along the fiber direction, transverse stresses perpendicular to the fiber direction and shear stress in the fiber layer are derived analytically. An optimization model of FW closed ends vessel under uniform internal pressure subjected to Tsai–Wu failure criterion to maximize the lowest strength ratio through thickness with optimal variation of winding angle is built. Two optimization methods are adopted to find the optimized winding angle sequence through different ways, and their combination led to more efficient algorithm is suggested. The research shows that the material utilization and working pressure can be increased by proper winding angle variation, and several optimization winding angle sequence schemes are found for different thickness ratios cylindrical vessels with two typical composite materials E-glass/epoxy and T300/934, which are useful for many applications of FW vessel design and manufacture. © 2016 Springer-Verlag Berlin Heidelberg


Sun R.-L.,Tianjin Polytechnic University | Sun R.-L.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Niu W.,Tianjin Polytechnic University | Lei Y.-W.,Tianjin Polytechnic University | Tang Y.,Tianjin Polytechnic University
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2014

Laser cladding was carried out on the surface of TC4 titanium alloy by Nd: YAG laser using Ni60+Ni/MoS2 powder mixture as cladding material. The microstructure of the coating was examined by XRD, EDS, SEM and OM. Microhardness and tribological properties of the coating were measured. The results show that MoS2 decomposes during laser cladding process. The selective chemical reaction between S and Cr occurs and non-stoichiometric CrxSy forms. TiC phase forms due to the fact that C reacts with Ti. C and Ti come from the Ni60 alloy and substrate, respectively. The nearly spherical CrxSy particle and dendritic TiC uniformly distribute in the cladding coating. Due to the reinforcement of TiC and anti-friction of CrxSy, laser cladding coating not only has high wear resistance, but also has a low and smooth friction coefficient.


Liu D.-H.,Tianjin Polytechnic University | Xing J.-Z.,Tianjin Polytechnic University | Xing J.-Z.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Chen X.-X.,Tianjin Polytechnic University
Jisuanji Jicheng Zhizao Xitong/Computer Integrated Manufacturing Systems, CIMS | Year: 2015

Aiming at the different neutral curves in cross sections perpendicular to the axis made by the taper deformation under flexspline of harmonic drive produced by cam wave generator, a spatial tooth profile of circular spline was designed to improve meshing performance. The spatial tooth profile was constructed with a series plane tooth profiles in the cross sections by spatial deformation of flexspline. A design method for spatial tooth profile of circular spline which spatial engaged with deformed flexspline and a calculation method of backlash between engaged teeth surface were established. Based on the conjugated tooth profiles in planes, the spatial tooth profile was generated by using lofting algorithm, and the interference and backlash results were checked. The research found that the spatial tooth profile could increase the meshing domains and contact area. There was a little difference between the loft method of two sections with straight guide line and a series section loft spatial tooth profiles, which could meet the design requirement of normal precision of harmonic transmission device. ©, 2015, CIMS. All right reserved.


Xing J.,Tianjin Polytechnic University | Geng P.,Tianjin Polytechnic University | Yang T.,Tianjin Polytechnic University | Yang T.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology
Composite Structures | Year: 2015

Multiple winding angle filament-wound (FW) structures may lead to more uniform strength for all filament layers, while there is no analysis method for deformation and stresses calculation of FW cylinder with variation wound angle. Deformation and stresses of a thick cylinder with multi-angle winding hybrid filament under axial loading and internal and external pressure were investigated. The deformation and stresses of each orthotropic unit of fiber layers, as well as longitudinal stress along the fiber direction, transverse stresses perpendicular to the fiber direction and shear stress in fiber layer were obtained analytically. The degenerated case of the model includes single winding angle FW cylinder, FW vessel with a liner, and sandwich pipe with one or multiple core layers. Numeric results of finite element models are present, which are very close to the theoretical results. The research shows that material utilization and working pressure can be increased by multi-angle FW procedure. © 2015 Elsevier Ltd.


Lei Y.-W.,Tianjin Polytechnic University | Lei Y.-W.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Wu E.-X.,Central South University
Cailiao Kexue yu Gongyi/Material Science and Technology | Year: 2010

In order to inhibit the grain growth of WC during the sintering process and obtain ultrafine WC-12Co alloys with high strength and hardness, the influence of VC/Cr3C2 inhibitors and sintering temperature on the microstructure and mechanical properties of ultrafine WC-12Co was investigated using JSM-5600LV scanning electron microscope, LJ-3000 stretcher and Rockwell HR-150 sclerometer. The mechanism of grain growth inhibition was also analyzed. The results show that alloys with homogeneous microstructure and excellent properties are obtained when the optimal proportion of additions is added. Sintered at 1450 °C, the transverse rupture strength and hardness reach 3710 MPa and 91.5 HRA for the ultrafine WC-12Co alloy with 0.2%VC/0.5% Cr3C2 (wt%). The mechanism of VC/Cr3C2 inhibitors is that the reaction between WC and VC leads to the presence of small (V, W)C precipitates on WC/Co interfaces, which decreases the interfacial energy; on the other hand, Cr3C2 mainly dissolved in the binder phase reduces the solubility of WC in the binder phase. The driving force for WC grain growth from reprecipitation process is decreased and WC grain growth is retarded.


Lei Y.,Tianjin Polytechnic University | Lei Y.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Sun R.,Tianjin Polytechnic University | Tang Y.,Tianjin Polytechnic University | Niu W.,Tianjin Polytechnic University
Optics and Laser Technology | Year: 2012

A three dimensional model was proposed to simulate high power laser clad TiC/NiCrBSiC composite coatings on Ti6Al4V alloys. The temperature distribution, temperature curves on different nodes, three dimensional shape and size of TiC melting region, molten pool and heat affected zone (HAZ) of the substrate were obtained. To have a clear physical insight into the phase transformation and microstructure evolution in the coatings during laser cladding process, a theoretical kinetic analysis was performed to elucidate the nucleation, growth velocity, and size of TiC particles on the basis of simulated temperature curves of the molten pool. A good quality TiC/NiCrBSiC composite coating with low dilution rate and excellent metallurgical bond was fabricated under optimal processing parameters using powder mixture of TiC and NiCrBSiC as clad material and cuboid of Ti6Al4V alloys as substrate. To validate the reliability of the proposed model, the theoretical results were compared with the microstructure of the coatings. It shows that these theoretical results are in excellent agreement with the experiment cases. © 2011 Elsevier Ltd. All rights reserved.


Sun R.-L.,Tianjin Polytechnic University | Sun R.-L.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Niu W.,Tianjin Polytechnic University | Lei Y.-W.,Tianjin Polytechnic University | Tang Y.,Tianjin Polytechnic University
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2012

Ni based composite layer reinforced by in situ synthesized TiB 2 and TiC on Ti-6Al-4V alloy substrate was prepared by laser cladding.The friction and wear properties in vacuum (10-5 Pa) of the laser clad layer were investigated on a YTI TB-100 wear tester. The worn surfaces of wear couple were observed by scanning electron microscope (SEM) and optical microscope (OM), and the wear mechanisms were discussed. The results show that the friction coefficient of the laser clad layer is 0.25-0.5, obviously lower than that of Ti-6Al-4V alloy, which is 0.45-0.8, and the worn volume of the laser clad layer is 40% as that of Ti-6Al-4V alloy. The worn volume increases with increasing of sliding velocity and normal load. The wear mechanism of the laser clad layer in vacuum is adhesion wear and abrasion wear due to adhesive material transferring.


Chang B.,Tianjin Polytechnic University | Jin G.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Wang Y.,Tianjin Polytechnic University
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

A spherical metamorphic mechanism with parallel structure was proposed. It consisted of a moving platform, a base plate and four connecting legs between moving platform and base plate. Three of these legs had the same structure named circle legs and the other one named middle leg. Spherical metamorphic mechanism could transform to normal configuration and metamorphic configuration respectively with the change of constraint applied by middle leg. The moving platform was in possession of three revolute degrees of freedom which equivalent to spherical joint and extra translational freedom in the direction of radius. Based on screw theory, the mobility of this mechanism was analyzed firstly. Secondly, the constraint sub-matrix and actuation sub-matrix were obtained and the complete Jacobian matrix was established by integrating these two sub-matrices. In the end, the singular conditions of spherical metamorphic mechanism were analyzed by investigating the ranks of the complete Jacobian matrix and methods used to avoid the occurrence of singularities were given which were propitious to mechanical design.


Xu Y.,Tianjin Polytechnic University | Xu Y.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Wang Z.,Tianjin Polytechnic University | Wang Z.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | And 2 more authors.
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2011

To extract the dynamic response characteristics of blades from the vibration response of whole turbine set efficiently, then take it as the characteristic parameters of blade working states and achieve fault detection and diagnosis of the wind turbine blades, a finite element method is used to build a dynamic model for 300 W wind turbine. Natural frequency and vibration mode of whole set can be obtained and compared to validate the rationality of the model by modal analysis. Vibration acceleration response signal under normal working state and eccentricity fault state can be detected by the hammering method. The length fractal dimension which is taken as the index of diagnosing the eccentricity fault of blades can be calculated using the theory of length fractal dimension in nonlinear vibration system. The result shows that the method is effective to distinguish the normal state and the eccentricity fault state, and detect the eccentricity position and the value of wind turbine blades.


Sun R.,Tianjin Polytechnic University | Sun R.,Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology | Niu W.,Tianjin Polytechnic University | Lei Y.,Tianjin Polytechnic University | Tang Y.,Tianjin Polytechnic University
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2013

CrxSy/Ni coating is prepared on H13 steel by laser cladding using powder mixture of NiCrBSi+33%Ni/MoS2 (mass fraction). The microstructure of the coating is examined using optical microscope (OM), scanning electronic microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffractor (XRD). The frictional wear properties of the coating are tested. The results show that the coating consists of CrxSy particles distribute in γ-Ni dentrites and γ-Ni+MoNi4 eutectics matrix. The in situ formed CrxSy particles appear quasi-spherical shape, with size of 5~20 m. The relatively larger particles are mainly distributed in the upper layer of the coating and the smaller particles are mainly distributed in the middle and bottom layer of the coating. Due to the lubrication of CrxSy, the friction coefficient of the situ formed CrxSy/Ni self-lubricating coating is significantly lower than that of laser clad NiCrBSi coating. However, its wear resistance slightly decreases.

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