检索结果-南通市图书馆

HEAT TREATMENT STRENGTHENING EFFECTS OF RARE EARTHS ON Mg-9Al ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 8-14页

作者： Y.S.Wang J.Z.Yu Q.D.Wang W.J.Ding shanghai co.mopolitan Automobile Accessory co. LTD Shanghai 200083 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200030 China

Mg-9Al-xRE magnesium alloys were studied, where, x is 0, 0.4. 0.8. 1.2 and 1.6% (in weight percent, wt%), respectively. Influence of rare earths (RE) on micro structure. and strength in both T4 (solute heat treatment) and T6 (solute heat treatment and artificial ageing treatment) were investigated. Strength of specimen was tested at ambient temperature. The micro structure was analyzed by optical microsco.y, scanning electron microsco.y (SEM) and X-ray diffraction analysis. RE additions improved T4 tensile strength of the treated alloys. Small addition (0.4wt%) of RE greatly improved the strength of ageing treated (T6) Mg-9Al alloy, but further additions caused decreasing.

关键词： Mg-Al alloy rare earth (RE) heat treatment mechanical property strength

co.pyrolysis characteristics of typical co.ponents of waste plastics in a falling film pyrolysis reactor

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第10期26卷 2176-2184页

作者： Zechen Jin Lijie Yin Dezhen Chen Yuanjie Jia Jun Yuan Yuyan Hu Thermal and Environmental Engineering Institute Tongji University Shanghai 200092 China shanghai Municipal Engineering Design Institute (Group) co. Ltd. Shanghai 200092 China

Waste plastics mainly co.e from MSW and usually exist in the form of mixed plastics. During the co.pyrolysis process of mixed plastics, various plastic co.ponents have different physico.hemical properties and reaction mechanisms. co.sidering the high visco.ity and low thermal co.ductivity of molten plastics, a falling film pyrolysis reactor was selected to explore the rapid co.pyrolysis process of typical plastic co.ponents(PP, PE and PS).The oil and gas yields and the co.positions of pyrolysis products of the three co.ponents under different ratios at pyrolysis temperatures were analyzed to explore the co.pyrolysis characteristics of PP, PE, and PS. The study is of great significance to the recycling of waste plastics.

关键词： co.pyrolysis Falling film reactor Waste plastics

Biomechanical Study on the Novel Biomimetic Hemi-Pelvis Prosthesis

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2013年第4期10卷 506-513页

作者： Zikai Hua Yongwei Fan Qinghong Cao Xianbo Wu Departrment of Mechatronics Engineering and Automation Shanghai University Shanghai 200072 P. R. China shanghai Thytec co. Ltd Shanghai 201112 P. R. China

A pelvic endoprosthesis is the primary means of pelvic reco.struction after internal hemipelvectomy. In this study, a novel biomimetic hemipelvic prosthesis, including an artificial ilium, an artificial acetabulum, and an artificial pubis, was developed. A Finite Element Method （FEM） was carried out to investigate the biomechanical performance of a pelvis reco.structed with biomimetic hemipelvic prosthesis. Two models, including the reco.structed pelvis and the original pelvis （co.trol model）, were established acco.ding to the geometry from CT data of a human male patient with pelvic bone sarco.as. The FE models predict that the biomeehanical function of the pelvic ring can be reestablished using this prosthesis. Results show that the body force loaded on the S 1 vertebra is restored and transferred towards the sacro-iliac joint, and along the ilium onto the bearing surface of the artificial ilium, then to the artificial acetabulum and pubis. Von Mises stresses observed in this reco.structed pelvis model are still within a low and elastic range below the yielding strength of co.tical bone and Ti6A14V. The values of deformation and strain of the reco.structed pelvis are close to the data obtained in the original pelvis. With the partial replacement of the pubis, little influence is found towards the pubis symphysis. However, the interface between the prosthesis and pelvic bone may beco.e the critical part of the reco.structed pelvis due to the disco.tinuity in the material properties, which results in stress shielding and deformation co.straining. So a biomimetic flexible co.nection or inter layer to release the deformation of pelvis is suggested in future designing.

关键词： biomimetic prosthesis pelvic reco.struction biomechanics FEM

Tensile deformation behavior of co.rse-grained Ti-55 titanium alloy with different hydrogen additions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2021年第8期40卷 2092-2098页

作者： Xi-Feng Li Fang-Fei Xu Lan Hu Fu-Hui Zhu Jun Chen Department of Plasticity Technology School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200030China shanghai Aerospace Equipments Manufacturer co. Ltd.Shanghai200245China

The effect of hydrogen addition on the deformation behavior of co.rse-grained Ti-55 alloys(~20μm)was studied by uniaxial tension tests at high *** elongation of hydrogenated Ti-55 titanium alloy firstly increases and then decreases with hydrogen co.tent increasing at 8750 *** highest elongation of 243.8%is obtained in the hydrogenated alloy with 0.1 wt%H,and the peak stress reaches a minimum value of 29.0 MPa in the hydrogenated alloy with 0.3 wt%*** with that of the unhydrogenated alloy,the elongation of the hydrogenated alloy with 0.1 wt%H increases by 41.3%and its peak stress decreases by 40.6%at 875℃.Hydrogen addition can promote the transformation of β phase and the dislocation *** hydrogen co.tent can evidently improve the deformation properties of co.rse-grained Ti-55 titanium alloy.

关键词： co.rse-grained Ti-55 titanium alloy Hydrogen addition Plastic deformation

3D fracture modelling and limit state analysis of prestressed co.posite co.crete pipes

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第1期13卷 165-175页

作者： Pengfei HE Yang SHEN Yun GU Pangyong SHEN School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China shanghai SMI Engineering Project Management co. Ltd.Shanghai 201103China

In this manuscript,we study fracture of prestressed cylindrical co.crete *** co.crete pipes play a major role in tunneling and underground *** structure is modelled fully in 3D using three-dimensional co.tinuum elements for the co.crete structure which beam elements are employed to model the *** allows the method to capture important phenomena co.pared to a pure shell model of co.crete.A co.tinuous approach to fracture is chosen when co.crete is subjected to co.pressive loading while a co.bined co.tinuous-discrete fracture method is employed in *** model is validated through co.parisons with experimental data.

关键词： cylindrical co.crete structures limit state analysis 3D fracture modelling prestressed co.posite pipes reinforced co.crete three-point bending test

Research on wind-induced responses of a large-scale membrane structure

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第2期12卷 297-305页

作者： Zhou Xuanyi Han Zhihui Gu Ming Zhang An-an Zhang Weiyu Fang Wei State key Laboratory of Disaster Reduction in Civil Engineering Tongji University shanghai Institute of Meteorological Science shanghai World Expo Land Holding co. Ltd East China Architectural Design and Research Institute co. Ltd

The wind-induced responses of a large-scale membrane structure, Expo Boulevard, are evaluated in this study. To obtain the wind pressure distribution on the roof surface, a wind tunnel test is performed. A brief analysis of wind pressure on the membrane roof is co.ducted first and then an analysis of the wind-induced responses of the structure is carried out using a numerical integral method in the time domain. In the process of calculation, the geometrical nonlinearity is taken into acco.nt. Results indicate that mean, RSM and peak values of the structure responses increase nonlinearly while the approaching flow velocity increases. Strong nonlinear characteristics are observed in the displacement responses, whereas the responses of nodal stress and cable axial force show minimal nonlinear properties when the membrane structure is subjected to wind loads. Different values of the damping ratio only have a minimal impact on the RSM response of the structure because the background co.ponent is a dominant part of the total dynamic response and the resonant co.ponent is too small. As the damping ratio increases from 0.02 to 0.05, the RMS responses of vertical displacement, nodal stress and cable axial force decrease by 8.1%, 6.7% and 17.9%, respectively. Since the mean co.ponent plays a significant role in the wind-induced response, the values of the gust response factor are not high for Expo Boulevard.

关键词： wind tunnel test wind-induced response time domain method geometrical nonlinear analysis

APPLICATION OF TIME-VARYING VISco.S GROUT IN GRAVEL-FOUNDATION ANTI-SEEPAGE TREATMENT

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第3期23卷 391-397页

作者： CHENG Peng-da LI Lu TANG Ju WANG Dao-zeng shanghai Institute of Applied Mathematics and Mechanics Shanghai university Shanghai 200072 China Beijing Wangleihong Foundation Project co. Ltd Beijing 100071 China shanghai Institute of Applied Mathematics and Mechanics Shanghai university Shanghai 200072 China

The time-varying visco.ity of co.mon grout and the co.trollable grout are measured with a rotation visco.eter in experiments. The time-varying visco.ity of grout is analyzed acco.ding to the characteristics in the process of anti-seepage treatment for gravel foundation. The principle of effective stress for porous medium is applied to analyzes the fluid-structure co.pling in grouting. In the co.sideration of co.pling physical variables, dynamic models of porosity, permeability and visco.ity are co.structed. The diffusion radius can thus be defined by the foundational porosity. The distribution of holes in field experiments is designed acco.ding to the diffusion radius of grout. Then, the permeability test is designed to verify the grout effect. The calculated diffusion radius co.ncides with experimental results, and the permeability meets the requirements of the project, which is valuable for the anti-seepage treatment in gravel foundation.

关键词： fluid-structure co.pling visco.ity gravel foundation

Performance Improvement of a Centrifugal co.pressor for the Fuel Cell Vehicle by Tip Leakage Vortex co.trol

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2021年第6期30卷 2099-2111页

作者： CHEN Haoxiang ZHUGE Weilin ZHANG Yangjun MA Xuelong TAO Lin State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China Weichai Power co. Ltd.Weifang 261061China Xecaturbo(shanghai)Technology co. Ltd.Shanghai 200241China

Heightened interests have been laid at the preliminary design and optimization of the centrifugal co.pressor for the fuel cell *** centrifugal co.pressor for fuel cell vehicle is driven by a high-speed motor;however,the limit of the motor speed makes the flow passage of the impeller long and narrow,which leads to a serious tip leakage *** tip leakage loss deteriorates the co.pressor *** this paper,3-D numerical simulations were carried out with the aim of investigating the tip leakage loss in a prototype centrifugal co.pressor for a 100 kW fuel cell *** results revealed that the mixing loss caused by the interaction between the tip leakage vortex and the downstream tip leakage flow co.tributed to the major part of the tip leakage *** path of the tip leakage vortex almost followed the streamwise direction,while the downstream tip leakage flow exhibited strong circumferential momentum,which referred to the fact that they were nearly ***,a flow co.trol approach,which was realized by enhancing the blade loading around the leading edge of blade tips in this paper,was proposed to decrease the interaction angle between the tip leakage vortex and the downstream tip leakage flow and then mitigate mixing loss by changing the flow direction of the tip leakage *** results showed a smaller interaction angle was achieved in the optimized impeller co.pared with the baseline ***,the efficiency was also improved by 1.30%at design co.dition and the maximum efficiency improvement co.ld be up to 10%at large mass flow co.dition of 92000 r/*** manufactured and tested,the optimized co.pressor was proved to achieve an isentropic efficiency of 75.84%at design co.dition.

关键词： centrifugal co.pressor fuel cell vehicle efficiency improvement tip leakage vortex mixing loss

Improvement of the co.pressive Strength of Carbon Fiber/Epoxy co.posites via Microwave Curing

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2016年第3期32卷 226-232页

作者： Xuehong Xu Xiaoqun Wang Qun Cai Xu Wang Ran Wei Shanyi Du School of Materials Science and Engineering Beihang University shanghai Aircraft Manufacturing co. Ltd.

Microwave processing was used to cure the carbon fiber/epoxy co.posites and designed for improving the co.pressive strength of the materials. By co.trolling the power of microwave heating, vacuum bagged laminates were fabricated under one atmosphere pressure without arcing. The physical and mechanical properties of co.posites produced through vacuum bagging using microwave and thermal curing were co.pared and the multistep （2-step or 3-step） microwave curing process for improved co.pressive properties was established. The results indicated that microwave cured samples had somewhat differentiated molecular structure and showed slightly higher glass transition temperature. The 2-step process was found to be more co.ducive to the enhancement of the co.pressive strength than the 3-step process. A 39% cure cycle time reduction and a 22% co.pressive strength increment were achieved for the co.posites manufactured with microwave radiation. The improvement in specific co.pressive strength was attributed to better interracial bonding between resin matrix and the fibers, which was also demonstrated via scanning electron microsco.y analysis.

关键词： Carbon fiber Epoxy Microwave curing co.pressive properties