Contents and Abstracts of Journal of Mechanical Engineering,Vol.46,No.1～4,2010

<正>Structural Design and Hydrodynamics Analysis of a Self-reconfigurable Propeller1 DING Xilun1 WANG Zhengrong1, 2 ZHANG Wuxiang1 (1. Robotics Institute, Beihang University, Beijing 100083, China; 2. Navy Logistic Technology and Equipment Institute of PLA, Beijing 100072, China)     

Development of empirical model for abrasive wear volume of sisal fibre–epoxy composites

Abstract

In this paper, an empirical model was developed for high stress abrasive wear behaviour of unidirectional sisal fibre reinforced epoxy composites under varying operating parameters, for which a number of experiments were carried out to determine the abrasive wear behaviour of the composites. Polysulphide modified epoxy resin was used to make composites having three different sisal fibre concentrations in three different fibre orientations, namely longitudinal, transverse and normal. Abrasive wear of composites depends on operating parameters, such as applied load, grit size, sliding distance and weight percentage of sisal fibre. The abrasive wear data have been analysed using statistical analysis, and empirical relations are proposed.     

Effect of silicon carbide volume fraction on the hot workability of 7075 aluminium-based metal–matrix composites

The hot deformation behaviour and microstructure evolution of stir cast 7075Al alloy and 7075Al alloy with 10, 15 and 20 % volume fraction of 20 μm SiCp composites have been studied by using the processing maps. The compression tests were conducted on both alloys and composites in the temperature range of 300–500 °C and the strain rate range of 0.001–1.0 s^?1 to establish the processing map. The dynamic recrystallization and instability zones were identified and validated through micrographs. The composites showed higher flow stress, efficiency and lower instability regimes than alloy. The 15 % volume fraction of SiCp composites achieved better hot workability due to grain refinement, hardening and strengthening of the material.     

Contents and Abstracts of Chinese Journal of Mechanical Engineering (Chinese Edition),Vol.43,No.1～2,2007

SEVERAL ISSUES OF SCIENTIFIC DEVELOPMENT OF SAFETY PRODUCTION (INCLUDING SAFETY MANUFACTURING) IN CHINA ZHONG Qunpeng ZHANG Zheng YOU Yiliang (School of Materials Science and Engineering, Beihang University, Beijing 100083, China) Abstract: Taking the viewpoint of scientific development on safety produc-     

Effective modulus of Si electrodes considering Li concentration,volume expansion,pore, and Poisson’s ratio of Li-ion batteries

Journal of Mechanical Science and Technology - We propose a novel mathematical model for predicting the effective modulus of Si electrodes in Li-ion batteries by considering the large volume...     

Mechanical and Tribological Properties of Spark Plasma–Sintered Titanium Composites Filled with Different Al-Cr-Fe Quasicrystal Contents

A new type of Ti composite filled with Al-Cr-Fe quasicrystals (QCs) was developed via a spark plasma sintering process. The mechanical and tribological properties of the Ti/QC composites were systematically investigated. It was found that the hardness of the Ti/QC composites significantly increased with increased QC content due to the higher hardness of incorporated QCs than that of the Ti matrix. The tribological results clearly showed that the wear of the Ti/QC composites apparently decreased with increased QC content to 20 wt% as a result of the increased wear resistance of the composites. An excessive loading of 30 wt% QCs resulted in the decreased wear resistance of the Ti/QC composites. It could be concluded that the incorporation of QCs significantly improved the mechanical and tribological properties of the Ti/QC composites with an optimized QC content of 20 wt%.     

Corrosion and tribocorrosion study of 316L steel,Ti–6Al–4V and Ti–10Zr–10Nb–5Ta

ABSTRACT

In this paper, corrosion and tribocorrosion tests have been conducted on three biomaterials: Ti–6Al–4V and 316L steel that are well-known commercial biomaterials and Ti–10Zr–10Nb–5Ta, a new biomaterial elaborated in a levitation-melting furnace. Tests have been conducted in five different electrolytes: NaCl (9g/l), Ringer’s solution, phosphate buffered saline solution (PBS) with and without an addition of bovine serum albumin (BSA). Two amounts of BSA were used: 1 and 5?g/l. In NaCl solution, Ringer’s solution and PBS solution, Ti–10Zr–10Nb–5Ta presents the best corrosion resistance. Conversely, in the presence of proteins, 316L steel shows better resistance to corrosion in comparison with Ti–10Zr–10Nb–5Ta and Ti–6Al–4V. During tribocorrosion tests, the surfaces have been submitted to friction against an alumina ball at open circuit potential (OCP). Measurement of wear rate at the end of the tests indicates clearly that 316L steel shows better resistance to material removal in comparison with Ti–10Zr–10Nb–5Ta and Ti–6Al–4V.     

An experimental study of the hadron calorimeter module response to protons and pions with energies of 1–5 GeV

The design of the hadron calorimeter module is discussed. Such modules are expected to be used in the forward calorimeters of the Multi Purpose Detector (MPD) (Dubna, Russia) and Compressed Barionic Matter (CBM) (Darmstadt, Germany) experiments. The module has transverse dimensions of 20 × 20 cm² and is composed of 60 16-mm-thick lead layers interleaved with 4-mm-thick scintillator plates. Light from scintillator plates is captured by wavelength-shifting optical fibers. The module has longitudinal segmentation and consists of 10 sections. Light collected from each section is read out by micropixel photodiodes with a sensitive area of 3 × 3 mm². Test measurements of the energy resolution and linearity of the calorimeter module response in the hadron momentum range of 2–6 GeV/c have been performed. The longitudinal profiles of the hadron shower, obtained in the measurable energy range both for pion and proton beams, are discussed. The measured energy resolution and the linearity of the calorimeter module response at low energies are presented and compared to the data obtained at high energies.