High Performance Structures and Materials Engineering

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Authors: Long Bin Liu, Dong Xu Liu, Ming Yun Lv
Abstract: Inflatable structures have many potential applications in space collapsible structures, this paper based on the premise of the same exploring features on the Planetary Exploration Device (PED) designs a new type of inflatable and lightweight model of PED. The device structure is designed to be a wheel style, which can be folded together in the transport process and in non-working state. Comparing with traditional devices, the new Wheeled Planetary Exploration Device (CWPED) reduces the space of transporting the exploration equipments and decreases the transport costs, moreover, this device provides convenient conditions for the equipment package of the CWPED, and there are evident advantages in the aspects of handing, solar absorption, volume and quality. This article mainly introduces the preliminary design of the CWPED, and the structural characteristics of the device, the principle of motion control and the design of wheeled body skin material are analyzed.
Authors: Lin Xin Tong, Jin Hong Li, Jian Cao
Abstract: A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The powers were characterized by differential thermal analysis (DSC-TG) and X-ray powder diffraction (XRD). Phase separation was promoted by doping both TiO2 and Fe2O3; with increasing the amount of dopant ions the formation temperature of Si-Al spinel decreased and the formation temperature of mullite increased by TiO2 doping but decreased by Fe2O3 doping. The formation temperature of pure mullite was about 1250-1350 °C.
Authors: Lin Xin Tong, Jin Hong Li, Jian Cao
Abstract: . A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The received powers with highest amount of TiO2 and Fe2O3 additive in range of 3.7-5.6 % and 12.5-15.9 % respectively as starting materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopies (SEM) and energy dispersive spectrometry(EDX). Fe3+ and Ti4+ cation has been incorprated into the crystal lattice of mullite unevenly. The overall trend of Ti, Fe-doped mullite powers with additive amount changing is Δa>Δb>Δc(Except sample 5.6Ti-1350 is Δb>Δa>Δc owing to its excess amount of TiO2), and the relative change of Ti, Fe-doped mullite powers is Δc(%)>Δb(%)>Δa(%)(Except sample 5.6Ti-1350 and 15.9Fe-1350 is Δb(%)>Δc(%)>Δa(%) with the maximum amount of dopant ions).
Authors: Liang Fan, Lei Zhang, Fu Hai Li
Abstract: Introduction on superiority of high performance concrete (HPC), then present and compare five methods of HPC mix design in detail. Both fixed grout volume method and cement coefficient method are concentrating on the research of cementing materials. Infilled coefficient method and mix design method based on the best paste-aggregate ratio obtain the optimized sand ratio in the best voidless condition. Overall calculation method is based on the volume model, elicits formula of sand ratio and water consumption and ends the method of looking up the table for sand ratio and water content. Through the comparison of methods, we find that it's a trend that HPC mix design method can develop from semi-quantitative to quantitative, from experience to science.
Authors: Shao Peng Wu, Jun Han, Xing Liu
Abstract: Bitumen is widely used in road construction. Due to heavy traffic loads and environmental factors, bitumen properties will change during service life. Bitumen will age due to diffusion of oxygen and UV radiation. Repeated loading will result in decreasing strength because of fatigue. In this paper, one layer clay powder was used to modify base bitumen with different mass contents. Then the influences of ultraviolet radiation (UV) aging on the dynamic fatigue properties of the layered clay powder were evaluated by Dynamic Shear Rheomoter (DSR) and Universal Testing Machine (UTM). The ageing evaluation shows that the ageing resistance of bitumen is improved and this improvement is more notable in bitumen fatigue than mixture.
Authors: Bin Yang, Qin Shou Huang, Xin Wang Qiu, Hua Xu
Abstract: Partial wheel loading of the existing old cement concrete pavement joint will easily causes shear-type reflective cracking of asphalt overlay, which will cut down the service life of the pavement. This paper conducts an research on the changing rules of stress intensity factors of reflective cracking in asphalt overlay suffer dynamic loads. Choose 3 asphalt overlays with typical reflective cracking extend length of 1cm, 4cm and 8cm to investigate the impacts of parametric variation of vehicle speed, asphalt overlays thickness and modulus and stress absorbing layer on stress intensity factors of reflective cracking in asphalt overlays suffer singe-wheel dynamic loads. Results show that time history curves of dynamic stress intensity factors declines with the increase of structure-layer parameters; the maximum amplitude decreases as time goes on; the larger the structure parameter is, the faster the degradation is; and the vibration levels to gentle in the later half period, but stress intensity factors are not equal to zero in the last period of vibration, which shows that there exists residual stress intensity factors.
Authors: Wei Guo Li, Ru Zhuan Wang, Ding Yu Li, Dai Ning Fang
Abstract: In this paper, based on the study of effects of various physical mechanisms on the fracture strength of porous ceramic materials, a thermo-damage strength theoretical model applied to each stage of temperature is established. Using the model, the sensitivities of fracture strength to relevant parameters and their variation with temperature are studied in detail. The results show that under low temperature the strength is sensitive to the changes of porosity, pore size and pore shape factor, while under high temperature the effects of porosity, pore size and pore shape factor on the strength compared to the temperature are negligible, yet the strength is very sensitive to the Young’s modulus, thus the Young’s modulus is the dominant of strength under high temperature. This study will provide a theoretical basis and guidance to the design and application of porous ceramic materials.
Authors: Yang Kuan Liu, Tao Cai, Shi Guang Ju
Abstract: In machinery and equipment manufacturing industry, screw is an important part. Not only as a precision screw precision transmission components, but also commonly used for precision measuring devices. Precision screw itself directly affects the accuracy of precision machine tools and precision measuring instruments for transmission, positioning precision and accuracy, and thus the processing and inspection of precision screw is higher demanded. Traditionally, screw inspection is usually done by manual and the quality of inspection is not high, with very low inspection efficiency. To solve these problems, optimized system for screw inspection was designed and implemented. Using the Quartile range method in Statistics to remove outliers, and with the help of kalman filter, systemic error is got rid of. With these methods, raw measurement data is analyzed and processed, and inspection report is generated. The efficiency of screw inspection is highly improved.
Authors: Zhi Wei Wang, Lei Shi, Peng Li, Wei Cao
Abstract: For an actual project of groundwater source heat pump air conditioning system in Yangli region, by the field investigation on energy usage status of the system operation, analyzes the causes of non-energy-saving operation such as water pumps energy consumption too much, presents an intelligent control strategy of the system energy saving operation for solving the problem, performs the program design of energy saving control based on Programmable Logic Controller (PLC) and variable frequency technique, finally predicts the system energy saving potential.
Authors: Zhi Wei Wang, Ji Feng Zhao, Zhi Jie Gao
Abstract: For the different hot water supply system plans of residential buildings, this paper established multi-objective factors fuzzy matrix based on fuzzy set concept, proposed a new dynamic preference function for fuzzy comprehensive assessments, using two kinds of methods i.e., the Weighted Relative Deviation Distance Minimum (WRDDM) method and the Quantitative Index Comprehensive Decision Making(QICDM) method, the optimal plan can be chosen. Due to the time and space consideration of the new preference function, the fuzzy comprehensive evaluation (FCE) method can be used for the multi-objective optimization of hot water supply system plans of residential buildings in different regions and different periods.

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