寒地特等火车站候车室形体尺寸能耗模拟

目的以低能耗建筑设计为目的,对寒地特等火车站候车室形体尺寸及能耗状况展开模拟研究,以实现降低建筑能耗的可持续目标.方法基于数字技术同建筑设计的协同,利用基于Rhino非线性建模平台的Grasshopper参数化设计模组建立试验模型,并利用Grasshopper的插件Honeybee调用EnergyPlus能耗分析软件,通过模拟试验对影响候车室能耗的平面尺寸、长宽比、高度等形体尺寸因素的作用机制展开研究.结果不同影响因素对候车室单位空间能耗影响作用不同;高度对能耗的影响幅度最大,在设计过程中应首先考虑;当候车室平面面积相同,平面长宽比为3∶2时,单位能耗最低;当候车室平面长宽比相同,平面面积为6 000 m2时,单位能耗最低;当候车室平面面积相同,平面长宽比越大,能耗受建筑高度的影响越大.结论通过模拟试验得出了各影响因素同单位建筑能耗间的多元线性回归方程式,可以帮助建筑师们在设计初期计算建筑能耗,从而指导火车站候车室的建筑节能设计.

惯性张量测量研究综述

惯性张量是描述刚体做定点转动时转动惯性的量度,是控制系统设计的关键参数。近年来,飞行器技术的发展使得精确测量大尺寸异形体的惯性张量的需求变得十分迫切。首先,回顾了惯性张量测量的研究历程及当前存在的问题,分别讨论了扭摆法、复摆法、能量法和参数法等方法的测量原理。然后,探讨了这些测量方法在测量大尺寸异形体的惯性张量时需要面对的诸如测量误差的来源和误差补偿等问题。最后,总结了惯性张量测量的发展历程,并指出了目前研究存在的问题和后续的研究方向。

未知环境下基于传感器的移动机器人路径规划

本文提出了基于传感器的移动机器人路径规划方法.该方法改进了Bug算法中的两个前提假设,综合考虑了传感器的数据误差和机器人形体尺寸,规划时只考虑当前状态下所必需的传感数据,不必计算障碍物边线的解析式,节省了存储空间,提高了规划效率,保证了算法的实时性,并对算法的收敛性给予了证明.最后用仿真实验验证了该方法的可行性.

Scale effect mechanism on micro rod upsetting deformation analyzed by crystal plasticity model

To analyze the effect of single grain deformation behaviors on microforming process, a crystal plasticity model was developed considering grains at free surface layer as single grains. Based on the rate-dependent crystal plasticity theory, the analysis of the scale effect mechanism on upsetting deformation of micro rods was performed with respect to specimen dimension, original grain orientation and its distribution. The results show that flow stress decreases significantly with the scaling down of the specimen. The distribution of the grain orientation has an evident effect on flow stress of the micro specimen, and the effect becomes smaller with the progress of plastic deformation. For the anisotropy of single grains, inhomogeneous deformation occurs at the surface layer, which leads to the increase of surface roughness, especially for small specimens. The effect of grain anisotropy on the surface topography can be decreased by the transition grains. The simulation results are validated by upsetting deformation experiments. This indicates that the developed model is suitable for the analysis of microforming processes with characteristics, such as scale dependency, scatter of flow stress and inhomogeneous deformation.

Polycrystalline model for FE-simulation of micro forming processes

A new polycrystal model was presented from the viewpoint of polycrystal structure of the billets considering free surface effects.In the model,the billet was divided into three portions,such as free surface portion,transition portion and internal portion.The grains in free surface portion were considered the single grains,and the anisotropy of the grains was taken into account by introducing grain orientation to explain the inhomogeneous deformation.In the transition portion,the effects of the neighbouring grains were adopted in the model.The grains in the internal portion were considered the polycrystalline material.With the developed model,the upsetting deformation process was simulated by the MSC Superform software.The scatter of the flow stress and inhomogeneous deformation was observed by analysis of the model.The comparisons show that the computational results are good agreed with the experimental results.This means that the presented model is effective.

基于老年生理的电动拐杖椅设计研究

老龄化是全球共同关注的重要问题之一,其必将引发设计理念更新,带来潜力巨大的老年人产品市场。老年人群体特殊的生理特性在设计过程中具有重要指导意义。文章以老年生理的生理力学、关节自由度、形体尺寸为设计依据,将拐杖和座椅两种产品科学性的结合成一种产品,满足老年人行走身体平衡和休息帮扶坐起的需求,具有较好的实用价值和市场推广潜力。

Effects of deformation parameters on formation of pro-eutectoid cementite in hypereutectoid steels

Brittle pro-eutectoid cementite that forms along prior-austenite in hypereutectoid steels is deleterious to mechanical properties. The optimum process parameters which suppress the formation of pro-eutectoid cementite in hypereutectoid steels with carbon content in the range of 0.8%-1.3% in mass fraction, were investigated. Pro-eutectoid cementite formation is effectively hindered by increasing the deformation temperature and decreasing the amount of strain. Transformation at lower temperatures close to the nose of the cooling-transformation diagram also reduces the tendency of the formation of pro-eutectoid cementite. Control of prior-austenite grain size and grain boundary conditions is important. Due to larger number of nucleation sites, finer prior-austenite grain size results in the acceleration of transformation to pro-eutectoid cementite. However, large prior-austenite and straight boundaries lead to less nucleation sites of pro-eutectoid cementite. The cooling rate and carbon content should be reduced as much as possible. The transformation temperature below 660 °C and the strain of 0.5 at deformation temperature of 850 °C are suggested.

Study on Body Form and Garment Size Series of the Middle Age and Aged People

This paper was designed to analyze on the data, which was obtained from 'National Physique Fitness Investigation Report (2000)'. In order to get the typical body form and figure type of the middle age and aged people, it was focused on the body form data of this group (age 40 - 60). After calculation and analyzing, the distinguishing feature of body form and the distribution of figure type were deduced. Finally, the re-classification of body form for Chinese middle age and aged people was suggested. It as also suggested that a new garment size series especially for the middle age and aged should be built to fit for these people. This conclusion would be useful and significant to design and production for clothing company, especially that who take the aged people as their target consumer.

Numerical Analysis of the Influence of Geometry of Ceramic Units （Blocks） on Structural Walls

This paper presents finite element results of ceramic masonry prisms and walls under concentric compression. Four different hole geometries of ceramic units were studied （called Types A, B, C and D）. The A-type unit had two rectangular hollows, B-type and C-type units have two rounded hollows and different net areas, mad the D-type unit had two rectangular hollows and a double central web. This study analyzed units, prisms and structural walls joined by bedding mortar. The objective was to verify the stress distribution in units and mortars. The results showed that the distribution of compressive stress along the length and width of those units was uniform, but lateral tensile stress along the length was distinct for different geometries. In addition, this study observed that hollow shapes have an important influence in stress distribution. The D-type unit was the one that showed more uniform tension distribution, without peaks of stress concentration. This indicates that a D-type unit is the most efficient unit for use in masonry structures.