不确定视角下产品结构性能优化设计综述与展望

目的复杂产品在工程装备、航空航天等我国优先发展的战略领域中扮演着不可替代的重要角色,在其结构设计过程中普遍存在着各种不确定性,导致产品结构性能很难实现最优,甚至出现重大故障。方法针对复杂产品设计过程中的多粒度模糊不确定、随机不确定、不完备区间不确定和高维混合不确定等特点,将不确定性理论与产品结构设计过程相结合,系统地构建了不确定视角下产品结构性能优化设计理论体系,提出了多粒度模糊不确定下产品质量特性精准提取、随机不确定下产品功能结构模块化求解、不完备区间不确定下产品结构方案多属性决策、高维混合不确定下产品关键结构可靠性优化等关键技术,并指出了产品结构性能优化设计的未来发展方向。结论此设计理论能够充分适应和利用产品设计过程的多种不确定信息,为在结构设计环节切实提升产品性能提供了有力参考。

建筑结构耐久性与施工工艺的关联性研究

建筑结构的耐久性是关系到建筑寿命和安全性能的重要因素,同时,施工工艺对建筑结构的耐久性有着重要影响。在本研究中,我们系统地研究了施工工艺对建筑结构耐久性的影响,并提出一些改进建筑耐久性的策略。首先,我们对现有的建筑物进行了结构性能和施工工艺的详细分析,发现施工工艺对建筑结构性能有着直接的影响。特别是混凝土浇筑工艺和钢结构焊接工艺对建筑的结构耐久性产生了显著影响。通过改进这两种工艺,使建筑的结构性能明显提高。其次,我们根据施工环境的实际情况,提出了一种综合施工工艺和建筑材料选择的优化策略,通过实施这种策略,大大提高了建筑的结构耐久性。在此基础上,我们还进一步研究了施工工艺对其他因素,如耐火性、抗震性等的影响,进一步证实了施工工艺的关键作用。本研究的结果不仅能为提高建筑结构的耐用性提供理论指导,也为现场施工提供了实际的操作建议。

金属磷化物在电解水制氢中的应用研究进展

电解水被认为是目前最有前途的制氢方法之一。基于商用贵金属基催化剂成本高和储量有限的情况,开发低成本、高性能的电催化剂是实现电解水制氢产业化的关键。过渡金属磷化物因具有独特的物化性质和高催化活性而被广泛关注,但导电性和活性位点密度的不足限制了其在工业化制氢中的应用。首先阐述电解水析氢的机理及过渡金属磷化物的重要作用。然后从单金属磷化物、双金属磷化物、改性金属磷化物和结构调控过渡金属磷化物4个方面分析不同种类的过渡金属磷化物以及提升其催化性能的途径,并比较了当前过渡金属磷化物的常用制备方法。最后总结提升催化性能的主要策略,展望过渡金属磷化物未来的机遇和挑战。期望本综述有助于过渡金属磷化物电催化剂的设计开发与应用。

装配式建筑结构设计关键点技术分析

在装配式建筑结构的设计中,装配式建筑结构与常规的结构设计有较大的区别。在工程实施过程中,要充分重视装配式建筑结构设计要点,并达到相应的规范要求,有效提高工程的设计效率,降低工程返工,从而提高工程的整体效益。所以,在设计装配式建筑时要充分考虑其合理性。

从连续到离散 关于2018威尼斯建筑双年展中国馆“云市”的建造实验

文章梳理了机器人空间打印工艺的前期实验室研究脉络,通过对2018年威尼斯建筑双年展中国馆室外展亭"云市"进行"实验室研究-数字设计-数字建造"的全流程详细介绍,从建造方式和材料两方面详细探究了机器人数字建造为未来乡村建造带来的新的可能性。

碳基固体氧化物燃料电池理论模拟概述

主要对碳基固体氧化物燃料电池(SOFC)中三传二反的控制方程、不同尺度的不同物理场理论模型以及碳基燃料的重整、催化和硫化等方面进行概括总结。SOFC有可使用氢气、一氧化碳、甲烷和其他的碳氢化合物作为燃料进行电化学反应的燃料灵活性,但使用碳氢燃料需要解决诸如碳基燃料的重整、电极的催化、积碳和硫化等问题。电池内部反应气体的物质输运、电荷输运、能量输运、动量输运和化学及电化学反应状态均可以用偏微分方程来描述。运用这些电化学反应和输运的偏微分方程,结合材料的微观性质,可以建立SOFC的多尺度多物理场模型。通过理论模型研究材料微结构与性质、工作条件、几何构型等参数对电池性能的影响,对SOFC材料组成与电池堆结构进行定量分析和优化设计,可以加速SOFC技术的更快发展。

Contrastive analysis and crashworthiness optimization of two composite thin-walled structures

For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF.

Performance-based passive control analysis of adjacent structures:Optimization of Maxwell dampers

The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements of the Maxwell dampers are proposed based on the optimal target of making the total exceeding probability of the adjacent structures to be minimal.The applicability of the analytical expressions of the Maxwell damper damping parameters under different seismic performance targets are firstly examined and then the preferable damping parameters of the Maxwell dampers are proposed through the extensive parametric studies.Furthermore,the optimal arranging positions and optimal arranging numbers of the Maxwell dampers between the adjacent buildings are derived based on a large number of seismic fragility analyses,as well.The general arranging laws of the Maxwell dampers between the adjacent buildings are generated based on the discussion of the theoretical method through the simplified plane model.The optimal parameters and optimal arrangement of the Maxwell dampers presented make both the adjacent structures have preferable controlled effects under each seismic performance target which can satisfy the requirements of multi-performance seismic resistance of the modern seismic codes.

Optimized body structure and packaging for car ODB impact performance

Front bumper, crash box and side rail are key body structural parts in front crash. Deformation space is affected by compartment packaging. The improvement suggestions are proposed to solve the problems existed in the current vehicle struc- ture and compartment packaging based on the areas that influence performance of automobile offset deformable barrier impact, such as the side rail, mounting, storage battery packaging,etc. It is proved that dO % offset crash simulation result of one certain car is well-correlated with the physical test. Optimization cases meet the crash performance requirements. The objec- tive of the analysis is to guide structural design and improves a car＇ s crash safety performance.

Performance improvement of car body structure in 100% frontal impact

During the 100%front impact,all the parts of front car will participate in the course;the crash stiffness of bodywork will also reach the peak.During the crash,rational structure of bodywork can resist the distortion,absorb more energy and get better mode of distortion and low deceleration rate,so as to meet the performance of crash safety.The paper mainly makes optimization analysis based on the problems of front side rails,subframe,firewall,and optimization cases are confirmed which can decrease the intrusion and deceleration rate of the whole car.The structure of bodywork after optimization can meet the performance of crash safety.

Multi-criteria assessment of offshore wind turbine support structures based on dynamic property optimization

Increasing size of wind turbine and deep water deployment have raised the issue of appropriate selection of the most suitable support structure to make offshore wind energy cost competitive.The paper presents an optimization methodology for decision making process of bottom mounted supports of offshore wind turbines （OWTs） through reasonable engineering attributes derivation.Mathematic models of support structures are reduced by the generalized single-degree-of-freedom theory with relatively fewer structural parameters.Soft-stiff design optimization based on dynamic properties of OWTs is performed for monopile and lattice supports with different wind turbines,water depth and hub height.Attributes of support structures,wind turbines and environment conditions are applied in the multi-criteria decision making method——TOPSIS for benchmarking of those options.The results illustrate the effectiveness of the proposed optimazation methodology combined with economical and environmental attributes together.

基于CAE的汽车保险杠研究与改进

相比于传统吸能盒而言,由于其由单一属性的材料构成,所以其吸收能量的范围较小,存在两个极端,即溃缩,或者不溃缩。当汽车在中低速行驶发生碰撞时,由于碰撞的应力小于材料的屈服极限,所以此时碰撞的属性为刚性碰撞,以至于不能有效保护驾乘人员的安全。本文基于材料力学及有限元思想,借助计算机进行CAE分析,成功设计出一款符合材料力学的两个叠加且吸能效果较好、碰撞应力范围广的吸能盒。通过对不同材料性能的研究,数据结果表明一个铝合金材料和一个普通碳素钢Q235材料的四方形吸能盒通过激光搭接焊[1]的方式叠加的吸能效果最好,并保证汽车在中低速碰撞时,吸能盒能够有效地发生溃缩以最大程度保护驾乘人员安全。

Bidirectional Clone Node Model of Optimizing Performance of Structured P2P Overlay Network

In order to reduce the maintenance cost of structured Peer-to-Peer (P2P),Clone Node Protocol (CNP) based on user behavior is proposed.CNP considers the regularity of user behavior and uses the method of clone node.A Bidirectional Clone Node Chord model (BCNChord) based on CNP protocol is designed and realized.In BCNChord,Anticlockwise Searching Algorithm,Difference Push Synchronize Algorithm and Optimal Maintenance Algorithm are put forward to increase the performances.In experiments,according to the frequency of nodes,the maintenance cost of BCNChord can be 3.5%～32.5% lower than that of Chord.In the network of 212 nodes,the logic path hop is steady at 6,which is much more prior to 12 of Chord and 10 of CNChord.Theoretical analysis and experimental results show that BCNChord can effectively reduce the maintenance cost of its structure and simultaneously improve the query efficiency up to (1/4)O(logN).BCNChord is more suitable for highly dynamic environment and higher real-time system.

Optimization of compound gear pump

This paper introduces the performances of compound gear pump. Based on the target of having the smallest mass per unit volume, the paper established a mathematical model of optimization, and obtained the results of optimization of the pump.

System analysis and path choice for modern agricultural development:a case study of Suzhou

From the view of system theory, modern agriculture in a region embodies elements conformity, structure optimization, multi-functionality and sustainable development. This paper first expounds on the relationship among agricultural elements, structure, function and development theoretically, compartmentalizes agriculture types based on human-land elements matching, and depicts the development path of agricultural multi-functionality. it shows that the matching of human-land elements is a key to agricultural types, and the multi-functionality is an indication of agricultural development stages. At last, as a case study of Suzhou in eastern coastal area, the paper analyzes the evolvement situation and developing mechanism and some typical models of modern agriculture which suit to agriculture system evolvement. The results .show that in Suzhou the agriculture productivity, has improved greatly; And along with the agriculture structure optimizing, agriculture function has translated from ＂production ＂ to ＂non- production and production ＂. With simulation of agricultural trend in Suzhou, it is .found that Suzhou has a LP- dependence （labor productivity） on agricultural element, so Suzhou will has much more potential in land productivity. Based on the above analysis on agricultural system, some typical patterns on modern agriculture in Suzhou are brought up, such as export-oriented agriculture, enterprises-leading agriculture, science and technology, parks agriculture, stereoseopic agriculture, and tourism and sightseeing agriculture.

Unraveling the roles of mesoporous TiO2 framework in CH3NH3PbI3 perovskite solar cells

Both of planar and mesoporous architectures prevail for perovskite solar cells(PSCs).However,it is still an open question how the architecture affects the performance of PSCs.The inconsistent results in the references often create confusion.In particular,the specific roles of mesoporous frameworks are yet to be well elaborated and require further clarification.In this study,we carefully compared the properties of perovskite films and the device performances for both architectures to unravel the roles of mesoporous TiO2 framworks in CH3NH3PbI3 PSCs.The detailed characterizations of structural,microscopic,optical and electrical properties revealed that the presence of mesoporous TiO2 framework contributed to enlarged perovskite crystal sizes,enhanced light harvesting,efficient electron extration and suppressed charge recombination.As a result,compared with the planar device,the mesoporous device yielded an improved power conversion efficiency of 18.18%,coupled with a reduced hystersis.This study reveals the benefits of mesoporous TiO2 framework in PSCs and provides the guidance for the design and optimization of architectures for high-performance devices.