上海东方体育中心

在上海东方体育中心落成之时,回顾体育中心的设计过程和构思要义,在承袭GMP一贯严谨、理性、简洁的原则基础上,展现灵活、开放、明亮、变化的性格,凸显其独特性。文章就总体设计、单体设计、新技术运用、质量控制等方面详细阐述了项目的设计概念、设计手法、成功和遗憾。     

基于整车刚-柔耦合多体动力学模型的车架动态应力分析

以60 t交流电传动铰接式自卸车车架为研究对象,根据拓扑原理作出整车的结构拓扑图。在此基础上,先建立整车多刚体系统动力学模型,然后建立考虑车架弹性变形的铰接车刚-柔耦合多体动力学模型,并对其进行仿真分析。提取车架关键位置的动态应力-时间历程曲线,验证设计的安全性,并为下一步铰接式自卸车的设计改进和车架的疲劳寿命预测分析提供重要参考依据。     

一种位移放大微动平台的设计和特性分析

为了增大微动平台的工作行程,设计一种新型位移放大机构,并对其静态和动态特性进行分析。采用杠杆原理设计一种新型的二级微位移放大机构。采用有限元软件ANSYS对机构的柔度和放大倍数进行分析,分析结果表明所设计的平台能放大y方向位移,放大倍数为8.81,而在x和z方向位移较小。对机构进行灵敏度分析表明该机构在x、y方向的位移灵敏度分别为0.86μm/μm、8.82μm/μm,说明机构在放大y方向的位移反应较灵敏。对机构进行模态分析,从振型可以看出该机构能实现运动方向为x和y方向平动,但在x方向的位移较小,并且预应力对机构的固有频率影响较小。研究结果表明,所设计的机构具有较大的工作空间和较高的灵敏度。     

Dynamic analysis of bending–torsion coupled composite beams using the Flexibility Influence Function Method

In this work the dynamic behaviour of symmetrical laminated beams was studied, taking into account the effect of bending–torsion coupling by a one-dimensional model. This model includes the influence of the shear force and rotatory inertia. To solve the equations of motion, the Flexibility Influence Function Method (FIFM) was used. The dynamic displacements (deflection, bending rotation, and torsional rotation) were calculated for a beam in which the deflection and torsional rotation were restricted at its both ends, allowing the bending rotation. The accuracy of this method was determined by using a Three-Dimensional Finite Element Method (FEM3D) model to compare the dynamic displacements. The need was shown to incorporate coupling in the one-dimensional model in order to calculate the dynamic deflection and bending rotation of a composite beam.     

Changeability of strategic and tactical production concepts

Changes in the market entail increasing flexibility requirements in product quality and delivery. As a consequence, sales, production, and supplier networks must be able to be adapted quickly. This holds for both physical and organizational structures and processes as well as their IT support (e.g., PPC software). The paper shows what networks, facility layouts, or planning and control systems are more suitable for certain requirements than for others. The differences come to light even within a company, such as when the finished product business shows different characteristics from the semi-finished product business or the spare parts business. In some cases flexibility potentials can be utilized to align resource management to different characteristics. In other cases there still are technical, methodological, and cost constraints.     

Modeling and optimization methods of integrated production planning for steel plate mill with flexible customization

With diversified requirements and varying manufacturing environments, the optimal production planning for a steelmill becomes more flexible and complicated. The flexibility provides operators with auxiliary requirements through an implementable integrated production planning. In this paper, a mixed-integer nonlinear programming (MINLP) model is proposed for the optimal planning that incorporates various manufacturing constraints and flexibility in a steel plate mill. Furthermore, two solution strategies are developed to overcome theweakness in solving the MINLP problem directly. The first one is to transformthe original MINLP formulation to an approximate mixed integer linear programming using a classic linearization method. The second one is to decompose the originalmodel using a branch-and-bound based iterative method. Computational experiments on various instances are presented in terms of the effectiveness and applicability. The result shows that the second method performs better in computational efforts and solution accuracy.     

Flexible and thermally stable SiC fiber mats derived from electrospun boron-doped polyaluminocarbosilane precursors

Polymer-derived SiC fibers are critical structural and functional materials for high-temperature applications, whose service performance can be further improved by introduction of certain heterogeneous elements. Herein, flexible and thermal stable SiC fiber mats were prepared from boron-doped polyaluminocarbosilane (PACS) precursor by electro-spinning, curing and pyrolysis. Two boron-containing compounds o-carborane (oCB) and phenylboronic acid (PBA) were used as the boron sources and their effects on the properties and structure of the SiC fiber mats were investigated. The introduced oCB and PBA had obviously improved the ceramic yield of the cured fiber mats and the flexibility of the SiC fiber mats. However, PBA introduced more boron, but also more oxygen, which leaded to formation of more amorphous SiC_xO_y phases. Although only a small amount of boron was introduced by oCB, a more significant improvement in the thermal stability of the SiC fiber mat was obtained. This work provided a practical approach for fabrication of flexible and thermally stable SiC fiber mats.     

Success of local flexibility market implementation: A review of current projects

The development of distributed energy sources will challenge the management of the electrical system. Local flexibility markets (LFMs) are a promising solution to coordinate the dispatch of distributed energy sources. The LFM development is in its infancy, and numerous challenges should be addressed. This study focuses on four topics for LFM success: the governance model, coordination issues, inc-dec gaming, and competition. Based on a review of current projects, we identify challenges related to the four topics and discuss solutions to overcome these challenges. The proposed solutions are crucial to achieving market efficiency and cannot be considered independently.     

Immobilizing imidazolium ionic liquid in flexible proton exchange membranes to modify microstructure fracture

The imidazolium ionic liquid of (Kevlar/bmimCl/SEBS)₅ membrane was immobilized in flexible proton exchange membranes (PEMs) with the spin coating technology. In the prepared (Kevlar/bmimCl/SEBS)₅ membrane, the imidazolium ionic liquid of 1-butyl-3-methylimidazolium chloride (bmimCl) functioned as glue to modify the microstructure fracture from the stretching operation through occupying the cracks. The proton conduction resistance was reduced with the well-ordered distribution of components in the multilayered microstructure. Although the doped phosphoric acid (PA) molecules charged the proton conductivity, the imidazolium cations of bmim⁺ could participate in the proton conduction through the formation of continuous proton conduction channels. In this research, the folding and stretching operations exerted the negligible effect on microstructure and property of the prepared PEMs. Besides the modification of bmimCl, the deformation of polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SBES) molecular chains and Kevlar nanofibers in the stretching operation contributed to maintain the stable microstructure. The stretching and folding operations led to slight variation on the membrane property. Specifically, the proton conductivities were respectively 3.21 × 10^?2 S/cm and 4.16 × 10^?2 S/cm at 160 °C, which were even superior to 2.77 × 10^?2 S/cm of the pristine membranes. Furthermore, the tensile stress values of the folding and stretching membranes can reach (18.9 ± 1.19) MPa and (32.6 ± 2.63) MPa.