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也谈轻型钢结构房屋柱基设计 总被引:1,自引:1,他引:0
对柱脚抗剪键的设置和计算中所取用的荷载组合提出个人观点,同时对轻钢结构柱脚螺栓受拉计算提出注意事项. 相似文献
24.
Ed Lowry 《Computer Standards & Interfaces》1991,13(1-3):105-108
Maximizing the satisfaction of a value in an engineering design is usually limited by tradeoffs in which other values become unacceptably sacrificed. In a few cases, however, the maximization is limited by a boundary between what is mathematically possible and what is not. Round wheels, vertical pillars, and binary memory elements are examples of optimum engineering structures which result from such mathematical limits. It is proposed that optimum characteristics of a language data model result similarly by minimizing the variety of primitive data objects, the complexity of those objects, and the number of objects needed to represent data states. Reducing these measures is needed to combine both rich data structure and powerful operations in one language. The minimizations lead to a narrow range of designs for language semantics in which the potential advantages of specialization is small compared with the advantages of commonality. Universal language for support of technical literacy appears to be an appropriate scope of generality in language design. 相似文献
25.
Service Load Effective Compression Flange Width in Fiber Reinforced Polymer Deck Systems Acting Compositely with Steel Stringers 总被引:1,自引:0,他引:1
This paper reports on the field study of a steel stringer-fiber reinforced polymer (FRP) deck composite bridge in Pennsylvania. The objective of the study is to assess the effective compression flange width in the FRP deck and floor systems when they act compositely with underlying steel girders at service conditions. The research results reported herein support the notion of employing a design approach, for both interior and exterior girders of a composite floor system, that is philosophically consistent with current practice related to steel girders acting compositely with concrete decking. It appears from the results presented herein that FRP decks and floors acting compositely with underlying steel girders exhibit an effective width that is close to the actual girder spacing for interior beams, and approximately one-half this value for exterior beams. 相似文献
26.
Design optimization of 3D steel structures: Genetic algorithms vs. classical techniques 总被引:1,自引:0,他引:1
María Belén Prendes Gero Antonio Bello García 《Journal of Constructional Steel Research》2006,62(12):1303-1309
In this paper an elitist genetic algorithm (GA) developed by the authors is compared with common commercial solutions for complex structural optimization. After its prior validation on two-dimensional (2D) structures, the GA was tuned and improved in order to obtain structural elements with minimum weights that satisfy the ultimate limit states of the applicable building code. Subsequently, the same spatial structures were optimized using a commercial structural analysis program. Finally, the cost and weight improvements obtained using the GA, although at a higher computational cost, are discussed. 相似文献
27.
Wolfgang Appelt 《Computer Standards & Interfaces》1988,7(4):377-385
The Office Document Architecture (ODA) is an International Standard which is developed by TC 97/sc 18 of the International Organization for Standardization (ISO) in close collaboration with CCITT's Study Group VIII and with ECMA. This paper describes the current state of a formal specification of the ODA document structures by mathematical means and its use for conformance specification and conformance testing. 相似文献
28.
Yangjun Chen 《Information Processing Letters》2006,99(1):19-26
A precise analysis of the retrieval of signature trees is presented. A signature tree is a data structure constructed over a signature file to speed up searching all those signatures, which match a given query signature. The methods used include a detailed study of probabilistic analysis in conjunction with suitable contour integration of complex variabled functions. 相似文献
29.
Tong Fang Mohsen A. Jafari Stephen C. Danforth Ahmad Safari 《Machine Vision and Applications》2003,15(2):63-75
This paper presents the concept of a process signature for the use of online signature analysis and defect detection in the layered manufacturing (LM) of ceramic sensors and actuators. To achieve the high quality of parts built by the fused deposition of ceramics (FDC), an online process-monitoring system is implemented to detect the processing defects. Using a process signature extracted from the image of a layer captured by the monitoring system, an ideal image is created that is then compared to the original image to detect and identify the defects. Some results of signature analysis and defect detection for single-material and multi-material parts are also presented.Received: 22 July 1999, Accepted: 21 October 2001, Published online: 29 October 2003
Correspondence to: Mohsen A. JafariThis work was supported by the Office of Naval Research under grant # N-0014-96-1-1175. Ref. US Patent # S-5738817, April 14, 1998. 相似文献
30.
Composite films composed of poly(methyl methacrylate‐co‐butyl acrylate) (PMMABA) and nematic‐type liquid crystals E7 and E8 (commercial products from E. Merck, Darmstadt, Germany) were prepared through solvent casting in chloroform. The morphology and electrooptic responses were studied. Scanning electron microscopy observations showed that the liquid‐crystal phase (E7 or E8), as larger, elongated, interconnected cavities, was continuously embedded in a spongelike PMMABA matrix. At a specific level of the liquid‐crystal (E7 or E8) loading (30/70 wt %), the effects of the voltage, temperature, and frequency of an applied alternating‐current electric field on the transmittance of the composite films were measured with a He–Ne laser (wavelength = 632.8 nm). The results were interpreted in terms of the aggregation structure, interfacial interaction, and solubility of the liquid crystal in the matrix polymer. The results indicated that, under these experimental conditions, the output could be controlled to a desired level by the selection of suitable liquid crystals to prepare polymer‐dispersed liquid‐crystal, electrooptic, active composite films with a response time of the order of only milliseconds or less. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献