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1.
AbstractIndustry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing. 相似文献
2.
实体造型中的几何约束 总被引:5,自引:0,他引:5
实体造型是一个基于约束的过程,完成从功能约束到几何约束、再到代数约束的转化而得到实体模型。本文讨论了几何约束的层次性及其表示,并且对几何约束同设计意图的关系进行了研究,提出了基于CSG/GCG/B-rep的模型表示。 相似文献
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B. P. PEHRSON J. D. LANDES 《Fatigue & Fracture of Engineering Materials & Structures》2007,30(2):73-86
The purpose of this study is to examine the current standard fracture toughness test procedure to determine if there could be an easier method to get a JIc value from the test record. The current method for determining JIc involves a detailed computational and construction procedure. The objective in this study is to simplify the analysis for the determination of JIc. The results of this study show that the load and displacement record for a fracture toughness test can be used to directly estimate a JQ value, a provisional value for fracture toughness, JIc. The J value taken at the maximum load point can be used along with an adjustment factor to estimate a JQ value. This JQ estimate is close to the one obtained from the construction procedure of ASTM Standard E 1820. When a unit‐sized specimen is tested, that is, a specimen with a width of 50 mm and a thickness of 25 mm the maximum load point provides a direct estimate of JQ. Other sizes require a size adjustment factor, which is simply a square root relationship between the width of the test specimen and a unit width. The proposed new method of estimating JQ is simple in concept and requires a minimum number of calculations. It appears to produce values of JQ which are comparable to those obtained from the ASTM E1820 construction procedure and may produce less scatter. 相似文献
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彩色PDP用玻璃基板 总被引:4,自引:0,他引:4
本文讨论了彩色PDP现用钠钙玻璃的热稳定性,指出由于这种玻璃在热处理过程中易变形和收缩,因而不适合作大面积彩色PDP基板材料,介绍了彩色PDP基板玻璃的制造方法和特点。最后介绍了日本旭硝子公司和美国康宁公司各自为彩色PDP新开发的玻璃基板材料PD200和CS25。 相似文献
8.
提出了一种用双边带深侧槽的小尺寸圆形紧凑拉伸试样评定核压力容器(RPV)钢断裂韧性的单试作试验方法,给出了用该方法测定的两个厂家生产的核压力容器用A508CL3钢的断裂韧性参数,还与Charpy试样的试验结果及大尺寸标准试样的试验结果进行了比较。研究结果表明:用双边带深侧槽的小尺寸R-CT试样测得的断裂韧性值比相同恻槽深度预制疲劳裂纹Charpy试样的测试值更接近有效断裂韧性值,所以,用于核压力容器断裂韧性的监测是可行的。 相似文献
9.
S. K. Aslanov 《Combustion, Explosion, and Shock Waves》2006,42(4):450-455
The behavior of the blast wave from an exploding spherical volume is investigated mathematically over the entire range of
blast-wave propagation. The computational method uses analytical results for a similar problem for a point explosion with
counter pressure and the theory of an asymptotically equivalent point explosion. The asymptotic solution of the gas-dynamic
equations away from the explosion site is matched to the initial conditions of blast-wave formation due to the disintegration
of the detonation shock upon its arrival at the boundary of the exploding volume. The spatial distribution of the blast-front
pressure is found for combustible gaseous systems and solid explosives. The theoretical results obtained agree quantitatively
with available experimental measurements.
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Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 4, pp. 93–99, July–August, 2006. 相似文献
10.
U. Reimer
H. -J. Schek
《Data & Knowledge Engineering》1989,4(4):321-352The first part of this paper introduces the basic constructs of a frame representation model and gives a formal definition for them. Subsequently the nested relational model (NF2) is described as an extension of the classical relational model to support relation-valued attributes. In the second part of this paper both models are compared with each other and a mapping of frame representation structures to NF2 structures is specified. The structural similarities between frames and NF2 relations are made clear and it is shown that their main difference is due to the type polymorphism introduced by the concept hierarchy of the frame model. This causes type collisions to occur in the strictly typed NF2 model when frames are directly mapped to NF2 structures. Two solutions to this problem are suggested and compared. The paper concludes with a reformulation of query operations of the frame model in terms of NF2 algebra operations. 相似文献