共查询到20条相似文献，搜索用时 703 毫秒
1.
GIS-Based Simulation of Engineering Construction Schedule 总被引：1，自引：0，他引：1
For its complexity, engineering construction schedule design is limited by various factors. Simulation-based engineering construction schedule takes critical path method （ CPM ） network as frame and calls complex cyclic operation network （CYCLONE） simulation model enclosed in advance for its simulation nodes. CYCLONE simulation model takes charge of simulating stochastic duration of activity and efficiency of resources, while CPM model performs project scheduling. This combination avoids the shortcomings of both models. Furthermore. geographic information system （ GIS ） technique is utilized to visualize the construction processes which are otherwise difficult to be understood by static results described. Application in practical project verifies the feasibility and advantage of the technique. 相似文献
2.
George Marx 《International Journal of Science Education》2013,35(1):31-45
The astronomy concepts of 345 young people were studied over a 10‐year period using a multi‐media, multi‐modal methodology in a research design where survey participants were interviewed three times and control subjects were interviewed twice. The purpose of the research was to search for evidence to clarify competing theories on conceptual coherence versus knowledge‐in‐pieces, distinguishing between coherence as revealed in the representational systems at any particular stage in a young person’s development and the changes evident in mental growth thereafter. Thus five research questions concerned with the elements and structure of understanding were investigated: (1) conceptual coherence shown as patterns of high correlation of concept representations between the media used to assess subjects’ understanding within a survey, as well as (2) coherence revealed as consistency of representation of those concepts across media and modalities; (3) enhanced conceptual understanding and skill through repeated interviews across (longitudinal) surveys, as young people develop their knowledge; (4) cultural similarity in subjects’ representations of basic static concepts (e.g. the shape of the Earth); and (5) improved understanding of basic dynamic concepts (e.g. the motion of the Earth) and complex dynamic concepts (e.g. seasons and eclipses), through “knowledge‐skill compounding”. The research findings supported conceptual coherence and rejected the counter argument of knowledge‐in‐pieces (at an alpha level of .05). Further research is recommended to replicate current research in cultures other than those of China and New Zealand studied here to confirm the view that cognition and knowledge are inherently coherent in young people. 相似文献
3.
ZOU Jian-feng ZHENG Yao LIU Ou-zi 《浙江大学学报(A卷英文版)》2007,8(7):1053-1058
Turbulent combustion in a DLR (German Aerospace Center) Scramjet engine was simulated using the newly-proposed Partially Resolved Numerical Simulation (PRNS) procedure. The PRNS procedure uses temporal filtering to define large-scale turbulence, and the model developed to account for unresolved scales is grid independent. No problem about inner commutation error and inconsistencies will arise from the PRNS, while such issues are of concern in traditional Large Eddy Simulation (LES) methods. The mean results have good agreement with the experiment data and the flow structures with small scales are well resolved. 相似文献
4.
Solidworks Simulation软件在产品开发中的应用 总被引：1，自引：0，他引：1
李健 《武汉职业技术学院学报》2012,11(3):84-87
有限元分析（FEA）软件作为CAE软件的主体,目前在工业设计领域已经得到了广泛的应用。对于著名的Solidworks Simulation软件,以一款医疗公司开发的医疗床为实例,分析它在帮助企业缩短产品开发周期,保证产品的可靠性方面大致所进行的工作。 相似文献
5.
In this paper, by teaching a 3D robot unit model and playing back to simulate the assembly process in a virtual assembly environment, errors in robot assembly are analyzed. The paper also presents a visualization method for analyzing accuracy of the robot assembly, and studies the influence of the spatial pose of a robot on the success rate of an axis-hole assembly, and accuracy of the robot teaching program in particular. Through integration of various errors and on the basis of assembly accuracy, tolerance of error sources can be reasonably distributed to meet the assembly accuracy requirement, therefore the planning of robot assembly unit can be improved. 相似文献
6.
SHEN Yu YU Hu-ping RUAN Xue-yu 《浙江大学学报(A卷英文版)》2006,7(8):1343-1350
INTRODUCTION With the continuous development of science and technology, especially the rapid progress of electronic industry and micromachine, microparts are needed more and more, and their technical requirements are higher and higher (Geiger et al., 1994; 1996; Geiger and Engel, 2002). However, traditional processing technologies, like cutting, etc., do not meet these requirements. Traditional plastic forming technology has merits like high production rate, excellent me-chanical proper… 相似文献
7.
Based on the region model of lambda bipolar transistor （ LBT）, a dividing region theory model of PLBT is set up.simulated and verified. Firstly, the principal operations of different kinds of photoelectronic lambda bipolar transistor ,（ PLBT） are characterized by a simple circuit model. Through mathematical analysis of the equivalent circuit, the typical characteristics curve is divided into positive resistance, peak, negative resistance and cutoff regions. Secondly. by analyzing and simulating this model, the ratio of MOSFET width to channel length, threshold voltage and common emitter gain are discovered as the main structure parameters that determine the characteristic curves of PLBT. And peak region width, peak current value, negative resistance value and valley voltage value of PLBT can be changed conveniently according to the actual demands by modifying these parameters. Finally comparisons of the characteristics of the fabricated devices and the simulation results are made, which show that the analytical results are in agreement with the observed devices characteristics. 相似文献
8.
The batch extractive distillation (BED) process has the advantages of both batch and extractive distillation. It is one of the most promising means for the separation of azeotropic and close-boiling point systems. However, so far this process has not been applied in industry due to its over-complexity. A new shortcut model was proposed to simulate the operation of the batch extractive distillation operations. This algorithm is based on the assumption that the batch extractive distillation column can be considered as a continuous extractive distillation column with changing feed at any time. Namely, the whole batch process is simulated as a succession of a finite number of steady states of short duration, in which holdup is considered as constant mole. For each period of time the batch extractive distillation process is solved through the algorithm for continuous extractive distillation. Finally, the practical implementation of the shortcut model is discussed and data from the laboratory and literature are presented. It is found that this model has better adaptability, more satisfactory accuracy and less calculative load than previous rigorous model. Hence the algorithm for simulating BED is verified. 相似文献
9.
Hung-Yuan Wang Henry Been-Lirn Duh Nai Li Tzung-Jin Lin Chin-Chung Tsai 《Journal of Science Education and Technology》2014,23(5):682-691
The purpose of this study is to investigate and compare students’ collaborative inquiry learning behaviors and their behavior patterns in an augmented reality (AR) simulation system and a traditional 2D simulation system. Their inquiry and discussion processes were analyzed by content analysis and lag sequential analysis (LSA). Forty university students were divided into dyads and then randomly assigned into AR group and traditional 2D group to collaboratively conduct an inquiry task about elastic collision. The results of the content analysis and LSA indicated that both systems supported students’ collaborative inquiry learning. Particularly, students showed high frequencies on higher-level inquiry behaviors, such as interpreting experimental data or making conclusions, when using these two simulations. By comparing the behavioral patterns, similarities and differences between the two groups were revealed. The AR simulation engaged the students more thoroughly in the inquiry process. Moreover, students in both groups adopted the same approaches to design experiments. Due to the line of AR research is in its initial stage, suggestions for future studies were proposed. 相似文献
10.
Thebubblecolumnreactor (BCR) ,withbatchfeedandcontinuousgasaerated ,hasobtainedwideapplica tionsinbiochemicalengineering ,chemicalengineeringandwastewatertreatment ,etc .OneimportantfeatureofBCRisthattheconversionandtheyieldofthereactioncanbehighlyincreasedundertheunsteady stateopera tion .Sincethemassandtheheattransferpropertiesinaprocessmainlydependontheflowbehavior ,itisstronglydesirabletoinvestigatetheunsteady stateflowstructurebeforethedesignandscale upofBCRwithhighreactiveconversionsa… 相似文献
11.
HUAN Shi JIANG Guoping Chen Shengming TANG Xiangqian 《天津大学学报(英文版)》2006,12(B09):158-160
The grisliness after-effects can be induced by explosion accident with the collapsing of the structures, the demolishing of the equipments and the casualty of the human beings. Isolation belt constructed between the blast point and the construction is one of the useful design schemes for blast resistance. The nonlinear procedure ANSYS/LSDYNA970 is used to simulate the contact detonation and the isolation belt of blast resistance filled with the air or water respectively. The results indicate that the maximal damage can be caused by the contact detonation, and the isolation belt of blast resistent filled with water can reduce the damage greatly. 相似文献
12.
13.
QIANG Hongfu MENG Lijun 《天津大学学报(英文版)》2006,12(B09):75-78
The normal hypervelocity impact of an Al-thin plate by an Al-sphere was numerically simulated by using the adaptive smoothed particle hydrodynamics （ASPH） method. In this method, the isotropic smoothing algorithm of standard SPH is replaced with anisotropic smoothing involving ellipsoidal kernels whose axes evolve automatically to follow the mean particle spacing as it varies in time, space, and direction around each particle. Using the ASPH, the anisotropic volume changes under strong shock condition are captured more accurately and clearly. The sophisticated features of meshless and Lagrangian nature inherent in the SPH method are kept for treating large deformations, large inhomogeneities and tracing free surfaces in the extremely transient impact process. A two-dimensional ASPH program is coded with C ＋ ＋. The developed hydrocode is examined for example problems of hypervelocity impacts of solid materials. The results obtained from the numerical simulation are compared with available experimental ones. Good agreement is observed. 相似文献
14.
1 .ＩｎｔｒｏｄｕｃｔｉｏｎＧＰＳＳ(ＧｅｎｅｒａｌＰｕｒｐｏｓｅＳｉｍｕｌａｔｉｏｎＳｙｓｔｅｍ)ｉｓａｃｏｎｖｅｎｉｅｎｔａｎｄａｐｐｌｉｃａｂｌｅｓｉｍｕｌａｔｉｏｎｌａｎｇｕａｇｅ ,ｗｈｉｃｈｉｓｅｘｔｅｎｓｉｖｅｌｙｕｓｅｄｉｎｄｉｓｃｒｅｔｅ -ｅｖｅｎｔｓｉｍｕｌａｔｉｏｎｓｔｕｄｉｅｓ .Ｐｒｏｄｕｃｔｉｏｎｓｙｓｔｅｍｓｏｒｐｒｏｄｕｃｔｉｏｎｌｉｎｅｓａｒｅｉｔｓｍａｊｏｒａｐｐｌｉｃａｔｉｏｎａｒｅａｓ .ＵｎｄｅｒｔｈｅｒｅｑｕｅｓｔｓｆｒｏｍｔｈｅＴｉａｎｊｉｎＤｉｅｓｅｌＥｎ… 相似文献
15.
前期已经对某电动汽车进行基于能量利用率的传动比设计,设计出自动变速器传动方案及其尺寸。本文采用Solidworks软件建立箱体结构模型,并以Solidworks Simulation对箱体前盖和后盖分别进行有限元分析,得出最大应力值及出现位置。结果表明,所设计的自动变速器既满足能量利用率最优又符合静强度要求。 相似文献
16.
The grisliness after-effects can be induced by explosion accident with the collapsing of the structures, the demolishing of the equipments and the casualty of the human beings. Isolation belt constructed between the blast point and the construction is one of the useful design schemes for blast resistance. The nonlinear procedure ANSYS/LSDYNA970 is used to simulate the contact detonation and the isolation belt of blast resistance filled with the air or water respectively. The results indicate that the maximal damage can be caused by the contact detonation, and the isolation belt of blast resistent filled with water can reduce the damage greatly. 相似文献
17.
The normal hypervelocity impact of an Al-thin plate by an Al-sphere was numerically simulated by using the adaptive smoothed particle hydrodynamics (ASPH) method. In this method, the isotropic smoothing algorithm of standard SPH is replaced with anisotropic smoothing involving ellipsoidal kernels whose axes evolve automatically to follow the mean particle spacing as it varies in time, space, and direction around each particle. Using the ASPH, the anisotropic volume changes under strong shock condition are captured more accurately and clearly. The sophisticated features of meshless and Lagrangian nature inherent in the SPH method are kept for treating large deformations, large inhomogeneities and tracing free surfaces in the extremely transient impact process. A two-dimensional ASPH program is coded with C . The developed hydrocode is examined for example problems of hypervelocity impacts of solid materials. The results obtained from the numerical simulation are compared with available experimental ones. Good agreement is observed. 相似文献
18.
Simulation of Airblast Load and Its Effect on RC Structures 总被引：1，自引：0，他引：1
In the analysis of a structure subjected to an explosion event, the determination of the blast load constitutes a crucial step. The effect of the blast load on the structure depends not only on the peak shock overpressure, but also the impulse (hence the duration). For structures with a regular geometry, the blast load may be fairly well estimated using appropriate empirical formulae; however, for more complex situations, a direct simulation using appropriate computational techniques is necessary. This paper presents a numerical simulation study on the prediction of the blast load in free air using a hydrocode, with focus on the sensitivity of the simulated blast load to the mesh grid size. The simulation results are compared with empirical predictions. It is found that the simulated blast load is sensitive to the mesh size, especially in the close-in range, and with a practically affordable mesh grid density, the blast load tends to be systematically underestimated. The study is extended to internal blast cases. An example concrete slab under internal explosion is analyzed using a coupled analysis scheme. The internal blast load from the simulation is examined and the response of the RC slab is commented. 相似文献
19.
Three-ring gear reducer , an internal gear planetarytransmission, claims many advantages , including largetransmission ratio, high loading capacity, and compactvolume[1].However ,there still exist some disadvantagesinits application.One is the unbalanced … 相似文献
20.
CRAWFORD John E 《天津大学学报(英文版)》2006,12(Z1)
Cased explosives generate highly energetic fragments as their casing breaks up. Due to the complexity of casing fragment related behavior such as embedment, perforation and ricochet, it may be insufficient to use equivalent triangular pressure loading in fragment impact simulations. This simplified method may over- or under-predict the target response. Recently, a procedure using contact techniques has been proposed to overcome such difficulties. It has been shown that the new method has the inherent capability in modeling the multi-piece and multi-hit fragment impact problems in a more realistic way. To investigate the applicability of the proposed method to simulations involving multi-layer penetration, the selected problems of fragment impact on multi-layer targets are described in this paper. It is demonstrated that this method is capable of predicting the complicated multi-layer structural response caused by fragment impact and penetration. Modeling procedures and some technical issues are also discussed. 相似文献