电力风电行业区域销售总监国电联合动力技术有限公司前程无忧

1、Three elements of cable, truss, and beam-column are implemented in proposed software. ? The proposed software consider both geometric and material nonlinearities. ? It is shown to be an efficient and reliable tool for daily use in design.132 Analysis and design optimization of deep drawing process:

2、Part II: Optimization Original Research ArticleJournal of Materials Processing Technology, Volume 184, Issues 1-3, 12 April , Pages 84-92H. Sattari, R. Sedaghati, R. Ganesan Close preview | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | Reference

3、sReferencesAbstractIn part I of the present work H. Sattari, R. Ganesan, R. Sedaghati, Analysis and design optimization of deep drawing process. Part 1: Three dimensional finite element and sensitivity analysis, J. Mater. Process. Technol., submitted for publication, a finite element formulation bas

4、ed on a combined Total and Updated Lagrangian approach (TUL) has been developed to calculate the sensitivities in the large elasto-plastic strains in sheet metal forming parts obtained by deep drawing. The present part II deals with the use of multiplicative decomposition of the TUL to improve the e

5、fficiency in the analysis and optimum design of blank contours of complicated parts. The TUL exploits the knowledge of the 3D shape of the final workpiece. An iterative scheme is developed to find the original position of each material point in the initial flat blank after which it is possible to es

6、timate the strains and stresses in the final workpiece. The von Mises plasticity is adopted regarding the constitutive equations. In the present work, several developments have been presented: (1) the bending effects are taken into account using shell elements without increasing the number of degree

7、s of freedom per node. (2) Appropriate improvements of resolution algorithms such as the introduction of a relaxation coefficient, a damping factor and a good initial solution are realized. (3) Shape optimization of blank contours is performed using a numerical procedure based on the coupling of the

8、 TUL and the sequential quadratic programming method (SQP). The numerical results obtained using the Lagrangian approaches for the benchmark test are compared with existing experimental and numerical results. The optimization procedure is applied to shape optimization of a square blank which is used

9、 to produce a cup in deep drawing process. The objective function is defined to minimize the thickness variations.Article Outline1. Introduction2. Improvements in resolution algorithms3. Numerical results for forming analysis4. Design optimization5. Sequential quadratic programming method6. Converge

10、nce criterion7. Numerical example of optimization8. Flow chart of algorithm9. ConclusionsReferences Purchase 133 Finite element analysis of tile-reinforced composite structural armor subjected to bending loads Original Research ArticleComposites Part B: Engineering, Volume 35, Issue 1, January , Pag

11、es 57-71S. Mahdi, J. W. Gillespie Close preview | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferencesAbstractComposite structural armor (CSA) is a multi-functional structure that provides ballistic protection, stiffness and streng

12、th at minimum weight. It consists of a multi-layered architecture of polymer composites, rubber and ceramic tiles, stacked in a precise manner to obtain optimal ballistic performance. In the present work, the finite element method is used to conduct a detailed analysis of the mechanisms of load tran

13、sfer and deformation of CSA subjected to bending loads. The results from two modeling approaches (three-dimensional and two-dimensional simulations) are compared to assess the accuracy of the computationally efficient two-dimensional model. The calculated deflections and surfaces strains from both m

14、odels are found to agree very well with experimental results. The stress transfer between the layers is further analyzed using the two-dimensional model and the resulting through-thickness strain and stress distributions are discussed. It is found that the deformation of this multi-layered construct

15、ion is complex and dependent upon the mechanism of stress transfer between the outer surface layer and the ceramic tiles. The effect on non-linear behavior of the constituent materials is investigated. The gap filled with polymer that separates adjacent ceramic tiles is shown to significantly influe

16、nce the stiffness and strength of CSA. It is found that the plastic deformation of the resin corresponds to the onset of non-linear structural response.Article Outline1. Introduction2. Experimental2.1. Materials, fabrication and experimental procedure2.2. Experimental results3. Finite element analys

17、is3.1. Introduction3.2. Three-dimensional finite element model3.3. Two-dimensional finite element model3.4. Modeling data4. Finite elements results4.1. Stiffness prediction4.2. Surface strains predictions4.3. Stress transfer between the cover layer and the ceramic tiles4.4. Through-thickness stress

18、and strain distribution5. Effect of non-linearity (geometric and material) on structural response6. Design issues7. ConclusionsAcknowledgementsReferences Purchase 134 Rate constitutive equations for computational analyses of textile composite reinforcement mechanical behaviour during forming Origina

19、l Research ArticleComposites Part A: Applied Science and Manufacturing, Volume 40, Issue 8, August , Pages 997-1007P. Badel, S. Gauthier, E. Vidal-Sall, P. Boisse Close preview | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferences

20、AbstractTextile composite reinforcements are made up of fibres. Consequently, their mechanical behaviour is a result of the possible sliding and the interactions between the fibres. When they are formed on double curved shapes, these fabrics are submitted to large strains, in particular large in-pla

21、ne shear. Among the mechanical behaviour models for these textile reinforcements, continuous models are most commonly used for forming simulations because they can be used with standard finite elements. The objective of the present paper is to propose a continuous approach for textile reinforcement

22、deformation analysis based on a rate constitutive equation specific to materials made of fibres. The objective derivative of this constitutive model is defined by the fibre rotation. This constitutive model is implemented in ABAQUS and can be used in most commercial F.E. software. The approach is ex

23、tended to materials with two-fibre directions in order to perform simulations of woven fabric forming processes. A set of simulations of large deformations of textile composite reinforcements at the mesoscopic scale (deformation of a woven unit cell) and at the macroscopic scale (deep drawing) is pr

24、esented to show the efficiency of the proposed approach.Article Outline1. Introduction2. Rate constitutive equations3. Textile composite reinforcement mechanical behaviour4. Objective derivative based on the fibre rotation5. Use of GreenNaghdis frame associated to a change of basis6. Numerical simul

25、ations for materials with a single-fibre direction6.1. Elementary tests6.1.1. 45 Simple shear with horizontal fibres6.1.2. Extension followed by a rigid body rotation6.1.3. Extension followed by a 45 simple shear6.1.4. 45 Simple shear with vertical fibres6.2. Mesoscopic simulation of the shear of a

26、2 2 twill unit cell7. Macroscopic simulations of textile reinforcement forming7.1. Approach to textile with two-fibre directions7.2. Fabric forming simulations8. Conclusions and prospectsAcknowledgementsAppendix A. Numerical integration of the rate constitutive equationAppendix B. Objectivity of the

27、 derivative defined from the fibre rotationReferences Purchase 135 New layerwise theories and finite elements for efficient thermal analysis of hybrid structures Original Research ArticleComputers & Structures, Volume 81, Issues 26-27, October , Pages 2525-2538J. Noack, R. Rolfes, J. Tessmer Close p

28、review | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferencesAbstractHybrid structures, for example metallic multiwall thermal protection systems, sandwiches or hot structures, consist of layers with different thermal conductivity.

29、 In addition, radiation and convection can occur within these layers. Analysis of these internal heat transfer mechanisms and the design of hybrid structures require three-dimensional models leading to a high modelling effort. With a new layerwise theory for heat conduction of hybrid structures this

30、 effort can be drastically reduced. Hybrid structures are idealized as structures with homogeneous layers characterised by different thermal conductivities. For layers with internal radiation exchange and convection an equivalent thermal conductivity is assumed.By means of two heat transfer equilibr

31、ium conditions the nodal degrees of freedom become independent of the number of layers. Two four-noded finite shell elements QUADLLT and QUADQLT based on the new theory have been developed. These 2D finite elements enable the calculation of three-dimensional temperature distributions within hybrid s

32、tructures. Comparison with 3D analysis and test results shows good agreement.Article Outline1. Introduction2. New layerwise theories2.1. Linear layerwise theory2.2. Quadratic layerwise theory3. Finite element formulation4. Coupling of elements with different stacking sequence5. Numerical examples6.

33、ConclusionReferences Purchase 136 Automated manufacturing environment to address bulk permeability variations and race tracking in resin transfer molding by redirecting flow with auxiliary gates Original Research ArticleComposites Part A: Applied Science and Manufacturing, Volume 36, Issue 8, August

34、 , Pages 1128-1141Jeffrey M. Lawrence, Peter Fried, Suresh G. Advani Close preview | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferencesAbstractLiquid Composite Molding (LCM) processes inject a resin into a closed mold containing

35、fiber preforms to manufacture a polymeric composite. Many a times, resin does not fully saturate the fiber perform causing one to discard the composite part as scrap. In order to make LCM processes more reliable, a scientific understanding of the resin flow and impregnation into the porous network c

36、ontaining fiber preform can lead to advanced manufacturing techniques which can rely on flow control approaches to improve the yield. The flow is usually controlled by redirecting the resin flow by strategically opening and closing auxiliary injection gates as dictated by the flow monitoring sensor

37、system. There are various approaches to generating such strategies. Once such technique, scenario-based control, has exhibited the potential to compensate for flow disturbances such as race tracking. However, a flexible and reliable manufacturing environment is needed in order to carry out experimen

38、ts in advanced LCM processing. For this, an automated Resin Transfer Molding apparatus was designed and built, containing all of the necessary components. Flow sensors allow for the monitoring of the fluid advancement. Individually controllable injection gates and vents allow for geometrical flexibi

39、lity and flow control. The following study demonstrates usefulness of the manufacturing tool to implement, validate and uncover limitations of a scenario-based flow control approach with geometries of increasing complexity.Article Outline1. Introduction1.1. Liquid composite molding processes1.2. Mod

40、eling and simulation1.3. Disturbances/variations in the process2. RTM workstation2.1. Mold2.2. Flow distribution system2.3. Sensor plate2.4. Controlling computer3. Flow control during filling4. Selected geometries for study4.1. Fender geometry4.2. Engine hood geometry4.3. Windows geometry5. Limitati

41、ons5.1. Mode detection sensitivity5.2. Separation of mode detection and control5.3. Need for parameters6. ConclusionsAcknowledgementsReferences Purchase 137 Computational homogenization analysis in finite elasticity: material and structural instabilities on the micro- and macro-scales of periodic co

42、mposites and their interaction Original Research ArticleComputer Methods in Applied Mechanics and Engineering, Volume 191, Issue 44, 11 October , Pages 4971-5005Christian Miehe, J?rg Schr?der, Martin Becker Close preview | Related articles | Related reference work articles AbstractAbstractNo abstrac

43、t is available for this article. Purchase AbstractThe paper investigates instability phenomena in the context of homogenization-based micro-to-macro transitions of heterogeneous materials at finite strains. This covers structural instability effects (buckling) and material instability effects (local

44、ization) which can occur on both the macro- as well as the micro-scale and may influence each other. We develop a general framework for the theoretical and computational treatment of these instability problems for elastic composites with given periodic fine-scale micro-structures. The key methodolog

45、y is an investigation of the properties and the interaction of two coupled minimization principles which govern a micro-heterogeneous material in the context of a classical homogenization procedure: The principle of minimum potential energy of the macro-structure and the principle of minimum average

46、 energy of the micro-structure. The first variational problem determines the deformation field of the homogenized continuum. The latter yields the fine-scale fluctuation field on a composite micro-structure that is assumed to be attached to each local point of the macro-continuum. Global stability a

47、nd the existence of solutions are based on weak convexity properties of these variational functionals. The convergence of non-convex homogenization functionals is based on the -limit of periodic heterogeneous micro-structures. It defines the relevant micro-structure as an a priori unknown critical e

48、nsemble of periodic cells that catches a possible minimizing buckling mode. We summarize these basic results and recast them in a consistent notation suitable for numerical implementation. Furthermore, we in detail discuss the discretization of the coupled minimization problems by means of finite el

49、ement methods and point out numerical concepts for the detection of material and structural instabilities. The treatment provides a comprehensive guide to the classification and computation of instabilities in micro-heterogeneous solids. Focus is put on the interaction of micro- and macro-instabilit

50、y phenomena such as the loss of macroscopic material stability (localization) induced by a microscopic structural instability (buckling). The performance of the proposed computational methods is demonstrated for representative numerical model problems which treat coupled instability phenomena in mic

51、ro-heterogeneous elastic composites.138 The influence of software developers creative style on their attitudes to and assimilation of a software process innovation Original Research ArticleInformation & Management, Volume 40, Issue 5, May , Pages 443-465Michael J. Gallivan Close preview | Related ar

52、ticles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferencesAbstractThis study examines outcomes associated with differences in software developers creative style, based on Kirtons adaptioninnovation theory. Propositions were developed and tested to

53、 identify the relationship between software developers creativity and their attitude to a technological innovation that altered the software development process in their organizations. Based on adaptioninnovation theory, we expected that innovators (i.e. more innovative employees) would demonstrate

54、higher levels of job satisfaction and performance than adaptors (i.e. less innovative employees), after approximately 4 months of using the innovation. We conducted a survey of 220 developers in two firms that had recently replaced mainframe-based software development with client/server development.

55、 Our results demonstrate a pattern of relationships among employees creative style, attitude to the innovation, job satisfaction, and performance which we believe have important implications for managers responsible for implementing other technological innovations.Article Outline1. Introduction2. Li

56、terature review2.1. Overview of Kirtons adaptioninnovation theory2.2. Research on creativity and information systems3. Research framework and propositions4. Research design and measures4.1. Developing the survey instrument4.2. Measures4.3. Data analysis5. Results5.1. Summary of Proposition 4 results

57、6. Discussion6.1. Summary of findings6.2. Implications for practitioners (IS managers and change managers)6.3. Implications for researchers6.4. Limitations and directions for future researchAcknowledgementsReferencesVitae Purchase 139 A multi-layer triangular membrane finite element for the forming

58、simulation of laminated composites Original Research ArticleComposites Part A: Applied Science and Manufacturing, Volume 40, Issues 6-7, July , Pages 739-753R.H.W. ten Thije, R. Akkerman Close preview | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Table

59、s | ReferencesReferencesAbstractContinuous fibre reinforced thermoplastics offer a cost reduction compared to thermosets due to promising fast production methods like diaphragm forming and rubber pressing. Forming experiments of pre-consolidated four-layer 8H satin weave PPS laminates on a dome geom

60、etry demonstrated that inter-ply friction is a dominant parameter in forming doubly curved components. Therefore, simulations of this process as sequentially draping the individual layers are invalid. A multi-layer triangular membrane finite element has been developed for efficient simulation of lam