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Static Analysis (static + analysis)
Kinds of Static Analysis Selected AbstractsIdentification of Modal Combinations for Nonlinear Static Analysis of Building StructuresCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2004Sashi K. Kunnath An increasingly popular analytical method to establish these demand values is a "pushover" analysis in which a model of the building structure is subjected to an invariant distribution of lateral forces. Although such an approach takes into consideration the redistribution of forces following yielding of sections, it does not incorporate the effects of varying dynamic characteristics during the inelastic response. Simple modal combination schemes are investigated in this article to indirectly account for higher mode effects. Because the modes that contribute to deformations may be different from the modes that contribute to forces, it is necessary to identify unique modal combinations that provide reliable estimates of both force and deformation demands. The proposed procedure is applied to typical moment frame buildings to assess the effectiveness of the methodology. It is shown that the envelope of demands obtained from a series of nonlinear static analysis using the proposed modal-combination-based lateral load patterns results in better estimation of inter-story drift, a critical parameter in seismic evaluation and design. [source] Discrete singular convolution methodology for free vibration and stability analyses of arbitrary straight-sided quadrilateral platesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008Ömer Civalek Abstract A new discrete singular convolution (DSC) method is developed for vibration, buckling and static analyses of arbitrary straight-sided quadrilateral plates. The straight-sided quadrilateral domain is mapped into a square domain in the computational space using a four-node element. By using the geometric transformation, the governing equations and boundary conditions of the plate are transformed from the physical domain into a square computational domain. Numerical examples illustrating the accuracy and convergence of the DSC method for straight-sided quadrilateral thin plates such as rectangular, skew, trapezoidal and rhombic plates are presented. The results obtained by the DSC method were compared with those obtained by the other numerical and analytical methods. Copyright © 2007 John Wiley & Sons, Ltd. [source] Optimal solid shell element for large deformable composite structures with piezoelectric layers and active vibration controlINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2005X. G. Tan Abstract In this paper, we present an optimal low-order accurate piezoelectric solid-shell element formulation to model active composite shell structures that can undergo large deformation and large overall motion. This element has only displacement and electric degrees of freedom (dofs), with no rotational dofs, and an optimal number of enhancing assumed strain (EAS) parameters to pass the patch tests (both membrane and out-of-plane bending). The combination of the present optimal piezoelectric solid-shell element and the optimal solid-shell element previously developed allows for efficient and accurate analyses of large deformable composite multilayer shell structures with piezoelectric layers. To make the 3-D analysis of active composite shells containing discrete piezoelectric sensors and actuators even more efficient, the composite solid-shell element is further developed here. Based on the mixed Fraeijs de Veubeke,Hu,Washizu (FHW) variational principle, the in-plane and out-of-plane bending behaviours are improved via a new and efficient enhancement of the strain tensor. Shear-locking and curvature thickness locking are resolved effectively by using the assumed natural strain (ANS) method. We also present an optimal-control design for vibration suppression of a large deformable structure based on the general finite element approach. The linear-quadratic regulator control scheme with output feedback is used as a control law on the basis of the state space model of the system. Numerical examples involving static analyses and dynamic analyses of active shell structures having a large range of element aspect ratios are presented. Active vibration control of a composite multilayer shell with distributed piezoelectric sensors and actuators is performed to test the present element and the control design procedure. Copyright © 2005 John Wiley & Sons, Ltd. [source] Priority research areas for ecosystem services in a changing worldJOURNAL OF APPLIED ECOLOGY, Issue 6 2009Emily Nicholson Summary 1.,Ecosystem services are the benefits humans obtain from ecosystems. The importance of research into ecosystem services has been widely recognized, and rapid progress is being made. However, the prevailing approach to quantifying ecosystem services is still based on static analyses and single services, ignoring system dynamics, uncertainty and feedbacks. This is not only partly due to a lack of mechanistic understanding of processes and a dearth of empirical data, but also due to a failure to engage fully with the interdisciplinarity of the problem. 2.,We argue that there is a tendency to ignore the feedbacks between and within both social and ecological systems, and a lack of explicit consideration of uncertainty. Metrics need to be developed that can predict thresholds, which requires strong linkages to underlying processes, while the development of policy for management of ecosystem services needs to be based on a broader understanding of value and drivers of human well-being. 3.,We highlight the complexities, gaps in current knowledge and research, and the potentially promising avenues for future investigation in four priority research areas: agendas, processes, metrics and uncertainty. 4.,Synthesis and applications. The research interest in the field of ecosystem services is rapidly expanding, and can contribute significantly to the sustainable management of natural resources. However, a narrow disciplinary approach, or an approach which does not consider feedbacks within and between ecological and social systems, has the potential to produce dangerously misleading policy recommendations. In contrast, if we explicitly acknowledge and address uncertainties and complexities in the provision of ecosystem services, progress may appear slower but our models will be substantially more robust and informative about the effects of environmental change. [source] JTruss: A CAD-oriented educational open-source software for static analysis of truss-type structuresCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 4 2008Francesco Romeo Abstract A CAD-oriented software (JTruss) for the static analysis of planar and spatial truss-type structures is presented. Developed for educational purposes, JTruss is part of an open-source project and is characterised by complete accessibility (i.e. platform independent) and high software compatibility. CAD methodologies are employed to implement commands for handling graphic models. A student friendly graphical interface, tailored mainly for structural mechanics introductory courses in engineering and architecture programs, is conceived. Accordingly, the standard sequence involved in the software design, namely pre-processing, processing and post-processing, is implemented aiming to improve the structural behaviour interpretation. © 2008 Wiley Periodicals, Inc. Comput Appl Eng Educ 16: 280,288, 2008; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20150 [source] Collapse of Reinforced Concrete Column by Vehicle ImpactCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2008Hing-Ho Tsang The column slenderness ratio can be in the order of 6,9. Some of these buildings are right next to busy streets and hence continuously exposed to the potential hazard of a vehicle impacting on a column in an accident. In the early part of this study, the ultimate energy absorption capacity of a reinforced concrete column is compared to the kinetic energy embodied in the moving vehicle. The energy-absorption capacity is calculated from the force-displacement curve of the column as determined from a nonlinear static (push-over) analysis. The ultimate displacement of the column is defined at the point when the column fails to continue carrying the full gravitational loading. Results obtained from the nonlinear static analysis have been evaluated by computer simulations of the dynamic behavior of the column following the impact. Limitations in the static analysis procedure have been demonstrated. The effects of strain rate have been discussed and the sensitivity of the result to changes in the velocity function and stiffness of the impacting vehicle has also been studied. [source] Identification of Modal Combinations for Nonlinear Static Analysis of Building StructuresCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2004Sashi K. Kunnath An increasingly popular analytical method to establish these demand values is a "pushover" analysis in which a model of the building structure is subjected to an invariant distribution of lateral forces. Although such an approach takes into consideration the redistribution of forces following yielding of sections, it does not incorporate the effects of varying dynamic characteristics during the inelastic response. Simple modal combination schemes are investigated in this article to indirectly account for higher mode effects. Because the modes that contribute to deformations may be different from the modes that contribute to forces, it is necessary to identify unique modal combinations that provide reliable estimates of both force and deformation demands. The proposed procedure is applied to typical moment frame buildings to assess the effectiveness of the methodology. It is shown that the envelope of demands obtained from a series of nonlinear static analysis using the proposed modal-combination-based lateral load patterns results in better estimation of inter-story drift, a critical parameter in seismic evaluation and design. [source] On the evaluation of seismic response of structures by nonlinear static methodsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 13 2009Melina Bosco Abstract In the most recent seismic codes, the assessment of the seismic response of structures may be carried out by comparing the displacement capacity, provided by nonlinear static analysis, with the displacement demand. In many cases the code approach is based on the N2 method proposed by Fajfar, which evaluates the displacement demand by defining, as an intermediate step, a single degree-of-freedom (SDOF) system equivalent to the examined structure. Other codes suggest simpler approaches, which do not require equivalent SDOF systems, but they give slightly different estimation of the seismic displacement demand. The paper points out the differences between the methods and suggests an operative approach that provides the same accuracy as the N2 method without requiring the evaluation of an equivalent SDOF system. A wide parametric investigation allows an accurate comparison of the different methods and demonstrates the effectiveness of the proposed operative approach. Copyright © 2009 John Wiley & Sons, Ltd. [source] Natural and accidental torsion in one-storey structures on elastic foundation under non-vertically incident SH-wavesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2006Javier Avilés Abstract Factors , and , used in equivalent static analysis to account for natural and accidental torsion are evaluated with consideration of soil,structure interaction. The combined torsional effects of structural asymmetry and foundation rotation are examined with reference to a single monosymmetric structure placed on a rigid foundation that is embedded into an elastic half-space, under to the action of non-vertically incident SH waves. Dynamic and accidental eccentricities are developed such that when used together with the code-specified base shear, the resulting static displacement at the flexible edge of the building is identical to that computed from dynamic analysis. It is shown that these eccentricities do not have a unique definition because they depend on both the selection of the design base shear and the criterion used for separation of the torsional effects of foundation rotation from those of structural asymmetry. Selected numerical results are presented in terms of dimensionless parameters for their general application, using a set of appropriate earthquake motions for ensuring generality of conclusions. The practical significance of this information for code-designed buildings is elucidated. Copyright © 2006 John Wiley & Sons, Ltd. [source] A modal pushover analysis procedure to estimate seismic demands for unsymmetric-plan buildingsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2004Anil K. Chopra Abstract An Erratum has been published for this article in Earthquake Engng. Struct. Dyn. 2004; 33:1429. Based on structural dynamics theory, the modal pushover analysis (MPA) procedure retains the conceptual simplicity of current procedures with invariant force distribution, now common in structural engineering practice. The MPA procedure for estimating seismic demands is extended to unsymmetric-plan buildings. In the MPA procedure, the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by non-linear static analysis using the inertia force distribution for each mode, which for unsymmetric buildings includes two lateral forces and torque at each floor level. These ,modal' demands due to the first few terms of the modal expansion are then combined by the CQC rule to obtain an estimate of the total seismic demand for inelastic systems. When applied to elastic systems, the MPA procedure is equivalent to standard response spectrum analysis (RSA). The MPA estimates of seismic demand for torsionally-stiff and torsionally-flexible unsymmetric systems are shown to be similarly accurate as they are for the symmetric building; however, the results deteriorate for a torsionally-similarly-stiff unsymmetric-plan system and the ground motion considered because (a) elastic modes are strongly coupled, and (b) roof displacement is underestimated by the CQC modal combination rule (which would also limit accuracy of RSA for linearly elastic systems). Copyright © 2004 John Wiley & Sons, Ltd. [source] The distributional effects of carbon and energy taxes: the cases of France, Spain, Italy, Germany and UKENVIRONMENTAL POLICY AND GOVERNANCE, Issue 4 2002Dr. E. J. Symons This paper examines the likely immediate impact effect of some pollution taxes on the tax burden of households in a number of European countries. The total effect on households of such taxes is assessed using input,output analysis. Thus both the direct effect of taxes, through increased fuel prices, and the indirect effect, through increased prices of other goods, can be assessed simultaneously. This input,output approach allows the generation of direct plus indirect pollution intensities for all household consumption categories, for, in principle, a number of pollutants (CO2, SO2, NOx, particulates). These intensities could then be used to assess the impact on households of pollution taxes. This paper concentrates on CO2 and energy, performing a static analysis of the effect of a tax on the carbon or energy content of goods using the known consumption patterns for the various countries, both in aggregate and for different income groups. This allows a first assessment of the regressive/progressive effects of such taxes and an indication of consumer welfare loss. Copyright © 2002 John Wiley & Sons, Ltd and ERP Environment. [source] INTEGRATING EVOLUTIONARY AND FUNCTIONAL APPROACHES TO INFER ADAPTATION AT SPECIFIC LOCIEVOLUTION, Issue 9 2010Jay F. Storz Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally, population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests to evaluate whether the functional variation is of adaptive significance. In other cases, studies may be initiated by genome scans of DNA variation to identify candidate loci for recent adaptation. Results of such analyses can then motivate experimental efforts to test whether the identified candidate loci do in fact contribute to functional variation in some fitness-related phenotype. Functional studies can provide corroborative evidence for positive selection at particular loci, and can potentially reveal specific molecular mechanisms of adaptation. [source] Ideas and Change in U.S. Foreign Aid: Inventing the Millennium Challenge CorporationFOREIGN POLICY ANALYSIS, Issue 2 2008Steven W. Hook Recent scholarship on foreign policy change focuses on the role of ideas in altering policies and related governing institutions. While a welcome antidote to the previous preoccupation with static analysis, this research has yet to provide adequate understanding of whether and how ideas produce change in specific instances. This study seeks to narrow this gap by examining a recent program change in U.S. foreign aid policy: the creation in 2004 of the Millennium Challenge Corporation (MCC), an independent agency designed to reward the world's most impoverished countries that had previously undertaken neoliberal economic reforms and democratic political reforms. The study identifies a convergence of widely shared principled and causal beliefs which, mediated through U.S. domestic structures, produced the most significant change in U.S. aid strategy and structures in nearly half a century. In melding societal theories that emphasize the role of transnational norm diffusion with theories of domestic politics, the study answers the call for multilevel explanations of foreign policy change. And by applying constructivist notions of ideas and discursive framing with rationalist conceptions of power and interests, the study further responds to the need for theoretical synthesis in the study of foreign policy. [source] Pareto-Improving Redistribution and Pure Public GoodsGERMAN ECONOMIC REVIEW, Issue 2 2000Richard Cornes In the pure public good model, the Nash equilibrium associated with one initial income distribution may Pareto dominate the equilibrium associated with another distribution of the same aggregate income. We explore this possibility and examine its implications for Pareto-improving policy intervention by undertaking a comparative static analysis of Pareto-improving tax-financed increases in pure public good provision. Under some circumstances, a government can engineer policies that raise public good provision while increasing the well-being of contributors and non-contributors. Crucial factors promoting this outcome involve a large number of non-contributors, a high marginal valuation for the public good by non-contributors and a large aggregate response of contributors to changes in their income. [source] Optimal vibration control of continuous structures by FEM: Part I,the optimality equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2002W. Szyszkowski Abstract The governing equations of the problem of optimal vibration control of continuous linear structures are derived in the form of a set of fourth-order ordinary differential equations in the time domain. The equations decouple in the modal space and become suitable for handling by the FEM technique with the time domain subdivided into ,finite time' elements of class C1. It is demonstrated that the standard beam element with cubic Hermitian interpolation functions, routinely used in a static analysis of beams, can conveniently be substituted for the required ,finite time' element. Copyright © 2002 John Wiley & Sons, Ltd. [source] Free vibrations of shear-flexible and compressible arches by FEMINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2001Przemyslaw Litewka Abstract The purpose of this paper is to analyse free vibrations of arches with influence of shear and axial forces taken into account. Arches with various depth of cross-section and various types of supports are considered. In the calculations, the curved finite element elaborated by the authors is adopted. It is the plane two-node, six-degree-of-freedom arch element with constant curvature. Its application to the static analysis yields the exact results, coinciding with the analytical ones. This feature results from the use of the exact shape functions in derivation of the element stiffness matrix. In the free vibration analysis the consistent mass matrix is used. It is obtained on the base of the same functions. Their coefficients contain the influences of shear flexibility and compressibility of the arch. The numerical results are compared with the results obtained for the simple diagonal mass matrix representing the lumped mass model. The natural frequencies are also compared with the ones for the continuous arches for which the analytically determined frequencies are known. The advantage of the paper is a thorough analysis of selected examples, where the influences of shear forces, axial forces as well as the rotary and tangential inertia on the natural frequencies are examined. Copyright © 2001 John Wiley & Sons, Ltd. [source] The Effect of a Change in Wages on Welfare in a Two,Class Monocentric CityJOURNAL OF REGIONAL SCIENCE, Issue 1 2003Youngsun Kwon This paper performs a comparative static analysis to derive the effect of a change in the wages of the rich living in the suburban area of a city on the welfare of the poor living in the central area of the city. It assumes that commuting cost is a function of distance and wages. A sufficient condition for an increase in the wages of the rich to harm the welfare of the poor is that the time cost of commuting is greater than the operating cost of commuting. [source] How Does Economic Development in Eastern Europe Affect Austria's Regions?JOURNAL OF REGIONAL SCIENCE, Issue 2 2002A Multiregional General Equilibrium Framework The paper quantifies regional welfare effects arising from the increasing trade flows between Austria and its Eastern neighbors after the opening up of Eastern Europe. We calibrate a static multiregional Computable General Equilibrium (CGE) model with benchmark data from 1994 for Austria, subdivided into nine Federal Provinces. The regions are linked by trade flows with the four Eastern neighboring countries and with the rest of the world. We simulate the effects of the increase of trade interpenetration as observed between 1989 and 1999 in a comparative static analysis. Regional welfare effects under fixed and flexible wages are presented. We also compare national CGE results with estimates obtained in a simple partial equilibrium approach. [source] The Exclusion Theorem in the Weberian SpaceJOURNAL OF REGIONAL SCIENCE, Issue 1 2000Song-Ken Hsu In this paper we employ a unifying approach to examine the exclusion theorem in a Weberian space under various types of uncertainty: input price or output price uncertainty, transport rate uncertainty, and technology uncertainty. The novelty of our approach is the usage of second-order conditions and comparative static analysis in the derivation of conditions for thevalidity of the exclusion theorem. Our main results are new and some are generalizations of those obtained in prior studies. [source] An exact sinusoidal beam finite elementPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2008Zdzislaw Pawlak The purpose of the paper is to derive an efficient sinusoidal thick beam finite element for the static analysis of 2D structures. A two,node, 6,DOF curved, sine,shape element of a constant cross,section is considered. Effects of flexural, axial and shear deformations are taken into account. Contrary to commonly used curvilinear co,ordinates, a rectangular co,ordinates system is used in the present analysis. First, an auxiliary problem is solved: a symmetric clamped,clamped sinusoidal arch subjected to unit nodal displacements of both supports is considered using the flexibility method. The exact stiffness matrix for the shear,flexible and compressible element is derived. Introduction of two parameters "n" and "t" enables the identification of shear and membrane influences in the element stiffness matrix. Basing on the principle of virtual work a full set of 18 shape functions related to unit support displacements is derived (total rotations of cross,sections, tangential and normal displacements along the element). The functions are found analytically in the closed form. They are functions of one linear dimensionless coordinate of x,axis and depend on one geometrical parameter of sinusoidal arch, height/span ratio "c" and on physical and geometrical properties of the element cross,section. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] AN OBTRUSIVE REMARK ON CAPITAL AND COMPARATIVE STATICSMETROECONOMICA, Issue 1 2009Gaetano Bloise ABSTRACT We present a simple comparative statics analysis of steady-state equilibria in overlapping generations economies with capital accumulation. We regard comparative statics as paradoxical whenever an exogenous increase in saving propensity induces a decrease (an increase) in consumption at the steady state when interest rate is positive (negative). It is shown that there is an exact relation between paradoxical comparative statics and a perverse intersection of properly identified curves of demand for and supply of capital in value. The demand curve for capital in value coincides with that of neo-Ricardian analysis. We relate our conclusions to some old and recent issues in capital theory. [source] Locational tying of complementary retail itemsNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 5 2009Bacel Maddah Abstract We study a selling practice that we refer to as locational tying (LT), which seems to be gaining wide popularity among retailers. Under this strategy, a retailer "locationally ties" two complementary items that we denote by "primary" and "secondary." The retailer sells the primary item in an appropriate "department" of his or her store. To stimulate demand, the secondary item is offered in the primary item's department, where it is displayed in very close proximity to the primary item. We consider two variations of LT: In the multilocation tying strategy (LT-M), the secondary item is offered in its appropriate department in addition to the primary item's department, whereas in the single-location tying strategy (LT-S), it is offered only in the primary item's location. We compare these LT strategies to the traditional independent components (IC) strategy, in which the two items are sold independently (each in its own department), but the pricing/inventory decisions can be centralized (IC-C) or decentralized (IC-D). Assuming ample inventory, we compare and provide a ranking of the optimal prices of the four strategies. The main insight from this comparison is that relative to IC-D, LT decreases the price of the primary item and adjusts the price of the secondary item up or down depending on its popularity in the primary item's department. We also perform a comparative statics analysis on the effect of demand and cost parameters on the optimal prices of various strategies, and identify the conditions that favor one strategy over others in terms of profitability. Then we study inventory decisions in LT under exogenous pricing by developing a model that accounts for the effect of the primary item's stock-outs on the secondary item's demand. We find that, relative to IC-D, LT increases the inventory level of the primary item. We also link the profitability of different strategies to the trade-off between the increase in demand volume of the secondary item as a result of LT and the potential increase in inventory costs due to decentralizing the inventory of the secondary item. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009 [source] | |||||||||||||||||||