An efficient curved beam element compatible with the shell element is developed for the modelling of stiffeners which may have different lamination schemes. Load—deflection plots and backbone curves in non-dimensional planes are presented as results. A finite element formulation for panel behavior considering general loading conditions, material properties, geometry, boundary conditions, and initial deflections is presented. Little information and few guidelines are available in current codes of practice to feed the engineering demands of the mining industry. All the results are close to the published results. The interaction between serviceability and ultimate limit states is then highlighted. Numerical examples are presented to show the accuracy and convergence characteristics of the element.
Special Design Issues--Fire Protection Committee, David L. Few guidelines are available in North American and European codes of practice for practitioners to effectively design pipe racks. The presented procedure is confirmed to be highly accurate. This paper presents solutions which simplify the elastic large deflection analysis of compressed plates. Summary The main purpose of this paper is to illustrate the use of the stability functions for long plates in combined compression and shear defined in a previous paper by the authors.
The stiffened panel is then modeled as an equivalent orthotropic plate, for which the various elastic constants characterizing structural orthotropy are determined in a consistent systematic manner using classical theory of elasticity. Finally, extensive results are presented to investigate the buckling behavior of multi-stiffened plates. Previous papers by the authors and others have developed exact methods for computing the critical buckling loads of prismatic assemblies of rigidly interconnected thin flat rectangular plates. Furthermore, analytical expressions are required to compute the reduction in the stiffness induced due to the structural or material defects. By transforming the stiffened panel to an equivalent orthotropic plate, ultimate strength formulations for slightly stiffened panels subject to uniaxial or biaxial compressive loads are derived based on large deflection theory and overall buckling mode. The potential energy of the structure is first expressed in terms generalized functions that describe the longitudinal and transverse displacement profiles. The static problem is solved through an iterative scheme and the dynamic problem is solved with the static displacement field as an initial guess.
This modelling strategy has helped to reduce the number of unknowns significantly compared to the usual approach where solid or shell elements are used for modelling stiffeners. The vibration analysis of stiffened plates using hierarchical finite elements with a set of local trigonometric interpolation functions is presented. A method is proposed for calculating the strength of stiffened steel compression flanges. Guidelines are then provided for steel fabricators to achieve economical sections to be used in practice. A good understanding and knowledge of the structural performance is a fundamental step to achieve this target.
The procedure is very practical and can be utilized in the industry for the analysis of box girders. It is meant to be a 'liberal' document in the sense that it promotes new, innovative and bold yet prudent designs by sharing the experience of the authors, summarizing specifications given in codes, and presenting a collection of examples of well-designed structures or structural details from around the world. KeywordsUnconstrained optimization-Steel structures-Dynamic analysis The paper offers to practitioners economical procedures that can be utilized to optimize the design of built up box sections subject to compression and biaxial bending. Explicit expressions are derived for the elements of the matrices, in which all the essential destabilizing effects of the basic stresses, as well as dynamic effects, are included. The sensitivity the natural frequency to the stiffener sizes and configurations is illustrated. The bases of these programs are the exact and approximate Finite Strip methods. The governing equations are derived using the principle of virtual work, integrated numerically using Gauss quadrature and solved by Newton—Raphson iteration.
The continuous improvements in oil sand recovery procedures have generated engineering and environmental challenges that are rarely encountered in other conventional oil and gas or petrochemical projects. An essential feature is the use of an 'effective yield' approach for dealing with the interaction between local and overall buckling, instead of the 'effective section' method. Other results cover critical loads other than the lowest, panels with bulb flat stiffeners, as used for bridge decks, and the effects of assumptions usually made when idealizing real panels before computation. The model presented in this paper can also be easily modified to solve the problems of stiffened piezolaminated plates and shells, or plates and shells with piezoelectric material patches. The results demonstrate the way in which panel capacity varies with stiffener size for a full range of geometries, and concludes that stiffener bending rigidity is the major design consideration. In each sub-region, the formulation is formed by coupling boundary element formulations of shear deformable plate bending and two-dimensional plane stress elasticity.
Numerical solutions are presented for a series of plates stiffened by flats, for a range of panel slenderness ratios and stiffener rigidities. Vibration mode shapes along with contour plots are provided in a few cases. A recent paper by Chilver covers the same ground from the mathematical point of view and the purpose of the present paper is to illustrate the practical application of the method to familiar problems in the computation of initial buckling stress for sheet-stiffener combinations. Mathematical formulation is based on a variational form of energy principle, and a solution technique, where static analysis serves as the basis for the subsequent dynamic study, is followed. The optimization procedures to minimize the weight of the structure are also reviewed. . Way Wind-moment design of unbraced composite frames Steel Construction Institute 2000 1859421148, 9781859421147 211 Anna M.
Geometric non-linearity arising out of large deflection is accounted for by consideration of non-linear strain-displacement relations. Up to 60% increase can be achieved by using appropriate number of longitudinal and transverse stiffeners. The structural idealization, the theoretical basis and the merits of these methods are also discussed. The panel can be composed of various shapes of stiffeners. It is also shown that the shear buckling stress may vary by 40% with the current design expressions.