Stability Analysis of the Radiant Cable Suspendome

The Suspended Latticed Intersected Cylindrical Shell (SLICS) is a new structural system, composed by the single layer Latticed Intersected Cylindrical Shell (LICS) and the prestressed cable-strut system. Mechanical properties of this structure were investigated through nonlinear buckling analysis by the consistent imperfect buckling analysis method, compared with the single layer LICS. Structure parameters including prestress level, member section, length of bar, rise-span ratio, obliquity were analyzed. And the effect of material nonlinearity on the stability was studied. Results show that the ultimate bearing capacity of the SLICS is improved as the introduction of prestress. However the prestress level has a limited impact on the ultimate bearing capacity. And the material nonlinear is very important to the stability of the SLICS.

Discretized stability analysis for continua is described for two different versions, named linear elastic buckling analysis and nonlinear elastic buckling analysis. These approaches include eigenvalue problems with different formulations. Linear buckling analysis is often non-reliable and therefore nonlinear buckling analysis, based on Green-Lagrange strains, is described in more detail.

Buckling analysis of structures can be divided into eigenvalue buckling analysis and nonlinear buckling analysis. In this paper, the basic theory of eigenvalue buckling analysis and nonlinear buckling analysis has been described, then using ABAQUS to do eigenvalue buckling analysis and nonlinear buckling analysis on structural elements of an actual project which have prestress, and comparing their ultimate bearing capacity under these two analysis. Meanwhile, during the nonlinear buckling analysis, this paper shows the change of the ultimate load capacity of the structural elements under different prestress and different initial imperfection. Finally, conclusions are summarized.

In the external buckling analysis, it is significant to determine the magnitude of the critical buckling load value. This paper introduces a method based on ANSYS finite element method for external pressure buckling analysis of pressure vessels and determination the critical loads. Eigenvalue buckling analysis and nonlinear buckling analysis are introduced. After the initial selection of structural parameters and reasonable structural design, ANSYS software was used to establish a reasonable and valid 3D solid model. Check the design and hydraulic condition is necessary after establishing the 3D solid model. It is the precondition of buckling analysis. After passing the internal pressure strength test, external buckling analysis will be start. In this paper, the buckling critical load of a 1500m3 spherical tank is obtained by comparing the eigenvalue buckling analysis with the nonlinear buckling. And the value of nonlinear buckling is lower. Because nonlinear buckling analysis considers the flaws of the actual structure. Therefore, nonlinear bucking analysis is more suitable for practical engineering analysis.

This investigation is concerned with the free vibration and seismic response of single-layer cylindrical lattice shells. The effects of basic structural parameters such as the ratio of rise to span, mass, damping, the ratio of length to span and the rigidity of supports, on the dynamic behaviour of single-layer cylindrical lattice shells are investigated in detail. In this paper the finite-element method is used, in which three-dimensional beam elements are employed. Both the natural frequencies and their associated modes of vibration are obtained with a subspace iteration technique, and the direct dynamic analysis method is adopted to analyse the dynamic responses of single-layer lattice shells under vertical and horizontal earthquake excitations. The objective of this study is to achieve a better understanding of the dynamic characteristics and seismic behaviour of single-layer lattice shells. The results are valuable for the earthquake-resistant design of such structures.

Optimal design of composite lateral wing upper covers. Part II: Nonlinear buckling analysis

Failure of delaminated interply hybrid composite plates under compression

Stiffeners are typically used to strengthen structures that rely on plates for load bearing. Such structures are subjected to various kinds of in-plane and out-of-plane loading over its lifespan. Furthermore, cutouts in aerospace structures are considered for practical and design reasons. In the present paper, finite element method is used for the analysis of a flat rectangular stiffened plate. Static analysis is performed on three panels with different stiffener cross sections (I section, hat section and rectangular section), and the panel with the least deformation and stress is chosen for further buckling analysis. Linear, non-linear and post buckling analysis of the selected stiffened panel under in-plane compression is carried out and its load and end – shortening response is evaluated till collapse. Furthermore, the effect of rectangular and circular central cutouts on the buckling behaviour of the stiffened panel is investigated. By varying the dimensions of the cutouts, a parametric study on buckling and ultimate collapse strength is performed. The study takes into account an aluminium alloy with isotropic material properties and a carbon fibre reinforced polymer (CFRP) with orthotropic material properties.

Recent research trends have indicated an interest in High-Altitude, Long-Endurance (HALE) aircraft as a low-cost alternative to certain space missions. These missions require a lightweight vehicle operating at low speeds, high lift and minimum drag. These conditions necessitate high-aspect ratio wings. Due to its large span and light weight, the wing structure is very flexible. The wings undergo significant deflections as a result of the fluid loads acting on them, and require the consideration of aeroelastic effects. To reduce the structural deformation and increase the total lift, a sensorcraft model with a joined-wing configuration is employed. The results of the simulation of the complex, three-dimensional flow past the joined wing of a HALE aircraft are used as an input for the structural analysis. In the existing studies to date, only simplified structural models have been examined. In the present work, a semi-monocoque structural model is developed. All stringers, skin panels, ribs and spars are represented by appropriate elements in a finite-element model. Linear and nonlinear static analyses under the aerodynamic load are performed. The stress distribution in the wing is explored. Starting with a structural model with uniform mass distribution, a design optimization is performed. The optimized model has a maximum stress 42% lower and a maximum deflection 26% lower than obtained for the initial model. Linear and nonlinear buckling analyses are performed as well. The nonlinear analysis yields a critical buckling load 18% lower than that predicted by linear analysis. This paper will discuss the details of the structural modeling as well as the results obtained before and after optimizing the model.

The effects of large-span truss geometry of the double-plane stable orthogonal design. The use of finite element analysis software Midas double space truss were linear buckling analysis and nonlinear buckling analysis, research process and through its buckling load - examine issues outside of the structure of the plane stable displacement curve. For double truss draw some outside reference plane stability study conclusions.

3D wind buckling analysis of long steel corrugated silos with vertical stiffeners

By setting cables and struts in place in the single-layer cylindrical latticed shell, a new-style prestressed spatial steel structure—cable supported barrel vault structure is constructed, obviously, the cable is the most important element in this structure. The static load test research on this structure is carried out and the mechanics feature of cables are mainly investigated. Based on the prototype building, a scale model with the scale of 1∶15 is designed and manufactured for the test. The research results indicate, the cables force in the symmetrical place are nearly same, the cable in the middle has the biggest force, and the force decrease gradually along the longitudinal direction to ends. Moreover, the half-span loading will impair the tense action of cables, which causes the decrease of load-carring capacity of the cable supported barrel vault structure.

Design of Large-scale and light-weight pressure vessels is an inexorable trend of industrial development. These large thin-walled vessels are prone to buckling failure when subjected to compression loads and other destabilizing loads. Thus, buckling analysis is a primary and even the most important part of design for these pressure vessels. Local buckling failure will probably occur when cylindrical shells with nozzle subjected to axial loads. In this paper, a FE model of cylindrical shell with a normal nozzle is established in ANSYS Workbench. The bifurcation buckling analysis is performed by using an elastic-plastic stress analysis with the effect of nonlinear geometry, and a collapse analysis is performed with an initial imperfection. The axial buckling loads are obtained by these two types of method. Some issues about nonlinear buckling analysis are discussed through this study case.

Modern long-span space structures, developed during the 1970s and 1980s, are light and effective structures based on new technologies and light-weight high-strength materials, such as membranes and steel cables. These structures include air-supported membrane structures, cable-membrane structures, cable truss structures, beam string structures, suspen-domes, cable domes, composite structures of cable dome and single-layer lattice shell, Tensairity structures and so forth. For the premodern space structures widely used since the mid-twentieth century (such as thin shells, space trusses, lattice shells and ordinary cable structures), new space structures have been developed by the combination of different structural forms and materials. The application of prestressing technology and the innovation of structural concepts and configurations are also associated with modern space structures, including composite space trusses, open-web grid structures, polyhedron space frame structures, partial double-layer lattice shells, cable-stayed grid structures, tree-type structures, prestressed segmental steel structures and so forth. This paper provides a review of the structural characteristics and practical applications in China of modern rigid space structures, modern flexible space structures and modern rigid-flexible combined space structures.

The pultruded Fiber Reinforced Polymer (PFRP) material manufactured by the “pultrusion” process has many applications in the construction industry. However, the production process involves several difficult-to-control stages, which can lead to material defects. This paper proposes a method to determine the local buckling resistance of FRP composite I column having material imperfection on the flanges and web. The research has shown that the buckling load determined in nonlinear buckling analysis is 15.5% higher than that obtained from eigenvalue solution (linear perturbation analysis). In addition, the post-buckling resistance of the column is 66.4% higher compared to the local buckling load. The author suggests that this modelling and determination method be widely applied to PFRP structures when studying the instability of columns or beams under various loadings and boundary conditions and different combinations of defects.