Portal frame

About: Portal frame is a research topic. Over the lifetime, 1778 publications have been published within this topic receiving 7210 citations.

Method and device for cutting silicon core trimmings into finished silicon core products

Abstract: The invention discloses a method and device for cutting silicon core trimmings into finished silicon core products. The device comprises a machine frame, a portal frame, a moving mechanism, a wire winding-unwinding mechanism and a clamping mechanism; the portal frame is installed on the machine frame through the moving mechanism and driven to do linear reciprocating motion on the machine frame; the portal frame is provided with a lifting part and a cutting head installed on the lifting part; the wire winding-unwinding mechanism is installed at one end of the machine frame and connected with the cutting head through a cutting wire; and the clamping mechanism is arranged on the machine frame. The method and device for cutting the silicon core trimmings into the finished silicon core productsare high in working efficiency, small in loss, capable of reducing energy consumption and high in silicon rod utilization rate.

Nonlinear FE Analyses of RC Bridge Frame Corners, Based on Fracture Mechanics

Abstract: Reinforced concrete frame corners were analyzed using the nonlinear finite-element method and fracture mechanics. The objective of the study was to determine whether the reinforcement detailing in frame bridges could be simplified, with preserved structural safety, by splicing the reinforcement within the frame corner. A constitutive model for concrete, based on nonlinear fracture mechanics and plasticity, was used. An interface model was used to account for slip between the reinforcement and surrounding concrete. Analysis of previously tested frame specimens, with both spliced and unspliced corner reinforcement, was used to study the overall behavior of the frames; more detailed analysis of only the frame corner regions was used to study the influence of the reinforcement splices. The analyses were found to reflect the mechanical behavior of the specimens, and are in good agreement with the test results. The analysis results support, together with the test results, the idea that it would be feasible to splice all reinforcement in a portal frame bridge within the corner regions.

Analytical model to evaluate the equivalent viscous damping of timber structures with dowel-type fastener connections

Abstract: The Equivalent Viscous Damping (EVD) parameter is used to simplify the dynamic problem, passing from a non-linear solution of the system to a simple linear-elastic one. In the case of Direct Displacement-Based seismic Design (DDBD) methods, the EVD value allows direct design of structures, without an iterative computational process. This paper proposes a rational analytical formula to evaluate the EVD value of timber structures with dowel-type metal fastener connections. The EVD model is developed at the ultimate limit state, as a solution of the equilibrium problem related to an inelastic configuration. For a specific joint configuration, the EVD predicted via an analytical model was compared to experimental results. The proposed EVD model was validated using non-linear dynamic analysis on a portal frame, built with dowel-type fasteners arranged in two concentric crowns.

On Estimating the Seismic Displacement Capacity of Timber Portal-Frames

Abstract: An analytical model is proposed to estimate the seismic displacement capacity, at serviceability and ultimate limit states, of timber portal frame structures with dowelled joints. The predictions from the simplified formula are compared with the results of numerical analyses carried out on a sample of representative cases. These cases result from a simulated design procedure, consistent with Eurocode 8, and are generated via Monte Carlo sampling, with varying sizes, materials and load conditions and also uncertainties in these parameters. Based on the outcome of the analysis we propose a set of practical formulas which allow prediction of the displacement with a given percentile of overestimates. In addition, it is shown that these equations for displacement capacity can be used to generate fragility curves for performance-based earthquake engineering applications. Prescription of an overstrength factor in code provisions is recommended to avoid brittle failure.