Papers by Keyword: Frames

Abstract: Numerous existing steel framed buildings located in earthquake prone regions world-wide were designed without seismic provisions. Slender beam-columns, as well as non-ductile beam-to-column connections have been employed for multi-storey moment-resisting frames (MRFs) built before the 80’s. Thus, widespread damage due to brittle failure has been commonly observed in the past earthquakes for steel MRFs. A recent post-earthquake survey carried out in the aftermath of the 2016-2017 Central Italy seismic swarm has pointed out that steel structures may survive the shaking caused by several main-shocks and strong aftershocks without collapsing. Inevitably, significant lateral deformations are experienced, and, in turn, non-structural components are severely damaged thus inhibiting the use of the steel building structures. The present papers illustrates the outcomes of a recent preliminary numerical study carried out for the case of a steel MRF building located in Amatrice, Central Italy, which experienced a series of ground motion excitations suffering significant damage to the masonry infills without collapsing. A refined numerical model of the sample structure has been developed on the basis of the data collected on site. Given the lack of design drawings, the structure has been re-designed in compliance with the Italian regulations imposed at the time of construction employing the allowable stress method. The earthquake performance of the case study MRF has been then investigated through advanced nonlinear dynamic analyses and its structural performance has been evaluated according to Eurocode 8-Part 3 for existing buildings. The reliability of the codified approaches has been evaluated and possible improvements emphasized.

Abstract: Precast structures for multi-storey buildings can be designed with economy, safety and high performance. However, depending on the height of the building and the intensity of the lateral loads, the lateral stability system must be carefully chosen in order to maximize the global structural performance. In Brazil, the most common method for lateral stability is achieved by moment resisting precast-frames, wherein the moment-rotation response of the beam-column connections are responsible to provide the frame action, which will govern the distribution of internal forces and the sway distribution along the building height. On the other hand, in Europe, bracing systems comprised by shear walls or infill walls are mostly used, wherein beam-column connections are designed as hinged. The aim of this paper is to present a comparison between these methods for lateral stability, applying nine structural simulations with moment resisting precast-frames, shear walls and infill walls solutions, divided in three groups - 3 building with 5 storeys (21 meters high), 3 buildings with 10 storeys (41 meters high) and 3 building with 20 storeys (81 meters high). All first storeys are 5 meters high, while all the others are 4 meters high. The results from all structural analyses are compared. As conclusion, while moment-resisting beam-column connections are more feasible for applying in low-rise precast buildings, the use of shear walls and infill walls are more efficient for tall buildings due to decrease of lateral displacements, having a reduction of second order effects but also increasing the reactions at the foundations of bracing elements.

Abstract: Frames are the main components of the flight motion simulator, which are the support for each shaft system, at the same time the rotating load for the external shaft, so the stiffness and dynamic characteristics of the frames in a large extent determines the final accuracy and dynamic performance of the flight motion simulator. For the cast aluminum alloy ZL114A frames of a 3-DOF flight motion simulator, using finite element analysis method, the dynamic characteristics are calculated and analyzed, and then the each order resonance frequency and mode of vibration are obtained. By using of the modal synthesis method and optimization algorithms, the structural dynamics of frames are designed optimally, so as to further reducing the moment of inertia, and improving the stiffness and dynamic characteristics of frames. This method has provided important reference for the reasonable design of the frame structure, and definitively established the foundation to further study the triaxial coupling dynamic characteristics and system mechanical optimization for the flight motion simulator.

Abstract: Frame theory plays an important role in field of the engineering and technology because of their redundancy properties. In this paper, symmetric fusion frames with several generators are constructed from any fusion frames given, which generalizes the existing result to the case of several generators. This way makes the amount of wavelets largely increase.

Abstract: The multimedia technology has been widely applied to many engineering fields. However, because the data contained in video content is very large, it is always being a difficult problem of computer data analysis and processing to analyze the video. Based on the content analysis, this paper takes use of many technologies aimed at the problem of video, such as analysis and processing of multimedia, simulation classification of computer and computer vision and so on. At the same time, combined with the model of color information semantics and the real target tracking principle, this paper builds model and designs the algorithm for the video simulation. At last, this paper makes trajectory extraction and recognition for the real process goals of football, establishing the simulation process of football. Through the numerical simulation, it is found that frames extracted from the video capture are different from each other in the process of real football game and the recognition rate and accuracy of simulation trajectory are also not the same. Among them, when frame is 85, the effects of recognition rate and accuracy are best, which respectively reach 80% and 89%. Thus, it gains a better simulation effect.

Abstract: Frames play an important role in field of the engineering and technology. In this paper, symmetric wave packet frames are constructed, which generalizes the existing result to the general case. This way makes the amount of wavelets largely increase.

Abstract: The notion of trivariate normalized tight frames and a generalized multiresolution struc-ture and the concept of subspace trivariate affine pseudoframes are introduced. The pyramid decom-position scheme of a generalized multiresolution structure (GMRS) is established, which is generaliz-ation of Mallat's pyramid algorithm. A necessary and sufficient condition for the existence of the pyramid decomposition scheme of space is presented. Moreover, affine trivariate pseudo frame expansions of are constructed by virtue of the pyramid decomposition scheme.

Abstract: The multiwavelet has more desired properties than any single wavelet, such as short support, symmetry, and smoothness. In this paper, symmetric multiwavelet frames with general lattice and with any symmetric points are constructed from multiwavelet frames given. The existing result is generalized to the case of general lattice.

Abstract: Frames play an important role in signal processing, image processing, data compression and sampling theory. In this paper, symmetric multiwavelet frames with general composite dilation and with any symmetric points are constructed from composite dilation multiwavelet frames given. At last, an example is provided to prove the theory.

Abstract: Finite element analysis is undertaken to identify the extent of loading deformation of instrumented indentation equipment frame which is a main part in High-precision instrumented indentation tester developed and realized by our group. The working load enacted in the model is varied from 10N to 100N, and the increment load is 10N. By plotting and fitting data of inclination angle and working load, the relationship between frame inclination angle and working load is established. The function of this relationship is θ=0.000024*F. When the working load is up to the upper bound 100N, the inclination angle of frame reaches the maximum value 0.00241°.Load analysis of push rod shows that the percent error between measured load values and real indentation load values caused by maximum inclination angle is in 10-8order. The conclusion is thus derived that frame inclination has nearly no effects on load measurement precision. The research in this paper confirms that the design of frame belonging to High-precision instrumented indentation tester is appropriate.