Papers by Keyword: Updating

Abstract: Structural damage detection has become an important research area since several works [2] were focused on the crack zones detection in order to foresee the appropriate solutions. The present research aims to carry out the reinforced concrete bridge damage detection with the finite element mathematical model updating method (MMUM). Unknown degrees of freedom dof are expanded from measured ones. The partitioned system of equations has provided a large sub-system of equations which can be solved efficiently by handling sparse matrix algorithms at each time step of the finite time centered space FTCS discretization. A new and efficient method for the calculation of the constant strain tetrahedron shape functions has been developed [1,3,4,5,6]. The topological and analytical geometry of the tetrahedron and its useful formulae enabled us to develop its shape functions and its corresponding finite element matrices. The global finite element matrices and sparse matrix computations have been achieved with a calculus source code. The reinforced concrete mixture has been modeled with the mixture laws [16] which led to its material properties matrix as an orthotropic case with 9 constants and 2 planes of symmetry from the generalized Hooke’s law [1]. It is noticed that the material is made of steel, cement, gravels, sand and impurities. The data computations have been implemented with optimized cpu time and data storage using vectorial programming of efficient algorithms [11,12]. The sparse matrix algorithms used in this study are: solution of symmetric systems of equations UTDUd=R, multiplication, addition, transposition, permutation of rows and columns, and ordering of the matrices representations. All the sparse matrices are given in row-wise sparse format.

Abstract: Schedules are management tools. It's important to have a schedule, but it's more important to use it. In this article it is through the proper use of project schedules that management is able to make informed decisions about scheduling activities. This use includes updating the schedules when the schedule information ceases to be useful fort making informed decisions.

Abstract: In this work, a vibration based damage identification technique (VBDIT) is used to determine the presence of damages in metallic structures, using the undamaged structure information as reference. A complex structure is used in order to contrast the results obtained with those reported for techniques previously employed specially on single beam simulated structures. A finite element model of the structure is developed and validated as a support tool for the study. Theoretical and experimental modal analysis techniques were used as the main tool for damage identification.

Abstract: K-dominant skyline query technology reduces the result sets for a dataset with high dimensional spaces, which is more convenient for user to make decision. But all the existent algorithms are for static k, not suitable for dynamic k. To solve this problem, this paper proposed a new idea, updating the k-dominant skyline for new k by computing the partial points based on existent k-dominant skyline. Based on which, two algorithms are proposed for k increasing and decreasing. Furthermore, detailed theoretical analyses and extensive experiments demonstrate that the algorithms can effectively reduce redundant work, and keep the result correctly.

Abstract: The main objective of this paper is aim to take fatigue reliability updating evaluation of hydraulic steel gate based on the Bayes theorem. The fatigue cracks can be detected for existing structures, and fatigue reliability assessment can be updated by the nondestructive inspection. In this paper, based on the probabilistic characteristics for NDI techniques and the Bayes theorem, a fatigue reliability updating assessment model for existing steel gate components is proposed. The results showed that the fatigue reliability will increase with no cracks detected, decrease with unknown cracks detected, and change remarkably with cracks detected.

Abstract: In order to accurately evaluate the reliability of the existing cable-stayed bridge, a method based on inspection information is proposed to update the system reliability. Using Bayesian method and inspection information, the modified model of cable-stayed bridge random variables is established, and then the failure probability of cable-stayed bridge components is updated. The β-T curves of changing rules of inspection information on system reliability index and service life are obtained. The method has been applied to a cable-stayed bridge, the results show that the proposed method is effective to update the system reliability and can predict the residual life of the existing cable-stayed bridges.

Abstract: The paper pursues the exploration of the feasibility and reliability of current damage detection technologies, evaluating their detection capabilities, environmental factors effects, false alarms rate, adaptability to complex geometries, etc. The method to be used is based on finite element modal updating. Three aspects, as outlined below, are covered: testing samples will be aluminium sheets (0.6m x 0.4m x 1.6mm) strengthened with riveted L-shaped stiffeners. Data will be presented from the undamaged specimens. Secondly, the testing of the samples with damage simulated at different places by temporary removal of specific rivets, thus affecting the overall structural characteristics of the structure. The models used for damage identification methods will be fine tuned to properly detect the simulated damages. Finally, using this information, the paper resumes the capabilities of the method to detect and locate the simulated damage.