Abstract
This paper presents a computational method for a confidence region of identified parameters which are affected by measurement noise and error contained in prescribed parameters. The method is based on sensitivities of the identified parameters with respect to model parameter error and measurement noise along with the law of error propagation. By conducting numerical experiments on simple models, it is confirmed that the confidence region coincides well with the results of numerical experiments. Furthermore, the optimum arrangement of sensor locations is evaluated when uncertainty exists in prescribed parameters, based on the concept that square sum of coefficients of variations of identified results attains minimum. Good agreement of the theoretical results with those of numerical simulation confirmed validity of the theory.
Address
Tetsushi Kurita, Seismic Engineering Department, Tokyo Electric Power Services Co. Ltd., Higashi-Ueno 3-3-3, Taito-ku, Tokyo 110-0015, Japan Kunihito Matsui, Department of Civil Engineering, Tokyo Denki University, Hatoyama, Hiki, Saitama 350-0394, Japan
Abstract
This paper presents the convected material frame approach to study the nonlinear behavior of inelastic frame structures. The convected material frame approach is a modification of the co-rotational approximation by incorporating an adaptive convected material frame in the basic definition of the displacement vector and strain tensor. In the formulation, each discrete element is associated with a local coordinate system that rotates and translates with the element. For each load increment, the corresponding strain-displacement and nodal force-stress relationships are defined in the updated local coordinates, and based on the updated element geometry. The rigid body motion and deformation displacements are decoupled for each increment. This modified approach incorporates the geometrical nonlinearities through the continuous updating of the material frame geometry. A generalized nonlinear function is used to derive the inelastic constitutive relation and the kinematic hardening is considered. The equation of motion is integrated by an explicit procedure and it involves only vector assemblage and vector storage in the analysis by assuming a lumped mass matrix of diagonal form. Several numerical examples are demonstrated in close agreement with the solutions obtained by the ANSYS code. Numerical studies show that the proposed approach is capable of investigating large deflection of inelastic planar structures and providing an excellent numerical performance.
Key Words
convected material frame approach; explicit finite element analysis; inelastic frame structures.
Address
Yaw- Jeng Chiou, Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan 701, R.O.C. Yeon-Kang Wang, Department of Civil Engineering, Chung-Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan 335, R.O.C. Pang-An Hsiao and Yi-Lung Chen, Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan 701, R.O.C.
Abstract
In this study, a new functional is obtained for folded plates with geometric (kinematic) and dynamic (natural) boundary conditions. This functional is the combination of two different functionals. Both functionals are obtained for thick plates which carry in-plane and lateral forces. A new mixed finite element is developed with 4
Key Words
Reissner plate; folded plate; mixed-finite element.
Address
Nihal Eratli and A. Yalcin Akoz, Faculty of Civil Engineering, Istanbul Technical University, 80626 Maslak-Istanbul,Turkey
Abstract
Static and dynamic penetration tests of reinforced concrete (RC) slab specimens are described and discussed. The experimental study was aimed at a better understanding of mechanisms that are involved in dynamic penetration, through their identification in static tests, and by establishing their relative influence in similar dynamic cases. The RC specimens were 80
Key Words
impact; penetration; perforation; reinforced concrete barriers.
Address
Avraham N. Dancygier and David Z. Yankelevsky, Department of Civil Engineering and National Building Research Institute, Technion, Technion City, Haifa 32000, Israel
Abstract
The infrastructure system in the United States has been aging faster than the resource available to restore them. Therefore decision for allocating the resources is based in part on the condition of the structural system. This paper proposes to use neural network to predict the overall rating of the structural system because of the successful applications of neural network to other fields which require a
Key Words
infrastructure; systems; evaluation; bridges; ratings; neural networks.
Address
Augusto V. Molina, Parson Transportation Group, New York, U.S.A. Karen C. Chou, Department of Mechanical & Civil Engineering, Minnesota State University, Mankato, MN 56001, U.S.A.
Abstract
The objective of this study is to investigate the dynamic behavior of elastic beams subjected to moving loads. Although analytical methods are available, they have limitations with respect to complicated structures. The use of computer technology in recent years is an effective way to solve the problem; thus using the latest technology this study establishes a finite-element solution procedure to investigate dynamic behaviors of a typical elastic beam having a set of constant geometric properties and various span lengths. Both the dead load of the beam and traffic load are applied in which the traffic load is considered a concentrated moving force with various traveling passage speeds on the beam. Dynamic behaviors including deflection, shear, and bending moment due to moving loads are obtained by both analytical and finite element methods; for simple structures, they have an excellent agreement. The numerical results show that based on analytical methods the fundamental mode is good enough to estimate the dynamic deflection along the beam, but is not sufficient to simulate the total response of the shear force or the bending moment. The linear dynamic behavior of the elastic beams subjected to multiple exciting loads can easily be found by linear superposition, and the geometric nonlinear results caused by large deformation and axial force of the beam are always underestimated with only a few exceptions which are indicated. In order to make the results useful, they have been nondimensionalized and presented in graphical form.
Key Words
dynamic; characteristics; beams; bridges; moving loads; traffic loads.
Address
Chia-Chih Tang, Department of Civil Engineering, Chinese Military Academy, 1 Wei-Wu Rd. Feng-Shan, 83000, Taiwan, R.O.C. Yang-Cheng Wang, Academic Affairs Development Office, National Defense University, 156 Chung-Shin Rd. Lung-Tang, 32500, Tao-Yuan, Taiwan, R.O.C.
Abstract
The problem of dynamic analysis of truss structures based on probability is studied in this paper. Considering the randomness of both physical parameters (elastic module and mass density) of structural materials and geometric dimension of bars respectively or simultaneously, the stiffness and mass matrixes of the elements and structure have been built. The structure dynamic characteristic based on probability is analyzed, and the expressions of numeral characteristics of inherence frequency random variable are derived from the Rayleigh
Key Words
truss structure; physical parameter; geometric dimension; random variables; dynamic characteristic analysis.
Address
J.J. Chen, J.W. Che, H.A. Sun, H.B. Ma and M.T. Cui, School of Electronic Mechanical Engineering, Xidian University, Xi
