Abstract
This paper deals with an experimental and numerical study of a mono-strand wedge anchor head mechanism. First, the experimental program is presented and monitored data such as wedge slippage, anchor deflection and strain distributions along external peripheral surfaces of the anchor head are presented and discussed. In accordance with the experimental set up, these data concern only the global behaviour of the mechanism and cannot provide valuable information such as internal stress-strains distributions, stress concentrations and percentage of yielded volume. Therefore, the second part of this paper deals with the development of an efficient numerical finite element model capable of providing mechanism of the core information. The numerical model which includes all kinematics/material/contact non-linearities is first calibrated using experimental data. Subsequently, a numerical study of the anchorage mechanism is performed and its behaviour is compared to the behaviour of a slightly geometrically modified mechanism where the external diameter has been increased by 5 mm. Finally, different topics influencing the anchorage mechanism behaviour are addressed such as lubrication and wedge shape.
Key Words
anchorage; contact finite element; friction; strand; wedge; yielding.
Address
D. Marceau, J. Bastien and M. Fafard, GIREF Research Center, Laval University, Quebec, Canada, G1K 7P4 A. Chabert, Laboratoire Centrale des Ponts et Chaussees, 75732 Paris CEDEX 15, France
Abstract
Analytical solutions and finite element results of laminated composite plates with smart material layers embedded in them are presented in this study. The third-order plate theory of Reddy is used to study vibration suppression characteristics. The analytical solution for simply supported boundary conditions is based on the Navier solution procedure. The velocity feedback control is used. Parametric effects of the position of the smart material layers, material properties, and control parameters on the suppression time are investigated. It has been found that (a) the minimum vibration suppression time is achieved by placing the smart material layers farthest from the neutral axis, (b) using thinner smart material layers have better vibration attenuation characteristics, and, (c) the vibration suppression time is larger for a lower value of the feedback control coefficient.
Key Words
analytical solutions; composite plates; finite element solutions; third-order plate theory; vibration control.
Address
J.N. Reddy and S. Krishnan, Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843-3123, U.S.A.
Abstract
In this paper, experimental investigation into the behavior of reinforced concrete (RC) columns tested under large lateral displacement with four different types of loading arrangements is presented. Each loading arrangement has a different system for controlling the consistency of the loading condition. One of the loading arrangements used three units of link mechanism to control the parallelism of the top and bottom stub of column during testing, and the remaining employed eight hydraulic jacks for the same purpose. The loading systems condition used in this investigation were similar to the actual case in a moment-resisting frame where the tested column was displaced in a double curvature. Ten model column specimens, divided into four series were prepared. Two columns were tested monotonically until collapse, and unless failure took place at an earlier stage of loading, the remaining eight columns were tested under cyclic loading. Test results indicated that the proposed system to keep the top and bottom stubs parallel during testing performed well.
Address
Abdullah and Katsuki Takiguchi, Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan
Abstract
This note presents the main results of an experimental investigation into the mechanical behaviour of a composite sandwich conceived as a lightweight material for naval engineering applications. The sandwich structure is formed by a three-dimensional glass fibre/polymer matrix fabric with transverse piles interconnecting the skins; the core is filled with a polymer matrix/glass microspheres syntactic foam; additional Glass Fibre Reinforced Plastics extra-skins are laminated on the external facings of the filled fabric. The main features of the experimental tests on syntactic foam, skins and sandwich panels are presented and discussed, with focus on both in-plane and out-of-plane responses. This work is part of a broader research investigation aimed at a complete characterisation, both experimental and numerical, of the complex mechanical behaviour of this composite sandwich.
Key Words
mechanical tests; syntactic foam; glass fibre; composite sandwich.
Address
Enrico Papa and Alberto Corigliano, Dipartimento di Ingegneria Strutturale, Facolta di Ingegneria Leonardo, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy Egidio Rizzi, Dipartimento di Ingegneria Civile e Ambientale, Facolta di Ingegneria di Taranto, Politecnico di Bari, Via Orabona 4, I-70125 Bari, Italy
Abstract
This paper presents an experimental modal analysis of perforated rectangular plates in air or in contact with water. The penetration of holes in the plates had a triangular pattern with P/D (pitch to diameter) 2.125, 2.500, 3.000 and 3.750. The plate was clamped along the plate edges by a number of bolts and nuts. The natural frequencies of the perforated plates in air were obtained by the analytical method based on the relation between the reference kinetic and maximum potential energies and compared with the experimental results. Good agreement between the results was found for the natural frequencies of the perforated plates in air. Additionally, it was empirically found that the natural frequencies of the perforated plate in air increase with an increase of P/D, on the other hand, the natural frequencies of the perforated plate in contact with water decrease with an increase of P/D.
Address
Kyeong-Hoon Jeong, Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Taejon 305-600, Korea Byung-Ki Ahn and Seong-Cheol Lee, Department of Mechanical Engineering, Chonbuk National University, Chonju, Chonbuk 560-756, Korea
Abstract
Four finite element (FE) models are examined to find the one that best estimates moment-rotation characteristics of top- and seat-angle with double web-angle connections. To efficiently simulate the real behavior of connections, finite element analyses are performed with following considerations: 1) all components of connection (beam, column, angles and bolts) are discretized by eight-node solid elements; 2) shapes of bolt shank, head, and nut are precisely taken into account in modeling; and 3) contact surface algorithm is applied as boundary condition. To improve accuracy in predicting moment-rotation behavior of a connection, bolt pretension is introduced before the corresponding connection moment being surcharged. The experimental results are used to investigate the applicability of FE method and to check the performance of three-parameter power model by making comparison among their moment-rotation behaviors and by assessment of deformation and stress distribution patterns at the final stage of loading. This research exposes two important features: (1) the FE method has tremendous potential for connection modeling for both monotonic and cyclic loading; and (2) the power model is able to predict moment-rotation characteristics of semi-rigid connections with acceptable accuracy.
Key Words
semi-rigid connection; moment-rotation behavior; connection stiffness and strength; monotonic loading; finite element method.
Address
N. Kishi, A. Ahmed and N. Yabuki, Department of Civil Engineering, Muroran Institute of Technology, Muroran 050-8585, Japan W.F. Chen, College of Engineering, University of Hawaii, Manoa, Honolulu, HI 96822, U.S.A.
Abstract
In this paper, an asymptotic two-scale method is developed for solving vibration problem of long periodic structures. Such eigenmodes appear as a slow modulations of a periodic one. For those, the present method splits the vibration problem into two small problems at each order. The first one is a periodic problem and is posed on a few basic cells. The second is an amplitude equation to be satisfied by the envelope of the eigenmode. In this way, one can avoid the discretisation of the whole structure. Applying the Floquet method, the boundary conditions of the global problem are determined for any order of the asymptotic expansions.
Address
E.M. Daya and M. Potier-Ferry, Laboratoire de Physique et Mecanique des Materiaux UMR CNRS 7554, Institut Superieur de Genie Mecanique et Productique Universite de Metz, Ile du Saulcy, 57045 Metz cedex 01, France
