Characterization of structural connections using free and forced response test data

The accurate prediction of system dynamic response often has been limited by deficiencies in existing capabilities to characterize connections adequately. Connections between structural components often are complex mechanically, and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic preditions. A procedure for identifying physical connection properties from free and forced response test data is developed, then verified utilizing a system having both a linear and nonlinear connection. Connection properties are computed in terms of physical parameters so that the physical characteristics of the connections can better be understood, in addition to providing improved input for the system model. The identification procedure is applicable to multi-degree of freedom systems, and does not require that the test data be measured directly at the connection locations

Identification of structural interface characteristics using component mode synthesis

The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig are presented

A global approach for the identification of structural connection properties

A general procedure is developed for identifying properties of structural joints. The procedure, which uses experimental response data, is considered general because it is applicable to any size or type of structural system. The present procedure, which identifies characteristics such as damping and stiffness, accommodates both linear and nonlinear joint properties and may process test data measured at arbitrary stations on the structural system. The method identifies joint characteristics by performing a global fit between predicted and measured data. It overcomes limitations of previous methods in that it can better deal with parameter-dependent constraints (e.g., gaps). The method is demonstrated with a simplified model of a bladed disk assembly having friction damping and mistuning

Metallic Slit-Plate Dampers: Damage Evaluation with Metal Magnetic Memory Technique and Application to Structures with Rocking Columns

The authors thank the PREDITEST Company, from the Czech Republic, and in particular Svoboda, for support in MMM equipment, measurements, and scientific discussionsInelastic deformation of metallic materials is one of the most effective mechanisms for the dissipation of energy input to a structure by an earthquake. Metallic dampers are special devices that resort to this source of energy dissipation, proving to be a cost-efficient solution for the seismic protection of structures. Two important issues arise when implementing metallic dampers in real structures: (1) Inelastic deformations cause damage that must be quantified after an earthquake to decide upon their eventual replacement; (2) dampers must possess an energy dissipation capacity large enough to endure severe earthquakes. This paper focuses on a particular type of metallic damper consisting of slit-plates made of stainless steel, applied to reinforced concrete frames with rocking columns at the first story. In particular, a new damage index based on the metallic magnetic memory (MMM) method is proposed and validated experimentally to quantify the damage of slit plate dampers subjected to cyclic loadings. Further, the seismic response of a frame with rocking columns that incorporate the damper is obtained to demonstrate that it can endure severe earthquakes without failing, and to emphasize the relevance of the proposed MMM damage index that would make its replacement after a severe earthquake unnecessary.This research was funded by Consejería de Economia, Innovación, Ciencia y Empleo, Junta de Andalucía, grant number TEP-02429, by Ministerio de Economía, Industria y Competitividad, Gobierno de España, grant number BIA2017 88814 R, and received funds from the European Union (Fonds Européen de Dévelopment Régional). The APC was funded by Ministerio de Economía, Industria y Competitividad, Gobierno de España, grant number BIA2017 88814 R

Approximate decoupling of torsional and translation seismic response considering diaphragm flexibility

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Implementation of field strain measurements for fatigue lifetime evaluation

Cover title.; "June 2002."; Includes bibliographical references (leaf 77).; Final report.; Performed in cooperation with Ohio Dept. of Transportation and the Federal Highway Administration under state job no. 14745(0); Harvested from the web on 3/28/06An accurate estimate of the remaining fatigue lifetime of a bridge is needed in bridge management systems that are used to make cost effective decisions regarding inspection, maintenance, repair, rehabilitation and replacement of existing bridges. The estimation of remaining life is also crucial for assessing permit-vehicle policy and determining the effects of permitting a certain class of overloaded vehicles to use the highways, and can be used to assess legislative policies such as permissible truck weights. The fatigue-life approach can also be applied in the design of new bridges.An accurate estimate of the remaining fatigue lifetime of a bridge is needed in bridge management systems that are used to make cost effective decisions regarding inspection, maintenance, repair, rehabilitation and replacement of existing bridges. The estimation of remaining life is also crucial for assessing permit-vehicle policy and determining the effects of permitting a certain class of overloaded vehicles to use the highways, and can be used to assess legislative policies such as permissible truck weights. The fatigue-life approach can also be applied in the design of new bridges