Title

Constitutive Modeling of Nonlinear Damping Materials

Description

Many of the damping materials that have been developed recently are used under transient conditions at levels of strain where their response is highly nonlinear (e.g., to improve the seismic performance of buildings and other structures in earthquake-prone regions). Transient analysis of these nonlinear materials cannot be done using Fourier or other transform methods; real time analysis is needed. In this study these materials are treated as viscoelastic and their nonlinear constitutive relations are constructed in the time domain using internal variables to account for inelastic behavior and damage. This is an approach which is popular in modern constitutive theory and has many advantages. It leads to a formulation in terms of a system of first-order nonlinear ordinary differential (or differential-functional) equations, which is computationally convenient. Furthermore, if the analyst has physical insights into the micromechanical processes that are producing the inelastic deformation and damage, then the internal variable formulation provides a means for mathematically expressing this information in the structure of the constitutive relation. Some prototypes are constructed and employed to predict hysteresis loops.

Creator

Sackman, Jerome L.

Javid, Ahmad E.

Publisher

Wright-Patterson Air Force Base, OH : Wright Laboratory, Flight Dynamics Directorate, Air Force Systems Command

Date

1991

Format

1 online resource (15 pages) : ill.

Type

article

Abstract

Many of the damping materials that have been developed recently are used under transient conditions at levels of strain where their response is highly nonlinear (e.g., to improve the seismic performance of buildings and other structures in earthquake-prone regions). Transient analysis of these nonlinear materials cannot be done using Fourier or other transform methods; real time analysis is needed. In this study these materials are treated as viscoelastic and their nonlinear constitutive relations are constructed in the time domain using internal variables to account for inelastic behavior and damage. This is an approach which is popular in modern constitutive theory and has many advantages. It leads to a formulation in terms of a system of first-order nonlinear ordinary differential (or differential-functional) equations, which is computationally convenient. Furthermore, if the analyst has physical insights into the micromechanical processes that are producing the inelastic deformation and damage, then the internal variable formulation provides a means for mathematically expressing this information in the structure of the constitutive relation. Some prototypes are constructed and employed to predict hysteresis loops.

Date Issued

1991-08

Extent

15

Corporate Author

University of California at Berkeley

IBM Corporation

Laboratory

Wright Laboratory

Report Number

WL-TR-91-3078 Volume II, pages EBC-1 to EBC-15

DoD Project

2401

DoD Task

240104

Distribution Conflict

No

Photo Quality

Not Needed

Distribution Classification

1

Report Availability

Full text available

Index Abstract

Contrails only

Provenance

University of Colorado Colorado Springs, Kraemer Family Library

Identifier

ADA241312

Is Part Of

Proceedings of Damping '91: 13-15 February 1991 San Diego, California (EAA-1 through GBC-16)