Definition and updating of simplified models of joint stiffness

Abstract

a b s t r a c tThe objective of this work is to define a simple linear model of joints used in aeronautics and to update this model efficiently.Industrial designers usually resort to semi-empirical linear joint models to represent the behavior of the joints of a large aeronautical structure. Here, we propose to develop a one-dimensional linear joint model which is capable of representing the behavior of every joint of a large structure globally while enabling local nonlinear reanalysis of the most highly loaded joints. Work on nonlinear reanalysis is not considered in this paper.In order to solve the numerical difficulties encountered in some of modeling situations, an updating strategy based on the constitutive relation error is proposed. Since the updating efficiency is significantly affected by the ratios of the stiffnesses of the different parts of the model, the strategy consists in rigidifying some parts of the model in order to control the updating accuracy and the rate of convergence. The numerical results of a standard model and a rigidified model illustrate the updating improvements allowed by the strategy.

Partially open crack model for leakage pressure analysis of bolted metal-to-metal flange

“…Some of these studies have focused on the tightening process [36] and the bolt-up sequence of a flanged connection [37,53]. The stiffness of bolted joints was investigated in [54][55][56][57][58] and the bolt self-loosening was examined in [59][60][61]. Recent analyses of flanged joints have proposed FE simulations to investigate the contact pressure distributions between the two flange mating surfaces [2,10,62].…”

Goal-oriented updating of mechanical models using the adjoint framework

“…The gradient of F h (p) with respect to p i can be computed explicitly with low computational effort. Indeed, for the couple (U, V) solution of the constrained minimization problem (19) and with Λ = V − U, we have:…”

“…First introduced in [26,7,13,27,14] for dynamics models, this method was latter successfully used in many calibration applications including defects [11], uncertain measurements and behaviors [29,17], or corrupted measurements [1]. Recent applications of the method dealt with the updating of models used in bolted assemblies [19], or association with PGD reduced models to deal with realtime calibration in machining processes [10]. The use of the CRE presents interesting advantages; it has excellent capacities to localize structural defects spatially, it is very robust with respect to noisy measurements, and it has good convexity properties.…”

Inverse Identification of Virtual Material Parameters Using Surface Response Methodology

“…At this time, finite element analysis (FEA) technique including modeling and simulation is one of the most commonly used methods for studying the dynamic characteristics of mechanical structures [6]. Several common methods in FEA involve the use of beam element [7], Iwan's model [8,9], and spring-damper system [10,11]. Among these methods, the use of spring-damper system for describing the characteristics of joint interface is the preferred approach so far.…”