A Bayesian Inference-Based Approach to Empirical Training of Strongly Coupled Constituent Models

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
G. S. Flynn ◽  
E. Chodora ◽  
S. Atamturktur ◽  
D. A. Brown
Keyword(s):  
Finite Element ◽  
Bayesian Inference ◽  
Finite Element Model ◽  
Numerical Models ◽  
Element Model ◽  
Numerical Representation ◽  
Strongly Coupled ◽  
Practical Applications ◽  
Novel Approach ◽  
Integral Effect

Abstract Partitioned analysis enables numerical representation of complex systems through the coupling of smaller, simpler constituent models, each representing a different phenomenon, domain, scale, or functional component. Through this coupling, inputs and outputs of constituent models are exchanged in an iterative manner until a converged solution satisfies all constituents. In practical applications, numerical models may not be available for all constituents due to lack of understanding of the behavior of a constituent and the inability to conduct separate-effect experiments to investigate the behavior of the constituent in an isolated manner. In such cases, empirical representations of missing constituents have the opportunity to be inferred using integral-effect experiments, which capture the behavior of the system as a whole. Herein, we propose a Bayesian inference-based approach to estimate missing constituent models from available integral-effect experiments. Significance of this novel approach is demonstrated through the inference of a material plasticity constituent integrated with a finite element model to enable efficient multiscale elasto-plastic simulations.

Identification of cracks in an Euler–Bernoulli beam using Bayesian inference and closed-form solution of vibration modes

2020 ◽  
pp. 146442072096971
Author(s):  
Tianyu Wang ◽  
Mohammad Noori ◽  
Wael A. Altabey
Keyword(s):  
Finite Element ◽  
Bayesian Inference ◽  
Finite Element Model ◽  
Crack Detection ◽  
Closed Form Solution ◽  
Element Model ◽  
Form Solution ◽  
Vibration Modes ◽  
Vibration Data ◽  
The Finite Element Model

Over the past two decades, extensive research has been carried out in the field of structural health monitoring for damage detection in structural systems. Some crack detection methods are based on the finite element model of a beam and use vibration data are developed. These methods identify the crack by updating of the finite element model according to the vibration data of structure. This paper proposes a novel method for crack detection in Euler–Bernoulli beams based on the closed-form solution of mode shapes using Bayesian inference. The expression of vibration modes is derived analytically with the crack parameters as unknown variables. Subsequently, the Bayesian inference is used to obtain the probability density function of crack parameters and to evaluate the uncertainty of the modes. Finally, the method is applied to a series of numerical examples, including a beam with a single-crack and multi-cracks, to verify the effectiveness of this method.

scholarly journals Vibration-based Bayesian model updating of civil engineering structures applying Gaussian process metamodel

2019 ◽  
Vol 22 (16) ◽  
pp. 3487-3502
Author(s):  
Hossein Moravej ◽  
Tommy HT Chan ◽  
Khac-Duy Nguyen ◽  
Andre Jesus
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bayesian Approach ◽  
Model Updating ◽  
Numerical Models ◽  
Element Model ◽  
The Body ◽  
Structural Safety ◽  
Discrepancy Function ◽  
The Finite Element Model

Structural health monitoring plays a significant role in providing information regarding the performance of structures throughout their life spans. However, information that is directly extracted from monitored data is usually susceptible to uncertainties and not reliable enough to be used for structural investigations. Finite element model updating is an accredited framework that reliably identifies structural behavior. Recently, the modular Bayesian approach has emerged as a probabilistic technique in calibrating the finite element model of structures and comprehensively addressing uncertainties. However, few studies have investigated its performance on real structures. In this article, modular Bayesian approach is applied to calibrate the finite element model of a lab-scaled concrete box girder bridge. This study is the first to use the modular Bayesian approach to update the initial finite element model of a real structure for two states—undamaged and damaged conditions—in which the damaged state represents changes in structural parameters as a result of aging or overloading. The application of the modular Bayesian approach in the two states provides an opportunity to examine the performance of the approach with observed evidence. A discrepancy function is used to identify the deviation between the outputs of the experimental and numerical models. To alleviate computational burden, the numerical model and the model discrepancy function are replaced by Gaussian processes. Results indicate a significant reduction in the stiffness of concrete in the damaged state, which is identical to cracks observed on the body of the structure. The discrepancy function reaches satisfying ranges in both states, which implies that the properties of the structure are predicted accurately. Consequently, the proposed methodology contributes to a more reliable judgment about structural safety.

scholarly journals Numerical Investigation on the Role of Mechanical Factors Contributing to Globe Flattening in States of Elevated Intracranial Pressure

Life ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 316
Author(s):  
Jafar A. Mehr ◽  
Heather E. Moss ◽  
Hamed Hatami-Marbini
Keyword(s):  
Finite Element ◽  
Intracranial Pressure ◽  
Finite Element Model ◽  
Material Properties ◽  
Numerical Study ◽  
Numerical Models ◽  
Element Model ◽  
Elevated Intracranial Pressure ◽  
Mr Images ◽  
Mechanical Factors

Flattening of the posterior eye globe in the magnetic resonance (MR) images is a sign associated with elevated intracranial pressure (ICP), often seen in people with idiopathic intracranial hypertension (IIH). The exact underlying mechanisms of globe flattening (GF) are not fully known but mechanical factors are believed to play a role. In the present study, we investigated the effects of material properties and pressure loads on GF. For this purpose, we used a generic finite element model to investigate the deformation of the posterior eyeball. The degree of GF in numerical models and the significance of different mechanical factors on GF were characterized using an automated angle-slope technique and a statistical measure. From the numerical models, we found that ICP had the most important role in GF. We also showed that the angle-slope graphs pertaining to MR images from five people with high ICP can be represented numerically by manipulating the parameters of the finite element model. This numerical study suggests that GF observed in IIH patients can be accounted for by the forces caused by elevation of ICP from its normal level, while material properties of ocular tissues, such as sclera (SC), peripapillary sclera (PSC), and optic nerve (ON), would impact its severity.

Initial testing of a two-dimensional finite element model for floodplain inundation

1994 ◽  
Vol 444 (1920) ◽  
pp. 149-159 ◽  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Models ◽  
Element Model ◽  
Two Dimensional ◽  
Catchment Scale ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Floodplain Inundation ◽  
River Reach

Current research needs for the two-dimensional finite element simulation of river flood flows are discussed. It is suggested that there is a need to test such numerical models to assess critically their ability to simulate river floodplain inundation. Initial tests are undertaken within the context of an application of a two-dimensional finite element model to a 14 km river reach in the U. K. Model behaviour is examined and shown to be stable, accurate and consistent with theoretical expectations and the need for improved data acquisition for model testing is highlighted. On the basis of these numerical experiments a number of implications for current catchment scale integrated hydrological modelling are discussed.

scholarly journals A Pneumatic Novel Combined Soft Robotic Gripper with High Load Capacity and Large Grasping Range

Actuators ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Dan Wang ◽  
Xiaojun Wu ◽  
Jinhua Zhang ◽  
Yangyang Du
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Material Properties ◽  
Load Capacity ◽  
Element Model ◽  
High Load ◽  
Minimum Diameter ◽  
Practical Applications ◽  
Soft Actuator ◽  
High Load Capacity

Pneumatic soft grippers have been widely studied. However, the structures and material properties of existing pneumatic soft grippers limit their load capacity and manipulation range. In this article, inspired by sea lampreys, we present a pneumatic novel combined soft gripper to achieve a high load capacity and a large grasping range. This soft gripper consists of a cylindrical soft actuator and a detachable sucker. Three internal air chambers of the cylindrical soft actuator are inflated, which enables them to hold objects. Under vacuum pressure, the cylindrical soft actuator and the detachable sucker can both adsorb objects. A finite element model was constructed to simulate three inflation chambers for predicting the grasping range of the cylindrical soft actuator. The validity of the finite element model was established by an experiment. The mechanism of holding force and adsorption force were analyzed. Several groups of experiments were conducted to determine adsorption range, holding force, and adsorption force. In addition, practical applications further indicated that the novel combined soft gripper has a high load capacity (10.85 kg) at a low pressure (16 kPa) and a large grasping range (minimum diameter of the object: d = 6 mm), being able to lift a variety of objects with different weights, material properties, and shapes.

scholarly journals Numerical Simulations of Dynamic Behavior of Polyurea Toughened Steel Plates under Impact Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chien-Chung Chen ◽  
Daniel G. Linzell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Impact Loading ◽  
Numerical Models ◽  
Model Development ◽  
Time History ◽  
Element Model ◽  
Steel Plates ◽  
Numerical Work

The objective of the work discussed herein is to develop a nonlinear 3D finite element model to simulate dynamic behavior of polyurea toughened steel plates under impact loading. Experimental and numerical work related to model development are presented. Material properties are incorporated into numerical models to account for strain-rate effects on the dynamic behavior of polyurea and steel. One bare steel plate and four polyurea toughened steel plates were tested under impact loading using a pendulum impact device. Displacement time-history data from experimental work was used to validate the numerical models. Details on material model construction, finite element model development, and model validation are presented and discussed. Results indicate that the developed numerical models can reasonably predict dynamic response of polyurea toughened steel plates under impact loading.

Feedback Control Applied to Finite Element Models of Morphing Structures

2014 ◽  
Author(s):  
Christopher Bertagne ◽  
Peyman Moghadas ◽  
Richard Malak ◽  
Darren Hartl
Keyword(s):  
Finite Element ◽  
Feedback Control ◽  
Finite Element Model ◽  
Numerical Models ◽  
Element Model ◽  
High Fidelity ◽  
Element Analysis ◽  
Wide Range ◽  
Flexible Framework ◽  
The Finite Element Model

This paper demonstrates a framework for integrating full feedback control with a high-fidelity finite element model in order to simulate control of morphing structures. Most of the previous finite element simulations involving control of morphing structures consider the effects of the controller, but do not incorporate true feedback control. Additionally, when feedback control is considered, numerical models other than finite element analysis are used. Thus, a trade-off must be made between a high-fidelity model and consideration of feedback control. In this work, these aspects are unified to create a tool that can simulate real-time feedback control of a finite element model. The framework itself consists of two components: the finite element model and the controller. The finite element model must be capable of varying external loads as the solution evolves in time. In this paper, the finite element model is implemented in ABAQUS. The controller component is written in Python. In order to ensure the framework is suitable for a wide range of applications, no assumptions are made regarding the natures of the finite element model or the control architecture. Additionally, the components are designed to be modular. For example, simulating different controller architectures does not require alteration of the finite element model. The result is a highly flexible framework that is particularly well-suited for validating and demonstrating controllers on high-fidelity models.

scholarly journals Numerical Simulation of Steel Reinforced Concrete (SRC) Joints

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 131 ◽  
Author(s):  
Isaac Montava ◽  
Ramon Irles ◽  
Jorge Segura ◽  
Jose Gadea ◽  
Ernesto Juliá
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Numerical Models ◽  
Experimental Tests ◽  
Element Model ◽  
Reinforced Concrete Beams ◽  
Plastic Behavior ◽  
Steel Reinforced Concrete ◽  
Concrete Joints

This paper presents a three-dimensional finite element model to confirm experimental tests carried out on steel reinforced concrete joints. The nonlinear behavior of this concrete is simulated, along with its reduced capability to resist large displacements in compression. The aim was to obtain the plastic behavior of reinforced concrete beams with a numerical model in the same way as obtained experimentally, in which the reduction of strength in the post-critical stage was considered to simulate behavior until structures collapsed. To do this, a nonlinear calculation was necessary to simulate the behavior of each material. Three numerical models provide a moment–curvature graph of the cross-section until collapse. Simulation of the structural elements is a powerful tool that avoids having to carry out expensive experimental tests. From the experimental results a finite element model is simulated for the non-linear analysis of steel reinforced concrete joints. It is possible to simulate the decreasing stress behavior of the concrete until reaching considerable displacement. A new procedure is discussed to capture the moment-curvature diagram. This diagram can be used in a simplified frame analysis, considering post-critical behavior for future research.

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