Monitoring of pin connection loosening using eletromechanical impedance: Numerical simulation with experimental verification

2018 ◽  
Vol 29 (9) ◽  
pp. 1964-1973 ◽  
Author(s):  
Shuli Fan ◽  
Weijie Li ◽  
Qingzhao Kong ◽  
Qian Feng ◽  
Gangbing Song
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Lead Zirconate Titanate ◽  
Numerical Study ◽  
Element Model ◽  
Impedance Method ◽  
Experimental Investigations ◽  
Detection Accuracy ◽  
Practical Applications ◽  
Electromechanical Impedance

Pin connection, as an important structural connection mechanism, is widely used in various structures, especially spatial structures. In this article, numerical and experimental investigations are performed for monitoring the loosening of pin-connected structures using the electromechanical impedance technique. For this purpose, a finite element model for a pin-connected structure considering the contact interfaces between the pin and the support base is proposed to study the effect of pin connection loosening on the electromechanical impedance signatures. A multi-physics analysis is conducted to simulate the electromechanical behavior of lead zirconate titanate transducers bonded on the pin head and the steel base. The relationship between the force applied on the pin connection and the variation in electromechanical impedance signatures is established. Experiments are carried out to verify the accuracy of the proposed finite element model. The results show that the changes in the electromechanical impedance signatures consist of frequency shifts and peak splitting. The contact condition of the pin connection can be assessed by observing the changes in the electromechanical impedance signatures. The location of the piezoelectric patch has significant effect on the sensitivity of the electromechanical impedance signatures. The numerical study in this research helps to optimize the design of sensor placement and improve the detection accuracy of the electromechanical impedance method in practical applications of detecting the loosening of pin-connected structures.

scholarly journals Modeling inflatable fabric with undevelopable surfaces by motion folding method

2019 ◽  
Vol 14 ◽  
pp. 155892501988640
Author(s):  
Xiao-Shun Zhao ◽  
He Jia ◽  
Zhihong Sun ◽  
Li Yu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Study ◽  
Technical Problem ◽  
Three Dimensional ◽  
Element Model ◽  
Model Errors ◽  
Folding Model ◽  
Study Results ◽  
The Stability

At present, most space inflatable structures are composed of flexible inflatable fabrics with complex undevelopable surfaces. It is difficult to establish a multi-dimensional folding model for this type of structure. To solve this key technical problem, the motion folding method is proposed in this study. First, a finite element model with an original three-dimensional surface was flattened with a fluid structure interaction algorithm. Second, the flattened surface was folded based on the prescribed motion of the node groups, and the final folding model was obtained. The fold modeling process of this methodology was consistent with the actual folding processes. Because the mapping relationship between the original finite element model and the final folding model was unchanged, the initial stress was used to modify the model errors during folding process of motion folding method. The folding model of an inflatable aerodynamic decelerator, which could not be established using existing folding methods, was established by using motion folding method. The folding model of the inflatable aerodynamic decelerator showed that the motion folding method could achieve multi-dimensional folding and a high spatial compression rate. The stability and regularity of the inflatable aerodynamic decelerator numerical inflation process and the consistency of the inflated and design shapes indicated the reliability, applicability, and feasibility of the motion folding method. The study results could provide a reference for modeling complex inflatable fabrics and promote the numerical study of inflatable fabrics.

Modelling High Velocity Impact on Aluminium Alloy 7075-T6 under Axial Pretension

2014 ◽  
Vol 629 ◽  
pp. 498-502 ◽  
Author(s):  
K.A. Kamarudin ◽  
Al Emran Ismail
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Aluminium Alloy ◽  
High Velocity ◽  
Numerical Study ◽  
Element Model ◽  
Ballistic Limit ◽  
High Velocity Impact ◽  
Velocity Impact

This paper explains the utilisation of finite element model to analyse the ballistic limit of aluminium alloy 7075-T6 impacted by 8.33 g with 12.5 mm radius rigid spherical projectiles. This numerical study was compared with the results obtained experimentally. During impact, the targets were subjected to either non- or uniaxial- pretension and the projectile travelled horizontally to the target. It was observed that pretensioned targets were more vulnerable, which reduced the ballistic limit. The existence of harmful failures owing to pretension impact was ascertained and compared with the non-pretension targets.

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.

scholarly journals Updating Finite Element Model of a Wind Turbine Blade Section Using Experimental Modal Analysis Results

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Marcin Luczak ◽  
Simone Manzato ◽  
Bart Peeters ◽  
Kim Branner ◽  
Peter Berring ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Numerical Study ◽  
Element Model ◽  
Full Scale ◽  
Wind Turbine Blade ◽  
Model Parameters ◽  
Blade Section

This paper presents selected results and aspects of the multidisciplinary and interdisciplinary research oriented for the experimental and numerical study of the structural dynamics of a bend-twist coupled full scale section of a wind turbine blade structure. The main goal of the conducted research is to validate finite element model of the modified wind turbine blade section mounted in the flexible support structure accordingly to the experimental results. Bend-twist coupling was implemented by adding angled unidirectional layers on the suction and pressure side of the blade. Dynamic test and simulations were performed on a section of a full scale wind turbine blade provided by Vestas Wind Systems A/S. The numerical results are compared to the experimental measurements and the discrepancies are assessed by natural frequency difference and modal assurance criterion. Based on sensitivity analysis, set of model parameters was selected for the model updating process. Design of experiment and response surface method was implemented to find values of model parameters yielding results closest to the experimental. The updated finite element model is producing results more consistent with the measurement outcomes.

Numerical Simulation of Rotational Behavior of Bolted Glulam Beam-to-Column Connections with Slotted-In Steel Plates

2016 ◽  
Vol 858 ◽  
pp. 22-28 ◽  
Author(s):  
Ming Qian Wang ◽  
Xiao Bin Song ◽  
Xiang Lin Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Evolution ◽  
Numerical Study ◽  
Material Model ◽  
Element Model ◽  
Rotational Behavior ◽  
Failure Behavior ◽  
Glulam Beam ◽  
Numerical Predictions

This paper presents the results of a numerical study on rotational behavior of bolted glulam beam-to-column connections. Since wood often exhibited complex failure behavior under different loading states, a three dimensional anisotropic damage analysis model of wood was initially developed based on continuum damage mechanics theory for progressive failure analysis of wood. The damage model basically consisted of two ingredients: the failure criterion proposed by Sandhaas was chosen to capture the damage onset; three independent damage variables were adopted to control the ductile and brittle damage evolution process of wood. This material model was implemented in a commercial available finite element method based code using a user-material subroutine. Finite element model of bolted connection coupled with the proposed material model was established to further investigate the failure modes and moment resistance of such connections. It was found that the damage evolution progress was very similar to the crack development from experimental tests. By comparing the experimental results and numerical predictions, a fair agreement of the initial stiffness and moment resistance was found with modeling error less than 3%, which implied that the finite element model was suitable to simulate the rotational behavior of such connections. This research could provide the reference for the design of bolted glulam connections in heavy timber structures.

scholarly journals Investigating pipeline–soil interaction under axial–lateral relative movements in sand

2011 ◽  
Vol 48 (11) ◽  
pp. 1683-1695 ◽  
Author(s):  
Nasser Daiyan ◽  
Shawn Kenny ◽  
Ryan Phillips ◽  
Radu Popescu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Lateral Interaction ◽  
Test Bed ◽  
Dense Sand ◽  
Centrifuge Tests ◽  
Soil Loading

This paper presents results from an experimental and numerical study on the axial–lateral interaction of pipes with dense sand. A series of centrifuge tests were conducted, with a rigid pipeline displaced in the horizontal plane in a cohesionless test bed. The relative pipe–soil interaction included axial, lateral, and oblique loading events. A three-dimensional continuum finite element model was developed using ABAQUS/Standard ( Hibbitt et al. 2005 ) software. The numerical model was calibrated against experimental results. A parametric study was conducted, using the calibrated finite element model to extend the investigations. The ultimate axial and lateral soil loading was found to be dependent on the angle of attack for relative movement between the pipe and soil. Two different failure mechanisms were observed for axial–lateral pipeline–soil interaction. This study confirms and improves on a two-part failure criterion that accounts for axial–lateral coupling during oblique soil loading events on buried pipelines.

Sign in / Sign up

Export Citation Format

Share Document