A Remote Solitary Wave–based Technique for Monitoring Corrosion in Steel Structures: Numerical Analysis and Experimental Validation

2021 ◽  
Author(s):  
Hoda Jalali ◽  
Piervincenzo Rizzo
Keyword(s):  
Solitary Wave ◽  
Solitary Waves ◽  
Plate Thickness ◽  
Point Contact ◽  
Element Model ◽  
Contact Forces ◽  
Localized Corrosion ◽  
Spherical Particles ◽  
Corrosion Monitoring ◽  
Highly Nonlinear

Abstract A new corrosion monitoring technique based on the generation and propagation of highly nonlinear solitary waves in 1D granular crystals has been developed recently. In this method, a monoperiodic array of spherical particles, interacting via Hertzian contact forces, is in point contact with the structure or material to be inspected. The array is part of a wireless unit used to induce the wave in the chain and record the solitary waveform remotely. Compared to classical NDE techniques used for thickness monitoring, the developed method is low cost, portable, and simple. This study presents a numerical and an experimental investigation of the sensitivity of solitary waves to localized corrosion. In the experimental study, a corroding steel plate was monitored using solitary waves to examine the effect of corrosion in the plate on the solitary waves interacting with the plate. Furthermore, a discrete element model was coupled with a finite element model to numerically predict the effect of localized corrosion on the delay and the amplitude of the reflected solitary waves formed at the chain-plate interface. The plate was studied in both pristine and corroded conditions. Furthermore, the study investigated customizing the granular chain design to achieve solitary wave-based sensors that can be used in high-temperature environments with maximum sensitivity to corrosion. The numerical results were in good agreement with experimental results and showed that the reflected solitary waves are affected by the presence and the propagation of corrosion in the plate. It was also shown that the sensitivity of the method increases for thinner plates or when the depth of corrosion exceeds half of the plate thickness.

Numerical Analysis and Experimental Validation of an Nondestructive Evaluation Method to Measure Stress in Rails

2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Amir Nasrollahi ◽  
Piervincenzo Rizzo
Keyword(s):  
Nondestructive Evaluation ◽  
Solitary Waves ◽  
Evaluation System ◽  
Experimental Validation ◽  
Axial Stress ◽  
Point Contact ◽  
Spherical Particles ◽  
Particle Model ◽  
Numerical Predictions ◽  
Highly Nonlinear

This article presents a numerical formulation and the experimental validation of the dynamic interaction between highly nonlinear solitary waves generated along a mono-periodic array of spherical particles and rails in a point contact with the array. A general finite element model of rails was developed and coupled to a discrete particle model able to predict the propagation of the solitary waves along a L-shaped array located perpendicular and in contact with the web of the rail. The models were validated experimentally by testing a 0.9-m long and a 2.4-m long rail segments subjected to compressive load. The scope of the study was the development of a new nondestructive evaluation technique able to estimate the stress in continuous welded rails and eventually to infer the temperature at which the longitudinal stress in the rail is zero. The numerical findings presented in this article demonstrate that certain features, such as the amplitude and time of flight, of the solitary waves are affected by the axial stress. The experimental results validated the numerical predictions and warrant the validation of the nondestructive evaluation system against real rails.

Finite Element Analysis of Large-Size Yaw Bearings with Supporting Structure in Wind Turbine

2014 ◽  
Vol 672-674 ◽  
pp. 1550-1553
Author(s):  
Zhen Guo Shang ◽  
Zhong Chao Ma ◽  
Zhen Sheng Sun
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Point Contact ◽  
Element Model ◽  
Contact Forces ◽  
Element Analysis ◽  
Supporting Structure ◽  
Rolling Elements ◽  
Yaw Bearing ◽  
Compression Springs

A procedure for obtaining the load distribution in a four point contact wind turbine yaw bearing considering the effect of the structure’s elasticity is presented. The inhomogeneous stiffness of the supporting structures creates a variation in the results obtained with a rigid model. A finite element model substituting the rolling elements with nonlinear compression springs has been built to evaluate the effect of the supporting structure elasticity on the contact forces between the rolling elements and the raceways.

Design of Four Contact-Point Slewing Bearing With a New Load Distribution Procedure to Account for Structural Stiffness

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Mireia Olave ◽  
Xabier Sagartzazu ◽  
Jorge Damian ◽  
Alberto Serna
Keyword(s):  
Load Distribution ◽  
Contact Point ◽  
Element Model ◽  
Contact Forces ◽  
Elastic Model ◽  
Slewing Bearing ◽  
Extreme Loads ◽  
Highly Nonlinear ◽  
Rolling Elements ◽  
Bearing Rings

This paper proposes a procedure for obtaining the load distribution in a four contact-point slewing bearing considering the effect of the structure’s elasticity. The uneven stiffness of the rings and the supporting structures creates a variation with respect to the results obtained with a rigid model. It is necessary to evaluate the effect of the elasticity on the increase in the contact forces in order to be able to design the slewing bearing and the structures involved in the connection. Depending on the shape of the structures, the contact force value obtained on the most loaded rolling element is different. The evaluation of this maximum force at extreme loads is essential to design the structures joined to the bearing rings. The new elastic model presented in this paper is highly nonlinear so iterative loops are needed in order to obtain a satisfactory solution. At the same time a finite element model (FEM) has been created for the global model, having also represented the rolling elements and their contact with the raceways. The results obtained using the FEM have been correlated with the results of the new procedure.

Cure Monitoring of Adhesive for Composite/Metal Bonded Structure Based on Highly Nonlinear Solitary Waves

2019 ◽  
Author(s):  
Wu Bin ◽  
Li Mingzhi ◽  
Liu Xiucheng ◽  
Wang Heying ◽  
He Cunfu ◽  
...  
Keyword(s):  
Solitary Wave ◽  
Solitary Waves ◽  
Curing Process ◽  
One Dimensional ◽  
Granular Chain ◽  
Highly Nonlinear ◽  
Highly Nonlinear Solitary Waves ◽  
Simulation Results ◽  
The One ◽  
Nonlinear Solitary Waves

Abstract In this paper, a nondestructive evaluation technique based on highly nonlinear solitary waves (HNSWs) is proposed to monitor the curing process of adhesive for composite/metal bonded structure. HNSWs are mechanical waves with high energy intensity and non-distortive nature which can form and propagate in a nonlinear system, such as a one-dimensional granular chain. In the present study, a finite element model of the one-dimensional granular chain is established with the commercial software Abaqus, to study the reflection behavior of HNSWs at the interface between the particle at the end of chain and the sample. The simulation results show that the time of flight (TOF) of the primary reflected solitary wave decreases with the stiffness of the sample increases, and the amplitude ratio (AR) between the primary reflected solitary wave and the incident solitary wave increases. An HNSWs transducer based on the one-dimensional granular chain is designed and fabricated. The relationship between the characteristic parameters of the primary reflected solitary wave (TOF and AR) and the curing time of adhesive for a composite/metal bonded structure is experimentally investigated. The experiment results suggest that the TOF decreases and the AR increases as the epoxy cures. The experimental results are in good agreement with the simulation results. This study provides a new characterization method for monitoring the curing process of adhesive for composite/metal bonded structure.

Highly Nonlinear Solitary Waves to Estimate Orientation and Degree of Anisotropy in Rocks

2021 ◽  
Vol 79 (10) ◽  
pp. 991-1004
Author(s):  
Hoda Jalali ◽  
Yuhui Zeng ◽  
Piervincenzo Rizzo ◽  
Andrew Bunger
Keyword(s):  
Solitary Waves ◽  
Numerical Models ◽  
Spherical Particles ◽  
Highly Nonlinear ◽  
Degree Of Anisotropy ◽  
Highly Nonlinear Solitary Waves ◽  
Rock Interface ◽  
Nondestructive Identification ◽  
Nonlinear Solitary Waves

This paper delves into the use of highly nonlinear solitary waves for the nondestructive identification and characterization of anisotropy in rocks. The nondestructive testing approach proposed expands upon a technique developed recently by some of the authors for the nondestructive characterization of engineering materials and structures. The technique uses the characteristics of solitary waves propagating in a periodic array of spherical particles in contact with the rock to be characterized. The features of the waves that bounce off the chain rock interface are used to infer some properties of the geomaterial under consideration. Numerical models and experimental validation were conducted to explore the feasibility of the method and to standardize the methodology for future widespread applications.

scholarly journals Highly Nonlinear Solitary Waves for the Assessment of Dental Implant Mobility

2012 ◽  
Vol 80 (1) ◽  
Author(s):  
Bruk Berhanu ◽  
Piervincenzo Rizzo ◽  
Mark Ochs
Keyword(s):  
Dental Implant ◽  
Solitary Waves ◽  
Spherical Particles ◽  
Noninvasive Technique ◽  
Acid Bath ◽  
Mechanical Waves ◽  
Highly Nonlinear ◽  
Highly Nonlinear Solitary Waves ◽  
The Stability ◽  
Nonlinear Solitary Waves

In this paper we present a noninvasive technique based on the propagation of highly nonlinear solitary waves (HNSWs) to monitor the stability of dental implants. HNSWs are nondispersive mechanical waves that can form and travel in highly nonlinear systems, such as one-dimensional chains of spherical particles. The technique is based on the hypothesis that the mobility of a dental implant affects certain characteristics of the HNSWs reflected at the interface between a crystal-based transducer and the implant. To validate the research hypothesis we performed two experiments: first we observed the hydration of commercial plaster to simulate at large the osseointegration process that occurs in the oral connective tissue once a dental-endosteal threaded implant is surgically inserted; then, we monitored the decalcification of treated bovine bones immersed in an acid bath to simulate the inverse of the osseointegration process. In both series, we found a good correlation between certain characteristics of the HNSWs and the stiffness of the material under testing.

Modeling of Load Distribution in Large-Size Wind Turbine Blade Bearings

2011 ◽  
Vol 199-200 ◽  
pp. 1410-1413 ◽  
Author(s):  
Zhen Guo Shang ◽  
Tian Yi Gao ◽  
Hua Wang
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Load Distribution ◽  
Point Contact ◽  
Element Model ◽  
Wind Turbine Blade ◽  
Contact Forces ◽  
Large Size ◽  
Rolling Elements ◽  
Rigid Model

This paper proposes a procedure for obtaining the load distribution in a four point contact wind turbine blade bearing considering the effect of the structure’s elasticity. The uneven stiffness of the rings and the supporting structures creates a variation with respect to the results obtained with a rigid model. It is necessary to evaluate the effect of the elasticity on the increase in the contact forces in order to be able to design the wind turbine blade bearing and the structures involved in the connection. A finite element model (FEM) has been created for the global model, having also represented the rolling elements and their contact with the raceways. The results obtained using the FEM have been compared with the traditional Hertz contact results.

scholarly journals Wireless Module for Nondestructive Testing/Structural Health Monitoring Applications Based on Solitary Waves

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3016 ◽  
Author(s):  
Ritesh Misra ◽  
Hoda Jalali ◽  
Samuel J. Dickerson ◽  
Piervincenzo Rizzo
Keyword(s):  
Structural Health Monitoring ◽  
Solitary Waves ◽  
Health Monitoring ◽  
Hertzian Contact ◽  
Spherical Particles ◽  
Structural Health ◽  
Mechanical Waves ◽  
Highly Nonlinear ◽  
Monitoring Applications ◽  
Wireless Module

In recent years, there has been an increasing interest in the use of highly nonlinear solitary waves (HNSWs) for nondestructive evaluation and structural health monitoring applications. HNSWs are mechanical waves that can form and travel in highly nonlinear systems, such as granular particles in Hertzian contact. The easiest setup consists of a built-in transducer in drypoint contact with the structure or material to be inspected/monitored. The transducer is made of a monoperiodic array of spherical particles that enables the excitation and detection of the solitary waves. The transducer is wired to a data acquisition system that controls the functionality of the transducer and stores the time series for post-processing. In this paper, the design and testing of a wireless unit that enables the remote control of a transducer without the need to connect it to sophisticated test equipment are presented. Comparative tests and analyses between the measurements obtained with the newly designed wireless unit and the conventional wired configuration are provided. The results are corroborated by an analytical model that predicts the dynamic interaction between solitary waves and materials with different modulus. The advantages and limitations of the proposed wireless platform are given along with some suggestions for future developments.

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