Article
Chemistry, Analytical
Daniele Oboe, Luca Colombo, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is gaining attention for shape sensing due to its independence from material properties and external load. Proper definition of model geometry, boundary conditions, and optimized sensor networks to acquire strain field are required for complex structures. A simplified iFEM model with reduced geometrical complexity and tuned boundary conditions is proposed to handle structures with partial sensor application, showing effectiveness in aeronautical structures with experimentally acquired strain measurements.
Article
Engineering, Electrical & Electronic
Mohammad Amin Abdollahzadeh, Muhammed Yavuz Belur, Muhammed Fatih Basoglu, Adnan Kefal
Summary: This study aims to verify the applicability of the quadrilateral iFEM plate/shell element, iFEM-iQS4, for shape sensing of 2D beam-like structures by comparing it with the recently developed inverse beam element iFEM-iBeam3. It also demonstrates the high efficiency and accuracy of iFEM-iQS4 analysis for 3D shape sensing of beam-like structures with different cross sections.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Engineering, Marine
Mingyang Li, Yildirim Dirik, Erkan Oterkus, Selda Oterkus
Summary: This study presents the shape sensing of a blade of the NREL 5 MW offshore wind turbine using the inverse Finite Element Method (iFEM) under real loading conditions. Aerodynamic forces are calculated based on the Blade Element Momentum Theory (BEMT). The accuracy of the iFEM analysis is tested by comparing the results with full sensors and reduced sensors to the reference Finite Element Method (FEM) analysis. Practical distribution of iFEM elements with sensors is explored and the effects of different wind velocities are investigated for more practical analysis. Based on numerical results, it is concluded that iFEM is a suitable technique for shape sensing of offshore wind turbines.
Article
Engineering, Electrical & Electronic
Shengtao Niu, Yanhao Guo, Hong Bao, Guojun Leng
Summary: This study presents an enhanced inverse finite-element method (iFEM) for reconstructing the deformation of homogeneity structures, including thin to thick plate models. The method establishes a clear relation between the structural mid-plane deformation field and discrete surface strain measurements, allowing for the deployment of strain sensors based on single-surface (top/bottom) strain information. Moreover, the algorithm takes into account the effect of transverse shear strain measurements and formulates the calculation process based on elasticity theory and strain-stress constitutive relation. The accuracy and applicability of the proposed method are validated through numerical and experimental tests on various thickness-width ratio plate structures.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Engineering, Multidisciplinary
Kangyu Chen, Kaituo Cao, Guoming Gao, Hong Bao
Summary: An effective computational method utilizing fewer strain sensors to reconstruct the Timoshenko beam under complex loads is proposed, combining iFEM as the basic framework and IGA as an improved strategy. The method simplifies kinematic equations, establishes relationships between rotation deformation and surface measured strains, and determines geometric variables through constitutive equations and boundary conditions. Experimental results demonstrate higher accuracy than iFEM under complex loads.
Article
Engineering, Mechanical
Tao Jiang, Jingwen Zhu, Yanpei Gao, Liang Ren, Chunxu Qu, Dongsheng Li
Summary: Shape sensing is crucial for ensuring structural safety, and the existing methods are limited in sensing large deformations. This paper proposes a new method called analogy stiffness upgrading (ASU) to predict nonlinear deformations of beam structures. The ASU method uses the inverse finite element method (iFEM) to predict initial displacement field and compute analogy stiffness matrix, which is then upgraded using coordinate transformation. Numerical examples and model tests demonstrate the superior precision of the ASU method in predicting largely deformed shapes.
JOURNAL OF ENGINEERING MECHANICS
(2023)
Article
Mechanics
Feifei Zhao, Ruijie Du, Junli Wang, Feng Zhang, Bao Hong
Summary: The inverse finite element method (iFEM) has been used for shape sensing of small displacements based on linear elastic theory. However, it is not suitable for anisotropic composite structures with large deformation. Therefore, a nonlinear iFEM algorithm is proposed to monitor the linear and nonlinear deformation of anisotropic composite beams. The proposed approach can improve the reconstruction accuracy by 4% compared to the linear iFEM method.
COMPOSITE STRUCTURES
(2023)
Article
Mathematics, Applied
Olha Ivanyshyn Yaman, Frederique Le Louer
Summary: The study analyzes an inverse boundary value problem in two-dimensional viscoelastic media with a generalized impedance boundary condition on the inclusion. The uniqueness of identifying impedance parameters from measured data produced by incident plane waves has been established. The theoretical results are illustrated through numerical experiments generated by an inverse algorithm recovering impedance parameters and the density solution simultaneously.
SIAM JOURNAL ON APPLIED MATHEMATICS
(2021)
Article
Chemistry, Analytical
Dario Poloni, Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is widely used in the field of Structural Health Monitoring (SHM). It can reconstruct the displacement field of a beam or shell structure independently of external loading conditions and material properties based on sparse strain measurements. However, the iFEM requires triaxial strain measurements, which are expensive and impractical in real-world applications. To address this issue, pre-extrapolation techniques have been developed to reduce the number of required sensors. However, for structures with regions of different thicknesses, separate extrapolation is needed due to thickness-induced discontinuities in the strain field. This paper proposes a novel method that extrapolates the measured strain field in a thickness-normalized space, effectively reducing the costs of iFEM-based SHM systems.
Article
Mechanics
Makito Kobayashi, Hideharu Ogino, Magnus Burman, Daichi Wada, Hirotaka Igawa, Hideaki Murayama
Summary: In this study, the overall displacement of a sandwich panel with CFRP faces and an aluminum honeycomb core was reconstructed using the inverse finite element method (iFEM). The strain distributions were measured by fiber-optic sensors and an interpolation method was proposed to calculate the overall strain fields. The proposed method successfully and accurately measured the strain distributions and reconstructed the overall strain fields and displacement of the sandwich panel.
COMPOSITE STRUCTURES
(2023)
Article
Thermodynamics
Feiding Zhu, Jincheng Chen, Yuge Han, Dengfeng Ren
Summary: This study proposed a simple method based on deep learning to estimate thermal boundary condition parameters in the transient inverse heat transfer problem. By combining convolutional neural network (CNN) and long short-term memory networks (LSTM), real-time prediction of multiple time-varying parameters can be achieved. Experimental results showed that the proposed model outperformed standalone models in estimating multiple time-varying parameters.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mathematics, Applied
Chifaa Ghanmi, Saloua Mani Aouadi, Faouzi Triki
Summary: This study examines a one-dimensional inverse Stefan problem for the heat equation, showing through a logarithmic stability estimate that the inversion may be severely ill-posed. A direct algorithm with a regularization term is proposed to solve the nonlinear inverse problem. Numerical tests using noisy data are conducted, providing relative errors.
APPLICABLE ANALYSIS
(2022)
Article
Engineering, Multidisciplinary
Shengtao Niu, Yong Zhao, Hong Bao
Summary: This study proposes an enhanced inverse finite element method (iFEM) to reconstruct the structural displacements based on strain data collected from a single surface. The method eliminates the limitations of traditional methods and reduces the number of sensors required. The accuracy and applicability of the method are validated through numerical and experimental analyses.
Article
Mathematics, Applied
Zhiyuan Geng, Fanghua Lin
Summary: This paper studies the shape optimization problem of liquid crystal droplets and establishes the existence of an optimal shape with two cusps on the boundary. It also investigates the properties of the droplet's boundary and the asymptotic behavior of the optimal shape as the volume approaches extremes.
ARCHIVE FOR RATIONAL MECHANICS AND ANALYSIS
(2022)
Article
Engineering, Multidisciplinary
Tianzhi Li, Francesco Cadini, Manuel Chiachio, Juan Chiachio, Claudio Sbarufatti
Summary: This paper presents a novel particle filter-based framework for predicting the shape of delamination. The delamination image is discretized into a mesh, and a data-driven function is used to fit the position of each node, allowing for the prediction of delamination shape progression.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
A. Esmaeili, C. Sbarufatti, K. Youssef, A. Jimenez-Suarez, A. Urena, A. M. S. Hamouda
Summary: This study investigated the effect of toroidal stirring-assisted sonication on CNT doped epoxy nanocomposites, showing that M2 batch exhibited better mechanical, electrical, and piezoresistivity performance compared to M1 batch. Tensile and fracture tests were conducted, revealing a 70% increase in tensile strength and a 17% increase in fracture toughness for M2 batch. Additionally, the piezoresistive-sensitivity of M2 batch increased by 14% compared to M1 batch. Different trends in piezoresistivity were observed in the fracture test before macroscopic damage, attributed to the state of CNT dispersion.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2022)
Article
Engineering, Mechanical
Luca Colombo, M. D. Todd, C. Sbarufatti, M. Giglio
Summary: This study proposes a unique and coherent framework for optimal detector and sensing network design for SHM. Multi-objective optimization is used to optimize sensor placement, maximizing classification performance and minimizing total cost simultaneously. Numerical verification and result validation demonstrate the advantages of the optimization scheme in terms of cost savings and improvement in detection performance.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Mechanical
Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is a model-based technique that uses an optimized strain sensor network to compute the displacement field of a structure. By using strain pre-extrapolation techniques, the strain values in areas without physical sensors can be predicted, with support from the physical knowledge of the discontinuity and its analytical stress formulation, improving the field reconstruction of iFEM.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Aerospace
Xuan Zhou, Daniele Oboe, Dario Poloni, Claudio Sbarufatti, Leiting Dong, Marco Giglio
Summary: In the field of adhesive bonding in aeronautic structures, debonding under fatigue loading is a common failure mode. Researchers have developed a joint distribution adaptation method for regression to address multi-output problems, demonstrating significant improvements in damage quantification accuracy. The proposed approach could potentially be integrated into fleet-level digital twins for heterogeneous systems with nominally identical components.
Article
Chemistry, Analytical
Dario Poloni, Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is widely used in the field of Structural Health Monitoring (SHM). It can reconstruct the displacement field of a beam or shell structure independently of external loading conditions and material properties based on sparse strain measurements. However, the iFEM requires triaxial strain measurements, which are expensive and impractical in real-world applications. To address this issue, pre-extrapolation techniques have been developed to reduce the number of required sensors. However, for structures with regions of different thicknesses, separate extrapolation is needed due to thickness-induced discontinuities in the strain field. This paper proposes a novel method that extrapolates the measured strain field in a thickness-normalized space, effectively reducing the costs of iFEM-based SHM systems.
Article
Chemistry, Physical
Mohammad Rezasefat, Alessio Beligni, Claudio Sbarufatti, Sandro Campos Amico, Andrea Manes
Summary: This study investigates the impact of pre-existing damage on the low-velocity impact response of CFRP through experiments and numerical simulations. A material model based on continuum damage mechanics is developed in Abaqus/Explicit. The model is validated through finite element simulations at the single-element level and more complex models are used to simulate different specimens subjected to low-velocity impacts. The presence of pre-existing damage near the impact region results in severe changes in mechanical response, while impacts farther away from the region show similar results as those on pristine specimens.
Article
Engineering, Aerospace
Xuan Zhou, Claudio Sbarufatti, Marco Giglio, Leiting Dong, Satya N. Atluri
Article
Engineering, Mechanical
Dario Poloni, Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is used to reconstruct the full-field displacement on beam or shell structures using a network of strain sensors. A Gaussian Process is proposed as a strain pre-extrapolation and interpolation technique to provide strain values and compute the uncertainty on the reconstructed displacement field.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Mechanical
Xuan Zhou, Claudio Sbarufatti, Marco Giglio, Leiting Dong
Summary: Online damage quantification suffers from insufficient labeled data, but adopting domain adaptation can improve its accuracy. However, existing domain adaptation methods are not suitable for damage quantification as it is a regression problem with continuous labels. This study proposes a novel domain adaptation method, the Online Fuzzy-set-based Joint Distribution Adaptation for Regression, which converts real-valued labels into fuzzy class labels and measures distribution discrepancy to achieve accurate damage quantification. The proposed method is demonstrated to significantly improve damage quantification in a realistic environment, and it is expected to be applied to fleet-level digital twin considering individual differences.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Chemistry, Analytical
Daniele Oboe, Dario Poloni, Claudio Sbarufatti, Marco Giglio
Summary: The inverse finite element method (iFEM) is used to compute the displacement and strain field of a structure based on strain measurements and a geometric discretization. Previous works focused on damage detection and localization, but did not estimate the damage size accurately. To address this issue, a new approach is proposed, introducing damage systematically in the iFEM model to minimize discrepancy with the physical structure. The approach was experimentally verified on an aluminum plate subjected to fatigue crack propagation.
Article
Instruments & Instrumentation
Dario Poloni, Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: In the past two decades, the aerospace industry has shifted to using composite materials like carbon fiber reinforced polymers (CFRP) instead of aluminum for lighter and fuel-efficient aircrafts. This shift has resulted in the use of adhesive bonding for structural connections and repairs. However, detecting and predicting the debonding of these adhesive interfaces is challenging, leading to increased maintenance costs and reduced platform availability. This paper proposes an inverse finite element method (iFEM) as a load and material independent approach to estimate debonding entity in adhesive-bonded joints, which can be considered a significant scientific advancement in this field.
SMART MATERIALS AND STRUCTURES
(2023)
Proceedings Paper
Engineering, Civil
Dario Poloni, Daniele Oboe, Claudio Sbarufatti, Marco Giglio
Summary: This paper proposes a pre-extrapolation technique based on Gaussian Process for the strain field in the Inverse Finite Element method (iFEM), aiming to improve the solution when the sensor network is sparse and measureless elements are present. The proposed technique incorporates measurement uncertainty and provides confidence intervals for the solution.
EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 2
(2023)
Proceedings Paper
Engineering, Civil
Daniele Oboe, Dario Poloni, Claudio Sbarufatti, Marco Giglio
Summary: The inverse Finite Element Method (iFEM) is a model-based technique that calculates the displacement field of a structure using strain measurements and geometric discretization. It has various applications in Structural Health Monitoring (SHM), mainly focused on damage detection and localization. This study proposes a novel iFEM approach to estimate damage size without the need for a database of damage models. The technique systematically increases the damage size until the strain discrepancy between experimental measurements and numerical strain reconstruction is minimized.
EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 1
(2023)
Article
Engineering, Mechanical
Xuanen Kan, Yanjun Lu, Fan Zhang, Weipeng Hu
Summary: A blade disk system is crucial for the energy conversion efficiency of turbomachinery, but differences between blades can result in localized vibration. This study develops an approximate symplectic method to simulate vibration localization in a mistuned bladed disk system and reveals the influences of initial positive pressure, contact angle, and surface roughness on the strength of vibration localization.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Zimeng Liu, Cheng Chang, Haodong Hu, Hui Ma, Kaigang Yuan, Xin Li, Xiaojian Zhao, Zhike Peng
Summary: Considering the calculation efficiency and accuracy of meshing characteristics of gear pair with tooth root crack fault, a parametric model of cracked spur gear is established by simplifying the crack propagation path. The LTCA method is used to calculate the time-varying meshing stiffness and transmission error, and the results are verified by finite element method. The study also proposes a crack area share index to measure the degree of crack fault and determines the application range of simplified crack propagation path.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Rongjian Sun, Conggan Ma, Nic Zhang, Chuyo Kaku, Yu Zhang, Qirui Hou
Summary: This paper proposes a novel forward calculation method (FCM) for calculating anisotropic material parameters (AMPs) of the motor stator assembly, considering structural discontinuities and composite material properties. The method is based on multi-scale theory and decouples the multi-scale equations to describe the equivalence and equivalence preconditions of AMPs of two scale models. The effectiveness of this method is verified by modal experiments.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Hao Zhang, Jiangcen Ke
Summary: This research introduces an intelligent scheduling system framework to optimize the ship lock schedule of the Three Gorges Hub. By analyzing navigational rules, operational characteristics, and existing problems, a mixed-integer nonlinear programming model is formulated with multiple objectives and constraints, and a hybrid intelligent algorithm is constructed for optimization.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Jingjing He, Xizhong Wu, Xuefei Guan
Summary: A sensitivity and reliability enhanced ultrasonic method has been developed in this study to monitor and predict stress loss in pre-stressed multi-layer structures. The method leverages the potential breathing effect of porous cushion materials in the structures to increase the sensitivity of the signal feature to stress loss. Experimental investigations show that the proposed method offers improved accuracy, reliability, and sensitivity to stress change.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Benyamin Hosseiny, Jalal Amini, Hossein Aghababaei
Summary: This paper presents a method for monitoring sub-second or sub-minute displacements using GBSAR signals, which employs spectral estimation to achieve multi-dimensional target detection. It improves the processing of MIMO radar data and enables high-resolution fast displacement monitoring from GBSAR signals.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xianze Li, Hao Su, Ling Xiang, Qingtao Yao, Aijun Hu
Summary: This paper proposes a novel method for bearing fault identification, which can accurately identify faults with few samples under complex working conditions. The method is based on a Transformer meta-learning model, and the final result is determined by the weighted voting of multiple models.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xiaomeng Li, Yi Wang, Guangyao Zhang, Baoping Tang, Yi Qin
Summary: Inspired by chaos fractal theory and slowly varying damage dynamics theory, this paper proposes a new health monitoring indicator for vibration signals of rotating machinery, which can effectively monitor the mechanical condition under both cyclo-stationary and variable operating conditions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Hao Wang, Songye Zhu
Summary: This paper extends the latching mechanism to vibration control to improve energy dissipation efficiency. An innovative semi-active latched mass damper (LMD) is proposed, and different latching control strategies are tested and evaluated. The latching control can optimize the phase lag between control force and structural response, and provide an innovative solution to improve damper effectiveness and develop adaptive semi-active dampers.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Menghao Ping, Xinyu Jia, Costas Papadimitriou, Xu Han, Chao Jiang, Wang-Ji Yan
Summary: Identification of non-Gaussian processes is a challenging task in engineering problems. This article presents an improved orthogonal series expansion method to convert the identification of non-Gaussian processes into a finite number of non-Gaussian coefficients. The uncertainty of these coefficients is quantified using polynomial chaos expansion. The proposed method is applicable to both stationary and nonstationary non-Gaussian processes and has been validated through simulated data and real-world applications.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Lei Li, Wei Yang, Dongfa Li, Jianxin Han, Wenming Zhang
Summary: The frequency locking phenomenon induced by modal coupling can effectively overcome the dependence of peak frequency on driving strength in nonlinear resonant systems and improve the stability of peak frequency. This study proposes the double frequencies locking phenomenon in a three degrees of freedom (3-DOF) magnetic coupled resonant system driven by piezoelectricity. Experimental and theoretical investigations confirm the occurrence of first frequency locking and the subsequent switching to second frequency locking with the increase of driving force. Furthermore, a mass sensing scheme for double analytes is proposed based on the double frequencies locking phenomenon.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Kai Ma, Jingtao Du, Yang Liu, Ximing Chen
Summary: This study explores the feasibility of using nonlinear energy sinks (NES) as replacements for traditional linear tuned mass dampers (TMD) in practical engineering applications, specifically in diesel engine crankshafts. The results show that NES provides better vibration attenuation for the crankshaft compared to TMD under different operating conditions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Wentao Xu, Li Cheng, Shuaihao Lei, Lei Yu, Weixuan Jiao
Summary: In this study, a high-precision hydraulic mechanical stand and a vertical mixed-flow pumping station device were used to conduct research on cavitation signals of mixed-flow pumps. By analyzing the water pressure pulsation signal, it was found that the power spectrum density method is more sensitive and capable of extracting characteristics compared to traditional time-frequency domain analysis. This has significant implications for the identification and prevention of cavitation in mixed-flow pump machinery.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xiaodong Chen, Kang Tai, Huifeng Tan, Zhimin Xie
Summary: This paper addresses the issue of parasitic motion in microgripper jaws and its impact on clamping accuracy, and proposes a symmetrically stressed parallelogram mechanism as a solution. Through mechanical modeling and experimental validation, the effectiveness of this method is demonstrated.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Zhifeng Shi, Gang Zhang, Jing Liu, Xinbin Li, Yajun Xu, Changfeng Yan
Summary: This study provides useful guidance for early bearing fault detection and diagnosis by investigating the effects of crack inclination and propagation direction on the vibration characteristics of bearings.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
