Article
Engineering, Multidisciplinary
Yan Li, Wenhua Wang, Mingpeng Pan, Wenhong Cao, Xiakang Ma, Yuebing Li
Summary: This paper investigates the effect of autofrettage design approach on the fatigue life of seamless steel cylinders. By analyzing the stress distribution and residual stress, the fatigue crack growth rate of the cylinders is determined. The experimental results show that autofrettage design can improve the fatigue life of the cylinders.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2023)
Article
Mathematics, Applied
Santhosh Karnik, Rongrong Wang, Mark Iwen
Summary: The remarkable successes of neural networks in solving a wide range of inverse problems have raised questions about the theory behind their effectiveness. This study presents a general method for bounding the complexity required for neural networks to approximate continuous functions on high-dimensional sets, aiming to bridge the gap between theory and practice.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2024)
Article
Geochemistry & Geophysics
Amartansh Dubey, Ross Murch
Summary: In this work, a novel linear iterative solution, called DxPRIM, is presented for an electromagnetic inverse scattering problem without phase data (PD-ISP). This method extends the validity range of the conventional Rytov approximation and accurately reconstructs the real and imaginary components of permittivity for strongly scattering, lossy media. Simulation and experimental examples demonstrate that DxPRIM outperforms state-of-the-art phaseless techniques in reconstructing scatterers with phaseless measurement data.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Engineering, Electrical & Electronic
Tiantian Yin, Li Pan, Xudong Chen
Summary: This article proposes an iterative method called the subspace-based distorted-Rytov iterative method (S-DRIM) for solving inverse scattering problems. The method utilizes the subspace-Rytov approximation (SRA) and updates the parameters of the background medium in each iteration of S-DRIM. Through simulations, the approximation errors of both the Rytov Approximation (RA) and SRA are analyzed and compared in various background media. The performance of S-DRIM is verified using both synthetic and experimental data, showing that it outperforms the non-iterative SRA inversion method for mild scatterer reconstructions and has a smaller reconstruction error in optimization processes compared to the distorted-Rytov iterative method (DRIM).
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Mechanical
Carl Faellgren, Michael Vormwald, Heinz Thomas Beier, Andreas Kleemann, Susanne Kleemann
Summary: This research evaluates the potential of using ultra-high-strength steel in cyclically loaded, inner-pressure bearing components. Through experimental and numerical analysis, the effects of autofrettage on material behavior are determined, providing valuable insights for such applications.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Mechanics
Avinash Chetry, S. M. Kamal, V. K. Mehta
Summary: In this work, numerical analysis is conducted to evaluate the effectiveness of rotational autofrettage for strengthening hollow circular disks. The results indicate that this method can significantly enhance the load carrying capacity of the disks.
INTERNATIONAL JOURNAL OF APPLIED MECHANICS
(2023)
Article
Engineering, Electrical & Electronic
Tao Shan, Zhichao Lin, Xiaoqian Song, Maokun Li, Fan Yang, Shenheng Xu
Summary: In this paper, a new physics-constrained approach is proposed to solve 2-D inverse scattering problems (ISPs) by extending physics-informed supervised residual learning (PhiSRL) with Born approximation (BA). PhiSRL aims to solve ISPs iteratively by applying the convolutional neural networks (CNNs) to learn the update rules of reconstructions. PhiSRL is employed to invert lossy scatterers by introducing BA to linearize ISPs and reduce the computational burden of forward modeling. Numerical and experimental results validate the effectiveness of the proposed approach.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Tiantian Yin, Li Pan, Xudong Chen
Summary: In this article, a novel non-iterative method, called the subspace-Rytov approximation (SRA) method, is proposed to solve inverse scattering problems. This method improves the inversion results by retaining the neglected integral term in the Rytov approximation. The SRA method calculates the major part of the integrand using the subspace method and approximates the integration on the whole space by truncation. Experimental results show that the SRA method outperforms other commonly used methods.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Mathematics, Applied
Junxiong Jia, Qian Zhao, Zongben Xu, Deyu Meng, Yee Leung
Summary: This paper explores extending the traditional finite-dimensional variational Bayes method to infinite-dimensional space for solving inverse problems of partial differential equations. By establishing a general infinite-dimensional mean-field approximate theory, the method is applied to linear inverse problems under Gaussian and Laplace noise assumptions, with numerical experiments confirming its effectiveness.
SIAM JOURNAL ON SCIENTIFIC COMPUTING
(2021)
Article
Construction & Building Technology
Mingqiang Xu, Jian Guo, Shuqing Wang, Jun Li, Hong Hao
Summary: This paper presents a novel approach for structural damage identification using a limited number of modal measurements and ultra-sparse Bayesian regression. The method establishes a linear regression model, iteratively solves insufficient mode orders, and introduces Horseshoe (HS) for ultra-sparse regularization. The approach effectively solves incomplete measurements and provides good stability, making it suitable for structural damage identification with sparse solutions.
STRUCTURAL CONTROL & HEALTH MONITORING
(2021)
Article
Engineering, Multidisciplinary
Naveed Hussain, Faisal Qayyum, Riffat Asim Pasha, Masood Shah
Summary: This research conducted a detailed multi-physics study on a solid fractured gun barrel by numerically simulating 20 thermo-mechanical cycles. Material data from high-temperature compression tests was used in the simulation model. The study compared non-autofrettaged and autofrettaged simulation models to analyze the evolution of strains and stresses in the barrel under combined thermo-mechanical loading cycles.
DEFENCE TECHNOLOGY
(2021)
Article
Mathematics, Applied
Moncef Mahjoub, Ridha Mdimagh
Summary: In this paper, we combine two methods to solve the inverse problem of locating dipolar sources in a restricted domain using measurements of the Cauchy data on a part of the boundary for the Laplace equation. We first extend the boundary measurements by solving an extremal bounded problem in an annulus. Then, we solve the inverse problem of source identification using the reciprocity gap concept applied to the completed data. Numerical tests are conducted to evaluate the effectiveness of source detection with regard to the expansion of the data.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Materials Science, Characterization & Testing
Diego L. Britez, Michael B. Prime, Sana Werda, Raynald Laheurte, Philippe Darnis, Olivier Cahuc
Summary: This paper examines destructive methods for measuring residual stresses, such as the slitting method, and the use of inverse analysis to solve the problem. It shows that the accuracy of the result and the uncertainty component depend on the basis functions used in the inverse solution. The paper introduces a new estimation of the model uncertainty and an improved methodology for selecting the final basis functions, resulting in reduced error and improved uncertainty estimation.
Article
Engineering, Multidisciplinary
Elie A. Badr, Joanne Ishak
Summary: Test results indicated that the modified Goodman equation is favorable in accounting for the effect of both tensile and compressive mean stresses on fatigue life (up to a compressive mean stress to ultimate stress ratio of -0.2). The behavior under compressive mean stress to ultimate stress ratio of less than -0.2 indicated that a linear correction relationship was required.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2021)
Article
Mathematics
Judy P. Yang, Hsiang-Ming Li
Summary: The weighted gradient reproducing kernel collocation method is proposed to recover the heat source described by Poisson's equation. Due to the non-uniqueness of the inverse heat source problem, a weak solution based on a priori assumptions is considered. By introducing a high-order gradient reproducing kernel approximation, the fourth-order partial differential equation (PDE) in the mathematical model can be efficiently solved without calculating the high-order derivatives of reproducing kernel shape functions. The effectiveness of the method is demonstrated through benchmark analysis and four examples.
Article
Mechanics
Saeed H. Moghtaderi, S. Ali Faghidian, Mohsen Asghari
Summary: This study examines the nonlinear vibration characteristics of elastic nano-bars with large vibration amplitudes and proposes an effective analytical method. By applying the nonlocal elasticity theory and strain gradient elasticity theory, the method considers the nano-scale effects and non-classical boundary conditions. This analytical approach can be used for optimized design of vibration-based nano-devices and addressing nonlinear dynamic phenomena.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2023)
Article
Engineering, Multidisciplinary
S. Ali Faghidian, Krzysztof Kamil Zur, Ernian Pan, Jinseok Kim
Summary: The paper presents the mixture stress gradient theory of elasticity, which unifies classical elasticity theory and stress gradient theory, rigorously formulates the boundary-value problem of functionally graded nano-bars, and determines the constitutive law of the axial force field with proper non-standard boundary conditions. By using numerical and analytical methods, the effectiveness of the established theory in characterizing the size-dependent response of functionally graded structural elements is demonstrated.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
S. Ali Faghidian, Krzysztof Kamil Zur, J. N. Reddy
Summary: The proposed higher-order unified gradient elasticity theory effectively characterizes the nanoscopic response of advanced nano-materials, as demonstrated by its application to study the torsional behavior of elastic nano-bars and determine the shear modulus of nano-sized bars in closed-form analytical formula. Additionally, a practical approach to calibrate characteristic lengths is introduced.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Engineering, Multidisciplinary
Hossein Jafarzadeh, Gholam Hossein Farrahi, Valery I. Levitas, Mahdi Javanbakht
Summary: Phase field theory for fracture is developed at large strains with a correct introduction of surface stresses at nanoscale. The expression for surface stresses is consistent with the sharp surface approach and is a result of geometric nonlinearities. The study provides important connections between material parameters and presents a complete system of equations in both deformed and undeformed configurations.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
S. Ali Faghidian, Krzysztof Kamil Zur, Timon Rabczuk
Summary: The mixture unified gradient theory of elasticity is utilized to assess the size-dependent behavior of materials with nano-structural features. Integrating the strain gradient theory and the stress gradient theory with the classical continuum theory, the study examines the dynamics and elastostatic response of nanobars. The established generalized continuum theory proves effective in accurately describing the size-effects at the ultra-small scale, as evidenced by electrostatic and elastodynamic analysis of nanobars.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Editorial Material
Engineering, Multidisciplinary
Krzysztof Kamil Zur, S. Ali Faghidian, J. N. Reddy, K. M. Liew, A. J. M. Ferreira
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Mathematics, Applied
S. Ali Faghidian, Krzysztof Kamil Zur, Isaac Elishakoff
Summary: This study utilizes the mixture unified gradient theory of elasticity to investigate the nanoscopic nonlinear flexure mechanics of nanobeams. Through a mixed variational framework and numerical approach, the size-effect phenomenon associated with stress gradient, strain gradient, and classical elasticity theories is realized and the nonlinear flexural characteristics of nano-sized beams are detected and compared.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Engineering, Multidisciplinary
S. Ali Faghidian, Krzysztof Kamil Zur, Ernian Pan
Summary: The mixture unified gradient theory of elasticity integrates the stress gradient, strain gradient, and classical elasticity theory within a consistent variational framework. It incorporates all the governing equations into a single functional, making it a suitable counterpart for the two-phase local/nonlocal gradient theory. The theory can effectively examine various multi-dimensional structural problems in Engineering Science and has significant practical importance.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Mechanics
S. Ali Faghidian, Isaac Elishakoff
Summary: This paper highlights the importance of the shear coefficient in the Timoshenko-Ehrenfest beam theory and addresses the challenge of determining the appropriate formula for solid rectangular cross-sections. A variational framework is proposed to establish a consistent shear coefficient for prismatic beams, and the efficacy of the introduced coefficient is demonstrated through the discussion of intrinsic anomalies.
Article
Engineering, Mechanical
Seyed Ali Faghidian, Abdelouahed Tounsi
Summary: The dynamic characteristics of elastic nanobeams are rigorously analyzed using the mixture unified gradient theory of elasticity, with closed-form solutions and numerical evaluations. The study shows that the established elasticity model effectively describes the softening and stiffening responses of nanobeams, providing a practical approach to tackle dynamics of nano-structures.
FACTA UNIVERSITATIS-SERIES MECHANICAL ENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
Prudhvi Peri, Kai Fu, Houqiang Fu, Jingan Zhou, Yuji Zhao, David J. Smith
Summary: The morphology of GaN substrates grown by HVPE and by ammonothermal methods was observed to have an impact on the performance of GaN-on-GaN p-i-n diodes. HVPE-grown substrates showed ordered surface features, while ammonothermal substrates did not. Diodes fabricated on HVPE substrates had higher reverse-bias voltages compared to those on ammonothermal substrates.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Coatings & Films
Daniel C. Messina, Kevin A. Hatch, Saurabh Vishwakarma, David J. Smith, Yuji Zhao, Robert J. Nemanich
Summary: Two atomic layer etching methods were investigated for crystalline GaN, involving oxidation, fluorination, and ligand exchange. The etching process was monitored in situ using multiwavelength ellipsometry and characterized through X-ray photoelectron spectroscopy. The results revealed the presence of fluorine and oxygen impurities on the etched surfaces, a slight reduction in thickness, and a lower removal rate than predicted. The observed reduced etch rates were attributed to the ordered structure of the oxide formed on the crystalline GaN surfaces.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Nanoscience & Nanotechnology
Abhinandan Gangopadhyay, Chaomin Zhang, Aymeric Maros, Nikolai Faleev, Richard R. King, Christiana B. Honsberg, David J. Smith
Summary: The atomic-scale structure of extended defects in GaAs/GaAs1-xSbx/GaAs (001) heterostructures has been investigated using aberration-corrected scanning transmission electron microscopy. Two types of defects were identified: a dissociated screw dislocation or a partial dislocation dipole at the tensile-strained GaAs(cap)/GaAs0.34Sb0.66 interface, and a dissociated 90 degrees dislocation at the compressively-strained GaAs0.91Sb0.09/GaAs(substrate) interface. The intrinsic stacking faults associated with these defects were bounded by Shockley partial dislocations.
SCRIPTA MATERIALIA
(2023)
Article
Engineering, Multidisciplinary
S. Ali Faghidian, Isaac Elishakoff
Summary: This study investigates the random vibration of elastic beams at the ultra-small scale using the mixture unified gradient theory of elasticity. The closed-form solution of the space-time correlation function and the mean-square of the transverse displacements of the elastic nanobeam with simply supported ends is obtained. The spatial variation of the mean-square value of the transverse displacements is graphically illustrated and discussed in terms of gradient length-scale parameters.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Engineering, Electrical & Electronic
Kabir Sadeghi, Amir Shamsi, S. Ali Faghidian
Summary: Carbon nanotubes are influential in advanced engineering systems, but classical continuum mechanics is inadequate for accurately describing their structural response. The mixture unified gradient theory of elasticity is applied to study the structural characteristics of nanobars in a nanoscopic scale. This study provides a new benchmark for the analysis and design of pioneering nanosystems.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2023)
Article
Engineering, Multidisciplinary
Abraham Mensah, Srinivas Sriramula
Summary: This paper proposes a pathway for developing efficient performance functions to evaluate the probability of failure for interacting pipeline corrosion clustering defects using a probabilistic finite element-based reliability method. The framework reduces computational cost and offers informed decision-making on risk and maintenance management.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2024)
Article
Engineering, Multidisciplinary
Baozhu Zhang, Wenchun Jiang, Yun Luo, Wei Peng, Yingjie Qiao
Summary: This paper studies the distribution of residual stress in thick wall girth welds using narrow-gap welding. The study finds that the heat input, wall thickness, radius thickness ratio, and number of welding passes have an effect on residual stress. A model for the distribution of welding residual stress through the wall thickness is proposed, and its results are in good agreement with finite element calculation results.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2024)
Article
Engineering, Multidisciplinary
Stefan Culafic, Darko Bajic, Tasko Maneski
Summary: This paper presents experimental research on a branch model conducted in laboratory conditions. The study verifies the linear relationship between stress and internal pressure in the field of elasticity and reveals the occurrences when stresses exceed the yield strength of the branch material, such as plastic deformations of the branch model. The research also defines the dependence of stress on internal pressure in both the field of elasticity and the zone of residual stresses.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2024)
Article
Engineering, Multidisciplinary
Wenchun Jiang, Wenlu Xie, Xinyue Qi, Yangguang Deng, Yu Wan, Xuefang Xie
Summary: Various types of solid-state phase transformations (SSPT) occur during the SA508 steel welding process, leading to complex microstructure distribution and significant influence on residual stress distribution. To better control microstructure and residual stress, optimization of process parameters related to welding thermal cycles is necessary.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2024)
