Liu, D, Yang, L, He, X, Wang, R & Luo, Q 2018, 'Atomistic-scale simulations of mechanical behavior of suspended single-walled carbon nanotube bundles under nanoprojectile impact', COMPUTATIONAL MATERIALS SCIENCE, vol. 142, pp. 237-243.View/Download from: UTS OPUS or Publisher's site
Luo, Q & Tong, L 2017, 'A deformation mechanism based material model for topology optimization of laminated composite plates and shells', COMPOSITE STRUCTURES, vol. 159, pp. 246-256.View/Download from: Publisher's site
Luo, Q & Tong, L 2016, 'An algorithm for eradicating the effects of void elements on structural topology optimization for nonlinear compliance', STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, vol. 53, no. 4, pp. 695-714.View/Download from: Publisher's site
Luo, Q & Tong, L 2016, 'Elimination of the Effects of Low Density Elements in Topology Optimization of Buckling Structures', INTERNATIONAL JOURNAL OF COMPUTATIONAL METHODS, vol. 13, no. 6.View/Download from: Publisher's site
Luo, Q & Tong, L 2016, 'Solutions for Clamped Adhesively Bonded Single Lap Joint With Movement of Support End and Its Application to a Carbon Nanotube Junction in Tension', JOURNAL OF ADHESION, vol. 92, no. 5, pp. 349-379.View/Download from: Publisher's site
Sui, C, Luo, Q, He, X, Tong, L, Zhang, K, Zhang, Y, Zhang, Y, Wu, J & Wang, C 2016, 'A study of mechanical peeling behavior in a junction assembled by two individual carbon nanotubes', CARBON, vol. 107, pp. 651-657.View/Download from: Publisher's site
Tong, LY & Luo, QT 2016, 'Design of cellular structures with multi-volume fractions using topology optimization', Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics, vol. 33, no. 4, pp. 516-521.View/Download from: Publisher's site
© 2016, Editorial Office of Chinese Journal of Computational Mechanics. All right reserved. This study presents a method for finding optimum topology of cellular structure made from one material using an appropriate addition manufacturing process and tailored with different volume fractions in different structural domains. The topology optimization problem is firstly formulated allowing multi-volume fractions in cellular structures. An algorithm based on MIS T with multi-thresholds is presented and interfaced with commercial finite element analysis software. Numerical examples for the minimum mean compliance problem with three volume fractions are presented to illustrate the present algorithm. The present numerical results show that, for the optimum topology design with three volume fractions, there exists an optimum combination that yields an additional 10% reduction in the minimum mean compliance when compared to the design with two volume fractions.
Luo, Q & Tong, L 2015, 'Optimal Designs for Vibrating Structures Using a Moving Isosurface Threshold Method With Experimental Study', JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME, vol. 137, no. 6.View/Download from: Publisher's site
Luo, Q & Tong, L 2015, 'Structural topology optimization for maximum linear buckling loads by using a moving iso-surface threshold method', STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, vol. 52, no. 1, pp. 71-90.View/Download from: Publisher's site
Wang, C, He, X, Tong, L, Luo, Q, Li, Y, Song, Q, Lv, X, Shang, Y, Peng, Q & Li, J 2015, 'Tensile failure mechanisms of individual junctions assembled by two carbon nanotubes', COMPOSITES SCIENCE AND TECHNOLOGY, vol. 110, pp. 159-165.View/Download from: Publisher's site
Zheng, S, Tong, L & Luo, Q 2015, 'Finite element formulations and algorithms for coupled multiphysics analysis of 0-1 and 0-3 polarized PLZT actuators', INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, vol. 49, no. 4, pp. 513-530.View/Download from: Publisher's site
Wang, C, Peng, Q, Wu, J, He, X, Tong, L, Luo, Q, Li, J, Moody, S, Liu, H, Wang, R, Du, S & Li, Y 2014, 'Mechanical characteristics of individual multi-layer graphene-oxide sheets under direct tensile loading', CARBON, vol. 80, pp. 279-289.View/Download from: Publisher's site
Luo, Q & Tong, L 2013, 'Adaptive pressure-controlled cellular structures for shape morphing I: design and analysis', SMART MATERIALS AND STRUCTURES, vol. 22, no. 5.View/Download from: Publisher's site
Luo, Q & Tong, L 2013, 'Adaptive pressure-controlled cellular structures for shape morphing: II. Numerical and experimental validation', SMART MATERIALS AND STRUCTURES, vol. 22, no. 5.View/Download from: Publisher's site
Luo, Q & Tong, L 2012, 'Analytic formulas of energy release rates for delamination using a global-local method', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 49, no. 23-24, pp. 3335-3344.View/Download from: Publisher's site
Luo, Q & Tong, L 2012, 'Multifunctional behaviors of an indium tin oxide/PbLa(ZrTi)O-3/indium tin oxide wafer illuminated by ultraviolet light', JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, vol. 23, no. 7, pp. 765-774.View/Download from: Publisher's site
Luo, Q, Luo, Z & Tong, L 2011, 'A Variational Principle And Finite Element Formulation For Multi-Physics Plzt Ceramics', Mechanics Research Communications, vol. 38, no. 3, pp. 198-202.View/Download from: UTS OPUS or Publisher's site
This research presents an extended variational principle and a finite element formulation for multiphysics analysis of PLZT (lanthanum zirconate titanate) ceramics by including the photovoltaic and optothermic effects. The photo-induced electrical and th
Luo, Z, Luo, Q, Tong, L, Gao, W & Song, C 2011, 'Shape morphing of laminated composite structures with photostrictive actuators via topology optimization', Composite Structures, vol. 93, no. 2, pp. 406-418.View/Download from: UTS OPUS or Publisher's site
In this paper a new design method is presented for achieving remote wireless shape morphing of laminated composite structures using topology optimization methods A recently emerging family of smart materials photostrictive materials is Introduced as the actuation discipline to implement the active control of optical structures by utilizing the photostriction mechanism which arises from the superposition of photovoltaic effect and converse piezoelectric effect when exposed to the illumination of near ultraviolet light In terms of the Mindlin plate theory of first-order shear deformation a finite element formulation including multiphysics effects of photovoltaic pyroelectric and thermal expansion is developed to model composite structures of ferroelectric materials polarized in 0-1 and 0-3 directions respectively The design is formulated as a multi-constrained optimization problem with a least square objective function to minimize structural shape errors The topology optimization method is used as a systematic design approach to seek the optimal topologies of material layouts for both the photostrictive and host layers as well as the actuator light distribution In terms of design sensitivity analysis many gradient-based optimization algorithms can be applied to solve the problem effectively Numerical examples are presented to demonstrate the effectiveness of this method in the field of active photonic control of laminated composite structures
Luo, Q & Tong, L 2011, '3D Model of Coupled Multi-physics Fields for PLZT Ceramics and Its Applications to Photostrictive Plates', JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, vol. 22, no. 1, pp. 17-30.View/Download from: Publisher's site
Luo, Q & Tong, L 2011, 'Ultraviolet-light-induced multi-physics behaviors of 0-3 polarized transparent PLZT plates: I. Experimental testing', SMART MATERIALS AND STRUCTURES, vol. 20, no. 11.View/Download from: Publisher's site
Luo, Q & Tong, L 2011, 'Ultraviolet-light-induced multi-physics behaviors of 0-3 polarized transparent PLZT plates: II. Finite element analysis and validation', SMART MATERIALS & STRUCTURES, vol. 20, no. 11.View/Download from: Publisher's site
Luo, Q & Tong, L 2010, 'Multi-physics field models of photostrictive unimorphs and heterogeneous bimorphs subjected to light illumination and mechanical loading', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 47, no. 16, pp. 2006-2016.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Analytical solutions for nonlinear analysis of composite single-lap adhesive joints', INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES, vol. 29, no. 2, pp. 144-154.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Calculation of Energy Release Rates for Cohesive and Interlaminar Delamination Based on the Classical Beam-adhesive Model', JOURNAL OF COMPOSITE MATERIALS, vol. 43, no. 4, pp. 331-348.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Constitutive equations for 0-3 polarized PLZT actuators', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 46, no. 25-26, pp. 4313-4321.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Constitutive Modeling of Photostrictive Materials and Design Optimization of Microcantilevers', JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, vol. 20, no. 12, pp. 1425-1438.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Energy release rates for interlaminar delamination in laminates considering transverse shear effects', COMPOSITE STRUCTURES, vol. 89, no. 2, pp. 235-244.View/Download from: Publisher's site
Wood, MDK, Tong, L, Luo, Q, Sun, X, Katzos, A & Rispler, AR 2009, 'Failure of Stitched Composite L-Joints Under Tensile Loading - Experiment and Simulation', JOURNAL OF REINFORCED PLASTICS AND COMPOSITES, vol. 28, no. 6, pp. 715-742.View/Download from: Publisher's site
Luo, Q & Tong, L 2008, 'Analytical solutions for adhesive composite joints considering large deflection and transverse shear deformation in adherends', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 45, no. 22-23, pp. 5914-5935.View/Download from: Publisher's site
Luo, Q & Tong, L 2007, 'A segment based sequential least squares algorithm with optimum energy control for tracking the dynamic shapes of smart structures', SMART MATERIALS & STRUCTURES, vol. 16, no. 5, pp. 1517-1526.View/Download from: Publisher's site
Luo, Q & Tong, L 2007, 'Fully-coupled nonlinear analysis of single lap adhesive joints', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 44, no. 7-8, pp. 2349-2370.View/Download from: Publisher's site
Wood, MDK, Sun, X, Tong, L, Luo, Q, Katzos, A & Rispler, A 2007, 'A new ENF test specimen for the mode II delamination toughness testing of stitched woven CFRP laminates', JOURNAL OF COMPOSITE MATERIALS, vol. 41, no. 14, pp. 1743-1772.View/Download from: Publisher's site
Luo, Q & Tong, L 2006, 'A sequential linear least square algorithm for tracking dynamic shapes of smart structures', INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, vol. 67, no. 1, pp. 66-88.View/Download from: Publisher's site
Luo, Q & Tong, L 2006, 'High precision shape control of plates using orthotropic piezoelectric actuators', FINITE ELEMENTS IN ANALYSIS AND DESIGN, vol. 42, no. 11, pp. 1009-1020.View/Download from: Publisher's site
Luo, Q & Tong, L 2004, 'Linear and higher order displacement theories for adhesively bonded lap joints', International Journal of Solids and Structures, vol. 41, no. 22-23, pp. 6351-6381.View/Download from: Publisher's site
This work presents an adhesive model for stress analysis of bonded lap joints, which can be applied to model thin and thick adhesive layers. In this theory, linear variations of displacement components along the adhesive thickness are firstly assumed, and the longitudinal strain and the Poisson's effect of the adhesive are modeled. A differential form of the equilibrium equations for the adherends is analytically solved by means of compatible relations of the adhesive deformation. The derived shear and peel stresses are compared with the classical adhesive model of continuous springs with constant shear and peel stresses, and validated with two-dimensional finite element results of the geometrically nonlinear analysis using a commercial package. The numerical results show that the present linear displacement theory can be applied to both thin and moderately thick adhesive layers. The present formulation of the linear displacement theory is then extended to the higher order displacement theory for stress analysis of a thick adhesive, whose numerical results are also compared with those of the finite element computation. © 2004 Elsevier Ltd. All rights reserved.
Luo, QT & Tong, LY 2004, 'Linear and higher order displacement theories for adhesively bonded lap joints', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 41, no. 22-23, pp. 6351-6381.View/Download from: Publisher's site
Luo, QT & Tong, LY 2003, 'Exact dynamic solutions to piezoelectric smart beams including peel stresses - Part II: Numerical results, comparison and approximate solution', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 40, no. 18, pp. 4813-4836.View/Download from: Publisher's site
Tong, LY & Luo, QT 2003, 'Exact dynamic solutions to piezoelectric smart beams including peel stresses - I: Theory and application', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 40, no. 18, pp. 4789-4812.View/Download from: Publisher's site
Luo, QT & Tong, LY 2002, 'Exact static solutions to piezoelectric smart beams including peel stresses I: Theoretical formulation', INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES, vol. 39, no. 18, pp. 4677-4695.View/Download from: Publisher's site
© Springer International Publishing AG, part of Springer Nature 2018. All rights are reserved. This chapter presents analytical approach for determining stress and strength of adhesively bonded joints. Selected applications of adhesively bonded joints are discussed first, and then mathematical models for stress analysis of these joints are outlined. Various closed-form solutions for adhesive stresses and edge bending moment for balanced single-lap joints are presented and compared. The method for finding analytical solutions for asymmetric and unbalanced adhesive joints is also discussed. Explicit expressions for mode I and mode II energy release rates for cohesive failure and interfacial debonding are presented for asymmetric joints with a semi-infinitive length subjected to general load combinations.
Analytical formulae developed by Luo and Tong (2009) to determine the mixed mode strain energy release rates of laminated and co-cured composite structures and joints are reviewed. The effects of varying loading conditions and geometries on the mode mixity found analytically are investigated via a parametric study. A critical evaluation of the analytical formulae indicates that the formulae are robust in calculating the total strain energy release rate, but may underestimate the mode II component compared with the finite element analysis and experimental results. Possible reasons for this discrepancy are discussed, including the effect of stress concentrations and singularities at the crack tip. © 2011 Woodhead Publishing Limited. All rights reserved.
This chapter presents analytical models for cracked lap shear joints. Two analytical frameworks are introduced: (1) the overlap is treated as an entire beam to find displacements and force components of the cracked lap shear joints firstly, and then the adherends in the overlap region are treated as individual beams to find adhesive stresses and energy release rates; (2) individual beams are considered only; displacements, force components and adhesive stresses are determined simultaneously by solving the coupled differential equations. Geometrically-nonlinear features of cracked lap shear joints are investigated. Strength of materials and fracture mechanics based failure criteria are discussed. © 2008 Springer Berlin Heidelberg.
Luo, Q & Tong, L 2018, 'Optimal design of bi- And multi-stable compliant cellular structures', Proceedings of the ASME Design Engineering Technical Conference, ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, ASME, Quebec City, Quebec, Canada.View/Download from: UTS OPUS or Publisher's site
Copyright © 2018 ASME. This paper presents optimal design for nonlinear compliant cellular structures with bi- and multi-stable states via topology optimization. Based on the principle of virtual work, formulations for displacements and forces are derived and expressed in terms of stress and strain in all load steps in nonlinear finite element analysis. Optimization for compliant structures with bi-stable states is then formulated as: 1) to maximize the displacement under specified force larger than its critical one; and 2) to minimize the reaction force for the prescribed displacement larger than its critical one. Algorithms are developed using the present formulations and the moving iso-surface threshold method. Optimal design for a unit cell with bi-stable states is studied first, and then designs of multistable compliant cellular structures are discussed.
This article investigates topology optimization for normal mode analysis using a moving iso-surface threshold method. Fundamental natural frequency needs to be calculated for many engineering structures and maximizing its value is an interesting topic in topology optimization. Optimal design for the maximum fundamental frequency may appear to be a trivial issue or impractical design. Reinforcements by introducing non-designable elements and non-structural mass or concentrated mass are often used. In this article, these issues will be solved by choosing an appropriate F function that is an integral function in the moving iso-surface threshold method. The proposed F function is expressed as strain and kinetic energy densities for a series of normal modes. By selecting the energy densities of different mode shapes, optimal topologies to maximize structural fundamental frequency are studied. © (2014) Trans Tech Publications, Switzerland.
Luo, Q & Tong, L 2009, 'Fracture Prediction of Adhesively Bonded Structures Using Energy Release Rates', JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, TAYLOR & FRANCIS LTD, pp. 1415-1440.View/Download from: Publisher's site
Luo, Q & Tong, L 2009, 'Use of optically transparent lead lanthanum zirconate titanate as actuators and sensors', SECOND INTERNATIONAL CONFERENCE ON SMART MATERIALS AND NANOTECHNOLOGY IN ENGINEERING, 2nd International Conference on Smart Materials and Nanotechnology in Engineering, SPIE-INT SOC OPTICAL ENGINEERING, Weihai, PEOPLES R CHINA.View/Download from: Publisher's site
Luo, Q & Tong, L 2008, 'Moving least square approximation for tracking dynamic shapes of smart structures', 7th European Conference on Structural Dynamics, EURODYN 2008.
This paper presents a moving least square approximation for tracking dynamic shapes of flexible smart structures. The dynamic structural shape is referred to as the shape of a structure that varies with respect to time, and the tracking technique is to find an optimum stimuli input history for each smart material based actuator over a time period so that the desired structural movements can be achieved with best approximation. In the theoretical formulation, dynamic equations of smart structures are presented by using the finite element method, and then the moving least square approximation is introduced for determining the optimum time dependent stimuli input combining a least square approximation method and a selected numerical integration scheme. The formulation indicates that this algorithm can be used to find the optimum time dependent stimuli input for best matching desired structural movement of a smart structure. The present novel approach is then demonstrated through numerical examples for tracking dynamic shapes of piezoelectric material based smart beams and plates as well as comparison with the experimental results for smart beams with piezoelectric actuators. It is shown that the proposed moving least square approximation approach is capable of efficiently simulating dynamic shape control for smart structures.
Luo, Q & Tong, L 2007, 'Nonlinear analysis of bonded composite patch repairs', ICCM International Conferences on Composite Materials.
This paper presents a geometrical nonlinear analysis for the single strap model of single-sided adhesively bonded composite patch repairs to cracked structures subjected to tension. In this analysis, the equilibrium equations are derived by considering the large deflections of the substrates along their entire lengths. By neglecting the higher order items, analytical solutions for the single-strap patch repair model are obtained, and the solutions are then simplified for engineering applications. The geometrically-nonlinear finite element analysis was conducted using MSC/NASTRAN to validate the present closed-form solutions. The numerical results indicate that the present closed-form solutions and their simplifications correlate very well with the nonlinear finite element computations.