Guangyong Sun

Hunan University · Department of Vehicle Engineering

Fatal and serious injuries of vulnerable road users (VRU) occur frequently in the events of vehicle impact. Front-end crashworthiness of vehicle can considerably affect VRU injuries in impact accidents, and vehicular design signifies a key issue in automobile engineering. This paper provides a comprehensive review on the state-of-the-art on the ass...

Additively manufactured lattice structures (AMLS) exhibit substantially more freedom in design compared with traditional cellular materials such as honeycombs and stochastic foams. Prior to extensive applications, multiaxial mechanical behaviors of AMLS need to be thoroughly understood. In this study, open-cell Kelvin lattice structures (named as K...

This study proposes a novel topology optimization approach for design of continuous steering fiber path for composite structures using a level set method. The radial basis function (RBF) is employed to construct the level set function (LSF). Fiber orientations are parameterized by LSF and fiber paths can be determined instinctively for the inherent...

This study aims to experimentally explore the influences of stamping conditions on the variations in fiber yarn angle and material properties of continuous fiber reinforced thermoplastics (CoFRTP). First, the upright-orthogonal (O-), biased-orthogonal (B-) and non-orthogonal (N-) specimens were manufactured with thermo-stamping process. Second, the...

As a class of effective lightweight energy absorption materials, periodic closed-cell foams have been widely applied in engineering, in which the Kelvin and Octet-B foams have demonstrated great value in the research of multiaxial mechanical characteristics. For this reason, this study aims to develop a series of realistic finite element analysis (...

Additive manufacturing (or 3D printing) for continuous fiber composite exhibits great potential for fabrication of next-generation lightweight sophisticated structural components. Nevertheless, understanding of interface characteristics of printed parts has remained an open research question for broader applications of this new technology in engine...

Thin-walled structures constructed of fiber reinforced composites are increasingly being employed in engineering practice. However, there is limited investigation into their residual properties after high temperature and hygrothermal aging. The aim of this experimental investigation is to study how moisture absorption and high temperatures affect t...

Fused deposition modeling (FDM) has demonstrated its effectiveness in the additive manufacturing (AM) field thanks to its numerous merits, such as low cost and ease of implementation. Polymeric polylactic acid (PLA) has been widely used in FDM attributed to its recyclable, renewable, degradable and biocompatible characteristics. However, the materi...

High-speed three-dimensional digital image correlation (3D-DIC) techniques can acquire full-field vibration responses under a single excitation, which is not restricted by the number of degrees of freedom (DOFs) in measurement compared with accelerometers and laser Doppler vibrometers (LDVs). Therefore, 3D-DIC exhibits compelling capacity in dynami...

Vision-based damage detection in carbon fiber-reinforced plastic (CFRP) composites can be interfered by such factors as surface texture, stains and lighting. A digital image correlation (DIC) based surface strain monitoring technique, on the other hand, enables to track the change of strain distribution. It is promising to develop a new approach fo...

Fatigue failure is one of the main causes of structural failure. Fatigue failure mechanism signifies a critical research issue for better design of the joined parts to enhance endurance and longevity. This study aims to explore the failure mechanisms of a CFRP/aluminum adhesive joint, in which DIC technique is used to record fatigue process in real...

Lightweight materials and structures have attracted tremendous interests for their compelling advantages in a range of engineering problems that have placed heightened requirements in safety, environment, competitiveness and cost over recent years. As an effective approach, hybrid systems aim to take advantages and characteristics of different mate...

Phase field approaches have been developed to analyze the failure behavior of ductile materials. In the previous phase field models, a constant critical energy or strain threshold is commonly introduced to the formulation of the driving force, aiming to avoid damage initiation at a low level of elastic and plastic deformations. However, it may not...

Bio-inspired thin-walled structures have gained growing interests attributed to their excellent performance of energy absorption and lightweight. This study proposes a novel energy absorber by mimicking the structural characteristics of animal long bone, namely bio-inspired multi-cell tube (BIMCT), which comprises laterally-graded multi-cell config...

Helmet is the most common and effective means to avoiding severe injuries of human head in accidents. Nonetheless, the helmet may not completely protect the head and head injuries can still happen under impacts. To improve the protectability of helmets, this study aims to systematically investigate the impact characteristics (e.g., helmet structura...

Low-velocity impact (LVI) on continuous fiber reinforced thermoplastics (CoFRTPs) has been extensively studied with a focus on single material. Impact characteristics and optimal design of hybrid CoFRTPs have not been well addressed even though they are of considerable advantages in balancing cost and performance. This study aims to develop design...

This study aims to characterize the mechanical behavior of a carbon fiber reinforced plastics (CFRP)/aluminum (Al) adhesive bonded single lap joint (SLJ) subjected to transversal three-point bending load with different adherend materials and kinematic boundary conditions. The experimental results divulged that the boundary conditions had noticeable...

Polymethacrylimide (PMI) foam materials exhibit great potential in engineering applications due to their lightweight property. Nevertheless, there is lack of constitutive data on the PMI foam materials under complex loading conditions; therefore, this paper reports the systematic experimental characterization of the elastic, plastic and fracture pr...

Cohesive zone model (CZM) has been extensively applied in numerical simulation of interfacial fracture behaviors such as composite delamination and fracture of adhesive joints. Accurate and efficient identification of CZM parameters signifies an important research topic to enable reliable analysis and design of these structures. This paper aims to...

A considerable number of surrogate-assisted evolutionary algorithms (SAEAs) have been developed to solve expensive optimization problems (EOPs) with continuous objective functions. However, in the real-world applications, we may face EOPs with discontinuous objective functions, which are also called EOPs with discontinuous responses (EOPDRs). Indee...

Pedestrian lower-leg protection and lower-speed crashworthiness often present two important yet competing criteria on the design of front-bumper structures. Conventional design optimization is largely focused on a single loading condition without considering multiple impact cases. Furthermore, design of front-bumper structures is usually discrete i...

Fiber metal laminates (FMLs) comprised of metal alloy and composite materials have been extensively applied in a broad range of engineering structures in virtue of their outstanding functional characteristics and cost benefits. This paper provides a comprehensive review on the state-of-the-art of the impact characteristics of fiber metal laminates...

Lower extremity is the most frequently injured body region in a pedestrian–vehicle impact. To evaluate lower extremity injuries, both the Flexible Pedestrian Legform Impactor (FlexPLI) and the Flexible Pedestrian Legform Impactor with Upper Body Mass (FlexPLI-UBM) have been used in practice. In general, UBM would have considerable influence on the...

Majority of existing design optimization of bumper systems has focused on one single impact loading case in literature, which may not offer proper performance under other loading cases. This study aims to address this issue by developing a multiobjective optimization approach, in which multiple impact loading scenarios are considered to optimize th...

This study proposes a machine learning (ML) based approach for optimizing fiber orientations of variable stiffness carbon fiber reinforced plastic (CFRP) structures, where neural networks are developed to estimate the objective function and analytical sensitivities with respect to design variables as a substitute for finite element analysis (FEA)....

This paper presents a combined experimental and numerical study on the low-velocity impact behavior of honeycomb-core sandwich panels with different structural parameters, including facesheet thickness, core height, honeycomb cell size, and cell wall thickness. Impact tests were conducted at four different energies using a drop-weight impact facili...

This paper reports an experimental investigation into mechanical behaviors and failure mechanisms of different joint methods for dissimilar materials, including adhesive joints, rivet joints, and hybrid joints with adhesive and rivet. In this study, a series of quasi-static tensile tests were conducted for different joint methods. The digital image...

As a highly promising lightweight material, carbon fiber reinforced plastics (CFRP) composites have been widely used in aerospace, marine and automotive industries, which could expose to low or high thermal environments with varying material properties. This study investigated the effects of temperature variation ranging from −30 °C to 160 °C on te...

This study aims to develop a novel approach to characterizing fracture parameters of cracked structures made of composite laminates and brittle adhesive joints by using digital image correlation (DIC) and virtual crack closure technique (VCCT). The parameters of mixed-mode fracture can be identified properly using the present method, which allows c...

As an effective optimization tool for expensive optimization problems (EOPs), surrogate-assisted evolutionary algorithms (SAEAs) have been widely studied in recent years. However, most current SAEAs are designed for continuous/combinatorial EOPs, which are not suitable for mixed-variable EOPs. This article focuses on one kind of mixed-variable EOP:...

While prosthetic devices have been extensively used to treat a wide range of human diseases and injuries, failure of these devices due to fatigue under cyclic loading has been recognized as a primary concern on therapeutic longevity. Experimental testing has long been a dominant approach to characterizing the fatigue behavior of prosthetic devices....

In this paper, a recently-developed phase-field damage model is incorporated into the topology optimization framework to take into account crack initiation and propagation in a path-dependent fashion. The proposed topological design can enhance fracture resistance of structures made of brittle materials such as advanced ceramics. For the first time...

This study aims to develop an effective method to identifying modal parameters of vibrating structures using digital image correlation (DIC) technique, in which singular value decomposition (SVD) and nonlinear least square iteration are integrated. The proposed approach was first used to measure modal parameters of a cantilever plate to verify its...

The original article contained typographical errors that a number of double brackets.

How to take full advantages of the strong designability of plain woven carbon fiber fabric is a key problem urgently needed to be solved in the application of plain woven carbon fiber fabric reinforced thermoplastics (PW-CFRTPs). This study explored formability of plain woven carbon fiber fabric experimentally and numerically through stamping proce...

This study aimed to investigate the influences of stamping temperature (or molding temperature) on thermal properties of matrix, mesoscopic structures of fabric and effective macroscopic mechanical properties of composite materials through experimental characterization. The plain woven carbon fiber/polypropylene composite laminates were prepared by...

This study develops a topology optimization approach for design of carbon fiber reinforced plastic (CFRP) laminated components with different failure criteria to reduce the risk of structural failure. The discrete material and thickness optimization (DMTO) method is presented to parameterize the design variables of thickness and orientation of CFRP...

In engineering practice, most design criteria require time-consuming functional evaluation. To tackle such design problems, multiobjective Bayesian optimization has been widely applied to generation of optimal Pareto solutions. However, improvement function-based expected improvement (EI) and the hypervolume improvement-based lower confidence bound...

Scaffold-based bone tissue engineering has been extensively developed as a potential means to treatment of large bone defects. To enhance the biomechanical performance of porous tissue scaffolds, computational design techniques have gained growing popularity attributable to their compelling efficiency and strong predictive features compared with ti...

This study aims to investigate the fatigue degradation of carbon fibre reinforced plastic (CFRP) composite and aluminum (CFRP/Al) adhesively-bonded joints after certain levels of transverse pre-impact. The CFRP/Al adhesive joints were tested post impact under quasi-static loading and different levels of cyclic loading to study fatigue behaviors. Ba...

Metal foams are commonly used to withstand impact loading from different directions in real life applications attributable to their superior performance of energy absorption to weight. It has been of special interest to explore the complex yield/failure behavior of metal foams under dynamic impact recently. However, existing studies have mainly foc...

Adhesive bonding techniques have been widely used and studied in automobile industry, enabling to join dissimilar materials, such as carbon fiber reinforced plastic (CFRP) composites and metals. However, durability of an adhesive joint is often a major concern in the severe service conditions of vehicle due to the nature of polymeric materials invo...

As one of widely-used multi-functional materials, metallic foams are often subjected to multiaxial stress states in their practical applications; in which the yield behaviors under different stress states need to be better understood. However, it is difficult to conduct multiaxial mechanical tests on foam materials, especially under arbitrarily pro...

This study aims to explore failure mechanism and failure criteria of carbon fiber reinforced polypropylene plastic (CFRPP) by presenting a novel notch-shaped design of specimens with two different fiber orientations (0/90)4 and (+45/-45)4 subject to stamping process under room temperature. Two forming limit curves/diagrams (FLCs/FLDs) were establis...

Auextic materials possessing negative Poisson's ratios have gained great research interest by virtue of its various exotic mechanical properties while most of these metamaterials rely on the hollow cellular configuration, largely undermining the overall mechanical performance. It therefore restricts their application in load-bearing engineering fie...

Phase-field methods for fracture have been integrated with plasticity for better describing constitutive behaviours. In most of the previous phase-field models, however, the length-scale parameter must be interpreted as a material property in order to match the material strength in experiments. This study presents a phase-field model for fracture c...

Aluminum foam, carbon fiber reinforced plastics (CFRP) and foam-filled structures have been drawn growing attention for their outstanding lightweight and energy absorption capacity; therefore, crushing characteristics of a hybrid system involving these components would be of particular interest. In this study, quasi-static compression tests were ca...

This study aimed to investigate low-velocity impact responses and crashworthiness of different aluminum foam-core sandwich structures. Several drop-weight dynamic impact tests were first conducted on both sandwich structures and their individual components to explore the mechanism of energy absorption and interactive effect between the foam core an...

To improve the lightweight and crashworthiness in vehicular engineering, there has been growing interests in metal/composite hybrid configuration, which is relatively newer than traditional metallic or composite structures. It is of vital importance to understand lateral crushing behaviors of hybrid system to gain maximum benefits from the structur...

This study aims to explore the crushing behavior of aluminum (AL) - carbon fiber reinforced plastic (CFRP) tubes with different hybrid configurations subjected to quasi-static and dynamic loading conditions. First, a series of experimental tests are carried out to explore the crushing behaviors of hybrid tubes in comparison with the corresponding i...

Thin-walled composite structures are increasingly used in vehicles attributed to their lightweight and high energy-absorbing capacity. However, understanding crushing behavior of tubal structures made of different materials for lateral impact loading from different directions is fairly limited, which restricts their further applications. This study...

Design of vehicle frontal structures signifies an important topic of studies on protection of pedestrian lower extremity. Conventional optimization has been largely focused on continuous variable problems without involving complexity of human model. Nevertheless, design of frontal structures is commonly discrete from a manufacturing perspective and...

Basalt fiber composites have attracted increasing attention in recent years due to their advantages over carbon fiber composites in many aspects such as lower cost, environmental friendliness, superior heat resistance and ductility. Notches in structural components are unavoidable in practical applications. In the present study, the effects of notc...

This study aims to develop an inverse approach to identifying the cell-wall material properties of closed-cell aluminum (Al) foams, which is based upon indentation tests, numerical simulation and optimization technique. Vickers nano-indentation tests are conducted on the cell-wall of foams, and the residual surface deformation is measured by a high...

This study aims to characterize the crushing responses of hat-shaped composite tube under quasi-static three-point bending (TPB) and transverse compression (TC) conditions. The specimens were fabricated with different stacking configurations considering the effect of ply number, ply angle (containing [±45°] layers) and interply hybrid structure (sa...

As a class of promising cost-effective lightweight structures, metal-composite hybrid structures has rapidly emerged in automotive industry largely attributable to their outstanding multifunctional and crashworthy characteristics. Recently, continuous efforts have been devoted to the studies on the crashworthiness of various hybrid tubes, which com...

This paper is aimed to study the vehicle front-end structural design and provides the robust optimal method for engineering problem involving discrete design variables. First, the simulation model of SUV is constructed and the validity of the model is conducted by physical test. Then, the study is carried out by utilizing the successive Taguchi met...

Fracture is one of the most common failure modes in brittle materials. It can drastically decrease material integrity and structural strength. To address this issue, we propose a level-set (LS) based topology optimization procedure to optimize the distribution of reinforced inclusions within matrix materials subject to the volume constraint for max...

Inspired by metal forming tests, the conventional forming limit diagram (FLD) was employed to characterize the forming properties of the Glass Fiber Reinforced Polypropylene (GFRP) composite in this study. The strain history of GFRP specimens was captured by using a 3D digital image correlation (DIC) system. Since the conventional metal FLD is esta...

Mechanical failure of zirconia-based full-arch implant-supported fixed dental prostheses (FAFDPs) remains a critical issue in prosthetic dentistry. The option of full-arch implant treatment and the biomechanical behaviour within a sophisticated screw-retained prosthetic structure have stimulated considerable interest in fundamental and clinical res...

Biomaterials have been extensively used in prosthetic applications for their proven biocompatibility and osseointegration characteristics. Nevertheless, one of the critical issues of some synthetic biomaterials is brittleness prone to experience fracture failure due to low tensile strength and low fracture toughness. This study aims to employ a rec...

In engineering practice, most optimization problems have multiple objectives, which are usually in a form of expensive black-box functions. The multiobjective efficient global optimization (MOEGO) algorithms have been proposed recently to sequentially sample the design space, aiming to seek for optima with a minimum number of sampling points. With...

Structural responses, deformation modes, blast resistance and energy absorption of foam core signify some major functional characteristics for design of sandwich panels. This study aimed to address these issues by investigating uniform and graded foam core configurations. First, an experimental study was performed and the testing results of blast-l...

This work investigates the effects of carbon/glass/basalt hybridization and fabric structure on the low velocity impact resistance of fibre reinforced plastic composites. Interply hybrid specimens used in the study were fabricated in a sandwich-like stacking sequence using a vacuum assisted resin infusion molding technique. Low velocity impact test...

This paper aims to evaluate the influences of impact-induced damage on the residual flexural strength of honeycomb core sandwich panels with different structural configurations by combining the experimental, numerical and theoretical methods. Low-velocity impact tests and three-point bending tests after impact are carried out to determine and quant...

This paper aims to investigate the low-velocity impact behavior of fiber metal laminates (FMLs) consisting of carbon fiber-reinforced layers and aluminum sheets under multiple impacts with the same total energy. Experimental and numerical methods are implemented to explore the influence of impact energy division, load sequence and metal layer distr...

Performances of lightweight sandwich panels can be enhanced by proper combination of facesheets and core. To promote sandwich structures for automobile applications, this study aimed to investigate the crashworthiness and residual performance of metallic foam based sandwich panels. Three types of facesheet materials (i.e. aluminum alloy Al6061, gla...

This paper introduces a novel hierarchical core structure to sandwich panel for bearing the blast loading, in which each vertex of a regular hexagonal cell was replaced with a smaller hexagonal unit. The finite element (FE) models of such hierarchical honeycomb sandwich panels were established and validated with the experiments under different impu...

This study investigates the interply hybridization of carbon fibre reinforced polymer (CFRP) composite laminate to improve the flexural performance and cost efficiency. Carbon layers were replaced partially by basalt and/or glass fibres to explore the effects of hybrid ratio and stacking sequence on the flexural behavior and material usage. Hybrid...

Associated code (ABAQUS subroutines) of the following paper: Fang, J., Wu, C., Rabczuk, T., Wu, C., Ma, C., Sun, G. and Li, Q., 2019. Phase field fracture in elasto-plastic solids: Abaqus implementation and case studies. Theoretical and Applied Fracture Mechanics, 103, p.102252.

Multicell columns have becoming increasingly attractive in crashworthiness applications due to their high efficiency of material utilization. Meanwhile, an urgent need exists to develop new structures to achieve the aim of light weight without sacrificing crashworthiness. A novel multicell column with axially-varying thickness (AVT) is proposed in...

The existing studies on thin-walled structures have focused on structural optimization mainly for enhancing crashworthiness and lightweighting, whilst relatively little attention has been paid to analysis of cost efficiency of an optimized structure. How to develop cost-effective products has always been a primary goal pursued by enterprises in dif...

Phase field modelling for fracture has been extended from elastic solids to elasto-plastic solids. In this study, we present the implementation procedures of a staggered scheme for phase field fracture of elasto-plastic solids in commercial finite element software Abaqus using subroutines UEL and UMAT. The UMAT is written for the constitutive behav...

The present study aimed to explore the effects of impact surface and impact energy on the residual characteristics of the carbon fiber reinforced plastics (CFRP) / aluminum (Al) adhesive bonded joints. The adhesive specimens were manufactured in the hot pressing machine with specific curing temperature and curing pressure of the adhesive. In the ex...

An implicit numerical integration algorithm is presented for the unified yield criterion, which could encompass most other yield criteria. The modification matrix, which is used to convert the continuum tangent modular matrix into the consistent tangent modular matrix, is derived for the return to planes, lines, and the apex of the unified yield cr...

The adhesive joints connecting carbon fiber reinforced plastic (CFRP) composites with aluminum alloy (Al5182) could experience multiple impacts at different rates from different directions in service. However, there has been no study available in the open literature concerning the axial residual performances of the CFRP/Al5182 adhesive single-lap j...

The phase field modelling has been extended from brittle fracture to ductile fracture by incorporating plasticity. However, the effects of plastic yield functions and hardening on the fracture behaviour have not been examined systematically to date. The phase field fracture coupled with multi-surface plasticity is formulated in the variational fram...

To meet the growing demands for structural lightweight and safety, metal-foam-composite hybrid tubular sandwich structures, which combine low-cost metallic materials and high-strength composites with low-density cellular materials, have been recently introduced to be a class of energy absorber configurations for automotive engineering. This study p...

The stiffened plates are of demonstrable advantages and potential in offering high resistance to such extreme loading scenarios as blast. Since the distribution of the stiffeners has considerable effect on their performance, its design signifies an important topic of research. However, existing research has mainly focused on empirical design, and t...

Objectives: This study aimed to develop a simple and efficient numerical modeling approach for characterizing strain and total strain energy in bone scaffolds implanted in patient-specific anatomical sites. Materials and methods: A simplified homogenization technique was developed to substitute a detailed scaffold model with the same size and eq...

Sandwich panels with an energy-absorbing core material have exhibited great potential in lightweight structures for blast protection. In this study, the deformation/failure modes of sandwich panels against blast impulse were investigated experimentally. The blast tests were conducted on the aluminum foam-core sandwich panels with different faceshee...