For the past six years, we have been benefiting from the discovery by [1] that the trace of the plane stress stiffness matrix (tr(Q)) of an orthotropic composite is a fundamental and powerful scaling property of laminated composite materials. Algebraically, tr(Q) turns out to be a measure of the summation of the moduli of the material. It is, therefore, a material property. Additionally, since tr(Q)

Mechanical properties of composite laminates can be tuned by either tailoring ply orientations or by using ply drops to change thickness profiles. The latter cause resin-rich pockets to form in thermoset composites that are autoclave cured after lay-down. This paper focuses on the morphology of ply drop regions with carbon fibre thermoplastic composites manufactured using in-situ consolidation with

The influence of the hygrothermal effect is considered in the constitutive relation of carbon fiber reinforced composite (CFRP) based Reddy’s high-order shear deformation theory. The geometric nonlinear governing equations are derived by using virtual displacement method; and the boundary conditions are elastic restraint against rotation. Then, the physical parameters of CFRP are considered as constant

The aim of this work is to study the nonlinear creep response of polymeric composites under humid environments. A three-dimensional orthotropic nonlinear creep constitutive model that considers the moisture effect is derived by introducing the moisture shift factor into Schapery’s nonlinear equation. Hygrothermal-mechanical coupling moisture absorption tests, as well as static mechanical property tests

In this paper, a machine learning-based approach has been proposed to integrate artificial intelligence during the designing of fiber-reinforced polymeric composites. With the help of the proposed approach, an artificial neural network (ANN) model has been developed to achieve the targeted filler content for cotton fiber/polypropylene composite while satisfying the required targeted properties. Previously

Phase-Field (PF) methods of fracture have emerged as powerful modeling tools for triggering fracture events in solids. These numerical techniques efficiently alleviate mesh dependent pathologies and are very suitable for characterizing brittle as well as quasi-brittle fracture in a wide range of engineering materials and structures including fiber reinforced composites. In this work, a multi phase-field

Many unwanted defects such as burr and delamination can be induced due to the high cutting forces in the machining process of carbon/carbon (C/C) composites due to their brittle property. In this regard, it is necessary to predict the cutting force accurately in the machining of C/C composites. In this paper, a prediction model of dynamic cutting force in time domain is proposed for transverse orthogonal

The mechanical behavior of sandwich panels with a buckling-dominated lattice core (SPBLC) are studied in this work. Based on an analysis of the structural force, deformation, yield point, plastic limit, and bifurcation buckling, the formulas for predicting the structural stiffness and strength are established and then validated by experimental tests and numerical simulations. The negative effects of

In this paper, the nonlinear bending analysis of Functionally Graded Porous (FGP) beams is investigated using an efficient numerical algorithm associating a meshless collocation technique uses the Multiquadric Radial Basis Function (MQRBF) approximation method and a higher-order Taylor series-based continuation procedure. Material properties of the FGP beams are described by adopting a modified power-law

In the present work, an innovative two-phases local/nonlocal constitutive mixture model based on the stress-driven model for free vibrations problems is presented. The above two-phases model has been formulated by defining a convex combination of local/nonlocal phases through a mixture parameter and the closed form solution for free vibrations problems is given. The proposed local/nonlocal model has

For given mechanical properties of the fiber and the matrix, and their volume fractions, we first numerically, using the finite element method, find values of the elastic moduli and the diffusivity of the homogenized unidirectional (UD) lamina. However, values of material parameters appearing in the Hashin failure criteria for a lamina and in the cohesive zone model for simulating delamination between

In this paper, the buckling of cross-ply and angle-ply composite beams under hygro-thermo-mechanical loading is presented by the analytical approach. This approach is based on theory of hyperbolic refined shear deformation. This approach which has strong resemblance with beam theory of Euler Bernoulli in various aspects, accounts for a second-degree variation of the transverse shear strains through

Multiscale techniques have been widely shown to potentially overcome the limitation of homogenization schemes in representing the microscopic failure mechanisms in heterogeneous media as well as their influence on their structural response at the macroscopic level. Such techniques allow the use of fully detailed models to be avoided, thus resulting in a notable decrease in the overall computational

Carbon fibre reinforced polymers (CFRP) are suitable materials for high-end applications due to the high strength to weight ratio. This important advantage counteracts to their machinability because the inherent anisotropy and the heterogeneity lead a high difficulty to reach good quality in terms of surface integrity, dimensional and geometrical tolerances. Hereupon, this paper determines the effect

In this paper, a novel nonlocal strain gradient isogeometric model using the nonlocal strain gradient theory (NSGT) and isogeometric analysis (IGA) is developed to analyze free vibration and bending behaviors of functionally graded (FG) plates. Based on the higher-order shear deformation theory (HSDT) and NSGT, the weak form of the governing equation motion of the plates is presented. To homogenize

This research is geared towards the improvement of the dynamic response of the corrugated sandwiched composite structures under low-velocity impact. A novel glass fibre reinforced double-corrugated sandwiched composite (DCSC) structure was designed and was manufactured by using a vacuum assisted resin infusion (VARI) technique. The lattice core of the DCSC was formed by crosslinked composites as reinforced

This paper investigates for the first time the effect of blending hybrid steel-polypropylene fiber (SF-PF) and coarse aggregate (CA) on the stress-strain behavior of ultra-high performance concrete (UHPC) under uniaxial compression. The uniaxial compression tests of UHPC specimens were carried out for different SF-PF, CA dosages and PF aspect ratios. Results show that the addition of hybrid SF-PF not

Thin unidirectional-tape and woven-fabric composites are widely utilized in the aerospace and automotive industries due to their enhanced fatigue life and damage resistance. Providing high-fidelity simulations of intra-laminar damage in such laminates is a challenging task both from a physics and a computational standpoint, due to their complex and largely quasi-brittle fracture response. This is manifested

The ballistic performance of ultra-high molecular weight polyethylene (UHMWPE) laminated plates and UHMWPE encapsulated aluminum structures were numerically characterized. Full three-dimensional continuum model for each type of target was built, and the UHMWPE was simulated using a sub-laminate approach with a composite material model. Simulation results were compared with existing experimental measurements

The beam opening (BO) technique, which involves (1) the creation of a web opening in the beam to weaken its flexural capacity and (2) the fibre-reinforced polymer (FRP) shear strengthening around the opening to avoid shear failure of the beam, was proposed to realize the strong column-weak beam hierarchy in existing reinforced concrete (RC) frames, which were designed using previous codes and thus

Adhesive joints with composite adherends have been widely applied in the automotive and aerospace industry. The demands on high performance adhesive joints highlight the importance of understanding their respective fracture mechanisms. In this paper, single-lap joints (SLJs) bonded with a brittle and a tough adhesive were manufactured and tested, respectively. Experimentally, the fracture mechanisms

In this paper, the low velocity impact (LVI) on a quasi-isotropic laminate [45/0/–45/90]3s (QIL) is studied to predict the deformation response and damage state of the laminate. This stacking of a QIL is a benchmark case that results in a “rotating-fan” pattern of delamination damage due to the impact. Drop-tower tests were performed with an impact energy of 25 J and an impactor mass of 7.5 kg. 3D

The fabrication of carbon fibre-reinforced polymer (CFRP)-based shape memory alloy hybrid composite (SMAHC) beams is highly challenging because conductive carbon fibres alter the electrical characteristics of the beams when driven by an electrical current. Here, we propose and fabricate a CFRP-based SMAHC beam with embedded SMA actuators using the electrical insulation methods. We firstly implemented

The use of adhesively-bonded CFRP crack-patching in old metallic bridges seems to be a promising fatigue strengthening technique, but the internal laminar structure of puddle iron could influence its efficiency, resulting in premature interlaminar failure within the metal before CFRP debonding. To investigate the fatigue behaviour of this retrofitting system, six double-strap joints with CFRP laminates

Many current materials and structural systems are layered. The structural performances of these multilayered systems are dependent on interfaces, the presence of which is inherent to them. A methodology for the simplified stress analysis of such structures under 1D-bar kinematics is presented. The macro-element technique is used to solve the set of ordinary differential equations involved. A dedicated

This study intends to model the effect of porosity type defect and analyze the consequences of porosity on the buckling characteristic of various types of FGM sandwich combinations. Here, we consider four types of FGM sandwich combinations considering the multiple arrangements of the constituent layers (i.e., two face sheets and a core). Further, the combinations of all kinds of sandwiches are considered

Design optimization of moderately thick hexagonal honeycomb sandwich plate has been investigated via employing an improved multi-objective particle swarm optimization with genetic algorithm (MOPSOGA). Based on the first-order shear deformation theory (FSDT), governing equations of the plate are obtained. The equations are solved analytically. Total weight and maximum deflection of the plate under static

Metal inserts are occasionally used to improve bearing load capacity of bolted joints in laminated composite materials. This paper investigates a new reinforcement concept where inserts are built by locally replacing composite plies with metal patches of various diameters at the hole perimeter. The inserts are built during composite manufacturing by alternately placing the metal patches through the

Additive manufacturing offers new design opportunities for composite sandwich structures. The work presented herein builds on the concepts of the coating approach for topology optimization of shell-infill structures by using density gradients to determine local material orientations. A generalized material property interpolation scheme is presented and the sensitivity analysis for the minimum compliance

The hexagonal braiding is a novel 3D braiding technique that can generate a large family of complex fiber architectures for composite preforms. In order to fully exploit this technology, a fiber architecture based model was constructed connecting the braiding process parameters with the resulting fabric structures through machine emulation. First, an oblique coordinate system is established according

The purpose of this paper is to investigate the failure mechanisms of carbon fiber reinforced composites (CFRP) single-lap bolted, bonded and hybrid bolted/bonded joints during compression. The failure process and the failure mechanisms of the compression tests were analyzed using field emission scanning electron microscope (FESEM) and acoustic emission (AE) technique. A novel method is proposed to

In this article, by means of nonlocal elasticity theory with using a higher order shear deformation theory (HSDT), the size-dependent wave propagation in functionally graded (FG) doubly-curved shells is investigated. In this HSDT, an exponential function along with a trigonometric formula represents the displacements and the implementation of Hamilton’s principle resulted in obtaining the governing

Out-of-plane failure is common in composite layered materials. Its detection in numerical simulations usually involves a high-level of spatial refinement which may lead to an excessive computational time for large structures. This paper presents a formulation for the recovery of the transverse stresses in conventional linear shell elements based on First-Order Shear Deformation Theory. Starting from

In this study, the dynamic buckling of bi-directional functionally graded porous (BD-FG) truncated conical shell resting on an elastic foundation is investigated for different boundary conditions. The structure is under an axial compression loading at the two ends. First order shear deformation theory (FSDT) and Hamilton's principle are used to derive the governing equations. The material characteristics

Composite materials are increasingly used as structural components in military and civilian aircraft. To ensure their high reliability, numerous non-destructive testing (NDT) techniques have been used to detect defects during production and maintenance. However, most of these techniques are non-automatic, with diagnostic results determined subjectively by operators. Some deep learning methods have

Herein, the damage problem of quasi-isotropic composite laminates subjected to a quasi-static transverse load has been studied analytically. The damage was modeled as multiple equal-sized annular delaminations of equal-interval in the thickness direction without any opening during transverse loading. This simplified damage shape was adopted according to the typical damage morphology of impact-tested

A neural network enhanced system containing a subsystem with one or multiple neural networks is proposed. Instead of defining the loss function as the direct output of a neural network model, the proposed method uses the system output, which can be measured from experiments, to define the loss function. The loss function is contributed by the outputs from one or multiple neural network models through

This paper studies the nonlinear free and forced vibrations of fluid-conveying pipes that are made of porous functionally graded materials and supported on nonlinear elastic foundation. A modified power-law function is adopted to model the porous functionally graded materials, with both even and uneven porosity distributions to represent different material imperfections. Equations of motion of the

The paper investigates the processing technology and mechanical properties of a novel type of 3D-braided composite material, named as one-carry-two full five directional braided composite (1C2 3DF5d). The material differs from the conventional 3D-braided composites by doubling the number of braiding yarns in the cross section. This unique yarn architecture is achieved by the introduction of a novel

Efficient joining of hybrid thermoset/thermoplastic composite joints is critical to produce high performance lightweight structures while keeping the cost low. Herein, a high-power UV-irradiation technique was proposed to rapidly active the surfaces of PEEK and PPS composites for the following co-cure joining with epoxy composites. A single lap-shear joint test and a double cantilever beam test were

Wire mesh interlayers are introduced to fabricate high interface strength metal-polymer-metal sandwich panels. While resistance welding is used to join metal sheets to wire mesh at predesignated spots, vacuum hot pressing is used to infuse polymer into the wire mesh. Peel strength for fabricated sandwich panels is seen to be around 300% higher than that for adhesive joints reported in literature. Since

All-metallic sandwich panels with lattice truss cores are typically ultralight, stiff and strong, yet poor in passive vibration damping. Novel laser-welded corrugated-core (LASCOR) sandwich panels with polyurea-metal laminates (PML) as face sheets were proposed and fabricated, and their vibration and damping characteristics were systematically investigated, both experimentally and numerically. Frequency/time

One of the key enablers of valued early decision-making in composite material designs is the ability to account for different aspects/scale of uncertainties within models and design processes. In order to enable well-judged decisions and to improve the trust of industrial decision-makers, measures of uncertainty, risk, and cost involved in materials are crucial. In this work, we provide i) efficient

This study presents a numerical mesoscale approach to simulate the damage and failure mechanism of woven laminated composites under low velocity impact loading conditions. First, measurements were made on samples to obtain a realistic reproduction of the microstructure. This allows relating failure mechanisms in composite laminates with their geometry and topology. A three-dimensional Hashin criterion

The function of the metamaterials is determined by the configuration and spatial arrangement of the lattice microstructure. Once manufactured, the geometry and function of the metamaterials are irreversible and cannot be adapted to the environment to be variable and adjustable. This paper studies a shape-reconfigurable, functionally deployable, mechanically adjustable and reusable intelligent multi-stable

The present study pertains to the linear multiple regression analyses on a database of 185 hinged-beam experiments on FRP bars. The database was compiled from 51 tests conducted within the scope of the present study and 134 tests conducted by previous researchers. Bond strength and development length equations, taking different types of FRP bars and surface finishes into account, were developed and

The composite sandwich structures, as a representative of lightweight and high-strength structures, exhibit extraordinary engineering application potential. However, the weak connection between panel and core limits their application. This paper focuses on investigating the panel-core connection and impact properties of the carbon fiber reinforced polyether ether ketone (CF/PEEK) sandwich structure

The challenge associated with the use of polyvinyl chloride (PVC) plastic pipelines is to improve their structural integrity without increasing their cost. Currently, PVC pipelines are the most cost-effective method of transporting water and sewage drainage. However, their low deterioration and mechanical properties cause significant losses and sacrifice the structural integrity of pipelines. Therefore

Because it lacks sufficient descriptive power regarding the appropriate scale effect, conventional continuum mechanics is not applicable to the rapidly developing field of micro-nanoscale structures and devices. To accurately describe the scale effect on multi-scale structures, a number of high-order medium theories have been developed, with micropolar theory being the most prominent. However, because

The studies on the higher-order beam theory and its application to functionally graded (FG), laminated composite and sandwich beams have received much research attention over recent years. While significant progress has been made, there is an issue with the selection of the appropriate distribution function for describing section warping due to transverse loading. In the present study, a rational approach

During the helical milling of carbon fibre reinforced polymer(CFRP)/Ti laminated structures,there are inevitable influences between the CFRP and Ti. This paper investigated the effect of Ti on hole quality in CFRP during the helical milling of a CFRP/Ti laminate. Cutting force and heat, as well as the surface and subsurface qualities of holes in CFRP, were observed with and without the presence of

This paper presents a detailed study on the development of axial, lateral and Von Mises strains measured by contact and non-contact methods under axial compression fiber reinforced polymer (FRP) confined and unconfined concrete specimens. The focus of the study was on the correlation between macro responses and localized deformations and the effects of FRP confinement on the localization of deformations

Carbon fiber reinforced composite is considered as a potential substitutes used in the lightweight of automotive engineering. Nevertheless, the high price and complicated manufacturing process remain challenges for the large-scale application of conventional carbon fibers. In this study, a novel plane isotropic composite reinforced by long carbon fiber non-woven is introduced, which overcomes the obstacles

Three kinds of sandwich beams were prepared, which were cross, double cross and square sandwich structure (CSS, DCSS and SSS), using spruce wood as face panels, KH-560 modified jute fabrics reinforced epoxy laminated composites (JFRELC) as cores. This research investigated the mechanism of micro-surface modification of composites, the bending behaviors and failure modes of sandwich structures. The

Crashworthiness plays a key role in energy absorption and hence in vehicle accidents. The energy absorption capacity of laminated composite materials is heavily investigated in the industry due to their low cost, corrosion resistance, and high strength to weight ratio. Thus, this paper experimentally investigates the effect of the addition of woven fiber laminates and fiber steel sandwich laminates

A separation-of-variable method was proposed in 2009 by the present authors and co-workers (Xing YF, Liu B. New exact solutions for free vibrations of thin orthotropic rectangular plates. Compos Struct 2009;89:567–74), but this traditional separation-of-variable method is incapable for free boundary conditions. Hence, this work is to improve the traditional separation-of-variable method to make it

A composite metamaterial honeycomb that exhibits sign-switching expansion coefficients has been introduced herein, in which at certain conditions the microstructures display resemblances of an ancient Islamic art. This is achieved by the use of two types of materials within each unit cell: a cross rod of very high expansivity and a frame linkage of insignificant expansivity. When the frame linkage

Interface plays a critical role in the mechanical performance of composites. Lack of a suitable interface design has long been a bottleneck impeding the full exploitation of the mechanical strengths of many superior reinforcement phases such as the high-performance carbon fibers and carbon nanotubes. Here a Floquet-based bar-spring model is developed to simulate the elastic and failure behaviors of

A design framework is here presented for the development of an architected solid with targeted mechanical properties thanks to an optimized porosity distribution. A 2D lattice of regular hexagons is considered as core element of a sandwich panel and a Bloch-Floquet-based approach is adopted to derive homogenized equivalent properties. The density distribution of the equivalent continuum is taken as

Spatio-temporally modulated composite metamaterials (STMCMs) possess tunable and nearly “full-banded” asymmetrical elastic wave properties, making them highly promising for uses in a wide range of applications, such as cloaking, acoustic information processing, ideal vibration isolation, ultrasonic technology. Despite much progress made in the structural design and fabrication of intelligent materials