Composite Material Plate Research Articles

Damage imaging method based on circular DE-IDT array for phased array data fusion

Plate-like structures, including composite material plates, are extensively employed in major engineering structures such as aerospace, high-speed rail, and civil engineering. The growing utilization of curved panel structures and the increasing complexity of these structures have emphasized the need for flexible sensors capable of efficient signal front-end reception. Addressing the limitations of conventional sensors made of brittle piezoelectric materials in adhering to the surface of structures for health monitoring, a self-developed flexible dielectric elastomer-interdigital transducer (DE-IDT) array is employed to achieve damage imaging in isotropic aluminum curved panel structures and orthotropic composite material plates using linear frequency modulation (chirp) signal excitation. In addition, a proposed fusion method is utilized to obtain weighted imaging results, and evaluation and analysis are performed using relevant indicators. Experimental findings highlight the improved imaging accuracy achieved through phased array data fusion using the linear chirp signal, attributed to its wideband characteristics and ability to capture more damage signals. Moreover, the effectiveness of the circular DE-IDT array for damage detection and imaging in curved panel structures and composite material plates is successfully verified.

A Thermodynamically Consistent Anisotropic Continuum Damage Mechanics Model With Damage-Dependent Equivalent Strain

Abstract This paper proposes a new thermodynamically consistent anisotropic continuum damage mechanics model that the degradation of material is described by a set of damage variables. We adopt a set of novel equivalent strains which are functions of both the strain and the damage state variables as well. A viscous stabilization method is considered to improve the convergence during the material softening. The evolution of damage state variables is updated through a Newton–Raphson iterative process. The expression of the consistent tangent stiffness matrix is also derived. A smoothed exponential damage evolution shape function with rescaling regularization method is proposed to describe the material softening process and the mesh dependency phenomenon is relieved. Several sets of numerical examples including three-point-bending of a notched beam, uniaxial tension of unnotched and notched plate of composite material with multiple layups are presented to verify the anisotropic damage models.

Research on fatigue performance of “sandwich metal-structured ” composite materials in ultra-low temperature environments

The aim is to investigate the influence of aluminum content in the FeCoCrNiAlx series high-entropy alloys, different aluminum alloy damping layers, and the thickness of damping layers on the fatigue performance of sandwich structure composite material plates after room temperature and low-temperature aging treatment. By using abaqus/fe-safe simulation, as well as liquid nitrogen low-temperature aging treatment and fatigue tensile testing, the differences in fatigue performance between composite materials treated with low-temperature aging and those untreated at room temperature were observed. The increase in aluminum content significantly improves the lifespan of the composite materials, and after low-temperature aging treatment, the change in strength is even more pronounced. Keeping the thickness and material of the upper and lower layers constant, the tensile life of the material, both untreated and treated at low temperatures, shows a significant increasing trend as the thickness of the middle damping layer increases. Other conditions being equal, the iMPact of different damping layer aluminum alloys on fatigue performance is also very evident. In terms of tensile cycles, the ranking is as follows: 7075 > 2A12 > 6061. After low-temperature treatment, the fatigue tension cycles of the 2A12, 6061, and 7075 damping layers under a force of 100 N are respectively 8.66, 7.43, and 2.01 times those of the untreated composite materials.

Protection performance of aluminum matrix ceramic ball composite materials plate for hypervelocity impact based on FE-SPH adaptive method

Space debris is a major threat to the safety of spacecraft in orbit, and advanced protective materials with lightweight and high impact resistance are effective passive protection solutions. In order to investigate the hypervelocity impact protection performance of aluminum matrix ceramic ball composite materials plate, this paper has carried out the hypervelocity impact test of aluminum matrix ceramic ball composite materials plate, and verified the accuracy of the numerical model based on the FE-SPH adaptive method, and then carried out a comparative study on the hypervelocity impact protection performance of aluminum plate and aluminum matrix ceramic ball composite materials plate with the same area density. The results show that: compared with the aluminum plate conditions, the composite materials plate has a better ability to broken the projectile. Compared with the aluminum plate, the kinetic energy absorbed by the composite materials plate is increased by 37.04%, and the kinetic energy of the generated debris cloud decreased by 69.57%. The proportion of the internal energy dissipation of the composite materials impact system reaches up to 72.03%. The secondary pollution generated by the composite materials plate is less and the hazardous debris have less threat to the rear wall. The research in this paper can provide reference for the selection of hypervelocity impact protection materials.

The features of interlayer fracture of composite materials with a variable layup angle under impact loading

Interlayer defects in structural components made of composite materials are caused by the imperfection of the manufacturing process, complex interactions of the constituents, and the effect of impact loads. The presence of these defects decreases the strength of such components and severely affects residual strength. The paper presents a numerical and experimental study of the behavior of a composite material plate with a variable layup angle under impact loading. Impactor velocities before and after multilayer plate perforation, as well as the dimensions of delamination-type defects, are determined experimentally. The Ansys LS-DYNA software in double precision mode is used to simulate the failure of composite plates under impact loading. It has been found that a significant contribution to the decrease in the impact energy is made by the delamination dimensions depending on the layup angle in the stack. The delamination area is related to the residual velocity of the impactor; namely, the larger the delamination area, the greater the decrease in the impactor velocity.

Transmission of Lamb wave in a micro-mechanically piezoelectric fiber-reinforced composite plate

The present work addresses the propagation characteristics of Lamb wave in a piezoelectric fiber-reinforced composite material plate. The considered plate is micro-mechanically modeled using the analytical techniques of the Strength of Materials and Rule of Mixtures. Secular equations are deduced for symmetric and antisymmetric modes of Lamb wave by employing suitable boundary conditions. The data of two distinct PFRC materials are taken into account, viz. PZT-5A-epoxy and CdSe-epoxy with different fiber volume fractions to investigate the latent characteristics of Lamb wave propagation. The amplitudes of dilatation and electrical potential of considered material are examined numerically and manifested graphically for both kinds of modes, i.e., symmetric and antisymmetric modes. The obtained graphical results are also compared for both kinds of modes. A comparative study has been carried out to exhibit the concealed characteristics of Lamb wave propagation for various distinct cases of considered structure for both symmetric and antisymmetric modes. The determined analytical results are in well agreement with the results present in the existing literature.

Study on the enhancement mechanism of ballistic properties of shear thickening fluid impregnated aramid fabric composite plates

AbstractThis study proposes a process for the preparation of composite laminates using the shear thickening fluid (STF) impregnated aramid fabric and presents some fabric panel configuration strategies. Firstly, this study prepared two kinds of STF using 20 nm and 500 nm silica particles. Then, the STF‐impregnated Kevlar fabrics were laminated and hot‐pressed to form the fabric panels. After that, the ballistic performance of the fabric panels was evaluated by firing the 9 mm steel core projectile using a gas gun. The ballistic tests showed that the ballistic performance of the hybridized configuration panels using STF‐20 treated fabrics as the front panels and STF‐500 treated fabrics as the backing panels was superior, with a reduction of 36.1%–37.6% in the number of perforated layers (4.7–5 layers) compared to a single STF‐treated panel. This study provides a new idea and method for applying STF in protective equipment.Highlights Shear thickening fluid (STF) and aramid fabric are better combined by hot pressing lamination process; The ballistic properties of fabric panels are significantly improved by hybrid configuration; The ballistic performance enhancement mechanism of composite bulletproof plate was revealed.

Acoustic Source Localization in Composite Plates using sideband peak count – Index Technique

In this study the Non-Linear Ultrasonic Sideband Peak Count-Index (SPC-I) technique is used as the foundation for anovel approach towards acoustic source localization (ASL) in orthotropic composite plates. The SPC-I based technique proposed here does not require the signal attenuation information or any knowledge on the time of arrival of the signal. It should be noted that since individual sensors can have varying sensitivities, the signal attenuation measured from the recorded signal amplitude is not very reliable. In addition, it is not necessary to have any prior knowledge of the mechanical properties of the composite plate material. All these are achievable by attaching 25 sensors that are well-scattered on the surface of the plate. The signals that are generated by an acoustic source are recorded by these 25 sensors. The recorded signals are then analyzed to derive the SPC-I value for each signal. The calculated SPC-I values are run through an optimization algorithm to predict the acoustic source location. Such localization is possible because the composite plate is inherently a non-linear material. Hence, as the signal travels longer distances through a composite plate, the recorded signal should show increasing level of distortion due to material non-linearity and dispersion. This phenomenon manifests itself primarily as a consequence of signal scattering and frequency modulation. Because of this, the phenomena of increasing distortion in the signal with increasing propagation distance can be exploited and utilized to predict the location of the acoustic source by solely utilizing the SPC-I values. This acoustic source localization technique is experimentally verified on a Carbon Fiber Reinforced (CFR) composite plate of dimension 500 mm x 500 mm with a thickness of 1 mm. The experimental results confirmed the feasibility of the proposed technique.

Development of a spread-tow fabric composite bipolar plate with fiber-spreading effect for vanadium redox flow battery

This study investigates a spread-tow fabric carbon/epoxy composite as an alternative to graphite bipolar plates in vanadium redox flow batteries. A spread-tow fabric composite can leverage the electrical and mechanical properties of conventional unidirectional and densely woven fabrics. Spread-tows can reduce the morphological effect of fiber tows on both properties by minimizing the height variation in the fabric and the generation of crimps, referred to as the fiber-spreading effect. The developed spread-tow carbon/epoxy composite bipolar plate with a 10 k spread-tow exhibited an area-specific resistance similar to that of a unidirectional fabric and lower than that of conventional 1 k and 3 k woven fabric composites. Furthermore, the tensile strength reached 762 MPa, approximately 85% higher than that of the unidirectional fabric composite. The spread-tow bipolar plate specimen demonstrated gas tightness for 100 h and achieved an energy efficiency of 81.18% without any damage or degradation during single-cell charge/discharge tests.

Results of a clinical trial of humeral neck osteosynthesis with carbon – carbon composite material

The metals utilized in the production of various implants in traumatology possess all the required mechanical properties. However, these materials are susceptible to oxidation. Carbon-carbon composites, on the other hand, exhibit X-ray transparency and are easily machinable. Thanks to their intricate yet essential physical, mechanical, and chemical properties, they find effective application in osteosynthesis and endoprosthesis procedures for bone structures. The aim of this study is to comparative view of the treatment outcomes for patients with fractures of the proximal part of the humerus by carbon-carbon composite material plates and titanium plates. Materials and methods. In this study, a carbon-carbon composite material plate was conducted osteosynthesis of the proximal part of the shoulder. In the comparison group, a titanium plate was employed. The study group comprised 20 patients, while the comparison group included 15 patients. The analysis of the results was carried out utilizing the Constant–Murley scale and the Quick DASH questionnaire. Results. A comparative study of treatment outcomes between the main and comparison groups revealed a more significant positive treatment effect in the group that underwent osteosynthesis of the humeral neck by a carbon-carbon composite material plate. This effect was observed at the 3-month, 6-month, and 12-month evaluation points. It was characterized by reduced shoulder pain, alleviated dysfunction manifestations, enhanced daily activities, and improved overall quality of life among patients in this group. Conclusions. The analysis of long-term treatment outcomes for proximal humerus fractures, utilizing both carbon-carbon composite material plates and titanium plates, by the Constant–Murley scale and the Quick DASH questionnaire, demonstrated statistically confirmed improvements in shoulder joint function for both treatment methods.

Delamination Detection and Localization in Vibrating Composite Plates and Shells Using the Inverse Finite Element Method.

Delamination damage is one of the most critical damage modes of composite materials. It takes place through the thickness of the laminated composites and does not show subtle surface effects. In the present study, a delamination detection approach based on equivalent von Mises strains is demonstrated for vibrating laminated (i.e., unidirectional fabric) composite plates. In this context, the governing relations of the inverse finite element method were recast according to the refined zigzag theory. Using the in situ strain measurements obtained from the surface and through the thickness of the composite shell, the inverse analysis was performed, and the strain field of the composite shell was reconstructed. The implementation of the proposed methodology is demonstrated for two numerical case studies associated with the harmonic and random vibrations of composite shells. The findings of this study show that the present damage detection method is capable of real-time monitoring of damage and providing information about the exact location, shape, and extent of the delamination damage in the vibrating composite plate. Finally, the robustness of the proposed method in response to resonance and extreme load variations is shown.

A Probable Approach to Reliability Assessment of Reinforced Plates

A scheme for solving the problem of determining the probability of failure and probabilistic (statistical) characteristics of the failure loading magnitude of a composite material plate is considered. The plate structure is a flat homogeneous matrix with stochastically distributed rigid rod inclusions. The geometric parameters of inclusions are considered independent random variables with given probability distribution laws. The expressions for the failure loading distribution function, the probability of failure, the mean value, and the dispersion of the failure loading were received and presented. Their dependence on the type of stress state, the inclusion number, and matrix Poisson’s ratio were studied graphically.

Study on Tensile Performance of Double-Bolted Joints between Carbon Fiber Reinforced Polymer Plate and Aluminum Plate

Carbon fiber reinforced polymer (CFRP) with high specific strength, specific modulus, and other outstanding properties, which could be used in aerospace, shipbuilding, and railway. The joint of carbon fiber composite material plate and metal material plate plays an important role in the overall performance of the structure. In this paper, a carbon fiber reinforced polymer (CFRP) progressive damage model is developed based on composite laminate theory and 3D Hashian theory. The model of the double bolt single lap joint shear connection is established for the CFRP plate and the finite element method is used to carry out the stress analysis and failure prediction of the lap structure. The effect on structural performance under tensile conditions was studied through the change of double bolt spacing. The results show that the decrease in bolt row spacing can lead to the interference effect between holes. In addition, the progressive damage of the composite plate is located near the center line of the bolt hole.

The role of intralaminar damages on the delamination evolution in laminated composite structures

Delamination is a major failure mode affecting laminated composite structures. This failure mechanism, if not properly monitored, can lead to uncontrolled cracks growth and premature structural collapse. Thus, predicting delamination propagation is mandatory to determine the structural integrity. At present, delamination has been extensively investigated in laminated composite structures but only a few studies have been performed on how the intralaminar damages influence the interfacial release energy and, consequently, the delamination evolution. In this paper, the well-established SMart-Time XB delamination simulation tool, has been coupled with a Hashin Criteria based User-Material Subroutine (UserMat) to study the role of the intralaminar damages in delamination propagation. A benchmark case based on the mixed-mode I/II Single Leg Bending (SLB) specimen for delamination evolution assessment under quasi-static loading has been investigated. Subsequently, a composite material plate, characterized by an artificial circular delamination, under compression has been considered. This study proved to be valuable by underlining the influence of fibre and matrix breakage on the interlaminar damages evolution. Interestingly, taking into account the effect of intralaminar flaws changes the local energy release rates values on the delamination front and, consequently, the crack shape and evolution.

A Symplectic-Spectral Element Method for High Frequency Vibration Analysis and Its Application in Structure-Borne Noise Prediction

The frequency-domain vibration model of the vehicle-track structure is established based on the symplectic-spectral element method (S-SEM). To this end, the vehicle is considered as 10-degree-of-freedom, and the rail is modeled by an infinite Timoshenko beam supported by discrete sprung fasteners. Further, the track slab and base plate are regarded as two-dimensional Timoshenko beams supported by uniformly distributed sprung elements. Using the pseudo excitation method (PEM), the track irregularity is viewed as the pseudo load. The vibration response and the internal force of the single-layer or multi-layer beam models are obtained by solving the corresponding S-SEM-based equations. The spectral forces are also applied in frequency bands to the finite element (FE) and statistical energy analysis (SEA) acoustic models. The steel-concrete composite bridge deck is simulated with composite plate materials. The effectiveness of the proposed method is verified by comparing the predicted results with those obtained from the field test. The achieved results reveal that multi-layer beam structures effectively consume energy, and elastic fasteners and steel springs are capable of effectively reducing bridge noise.

The effect of silica aerogel on thermal and sound absorption insulation properties of epoxy plate and glass fiber fabric epoxy composite

Silica aerogel (SA) is used as an additive in composite production to improve their thermal–mechanical properties, owing to their excellent properties such as high porosity, low density, and low thermal conductivity. All these unique properties make it attractive to be used for improving sound absorption and thermal insulation properties of composite materials. However, there are very limited studies on both improvement of sound and thermal insulation properties of glass fiber fabric epoxy composite by adding silica aerogel. With this aim, this study investigates the effect of incorporation of SA as a filler in glass fiber fabric epoxy composite (GFEC) and epoxy plate used in a wide variety of structural and engineering applications such as buildings, constructions, communication, aerospace and transportation, on sound absorption and thermal insulation. Results indicate that SA addition decreased the thermal conductivity coefficient from 0.55 to 0.48 W/mK for GFEC, and from 0.25 to 0.23 W/mK for epoxy plate, providing improvement on thermal insulation. Silica aerogel increased the maximum sound absorption coefficient (SAC) from 0.27 to 0.65, shifting the frequency from 4000 to 400 Hz for GFEC. The maximum SAC value increased from 0.28 to 0.41 at 800 Hz and decreased from 0.54 to 0.47 at 2000 Hz in SA incorporated-epoxy plate with 1 cm air gap thickness. The results reveal that SA has an improvement effect on low-frequency sound absorption for both GFEC and epoxy plate.

Sensor Distribution Optimization for Composite Impact Monitoring Based on AR Model and LPP

The aim of this article is to provide a sensor distribution optimization method for the effective impact monitoring of composite plates with fewer sensors. In this research, the number of sensors and the minimum difference between categories are used as objective functions I and II, respectively, where the minimum difference is the Euclidean distance between different influence categories. The dual objective functions are defined by means of finite element analysis, the autoregressive (AR) model, and locality−preserving projection (LPP). The sensor distribution is optimized based on Multi−Objective Particle Swarm Optimization (MOPSO). Finally, an impact monitoring method is provided, and an experimental platform is built to verify the method. According to the optimization results, different grid sizes have a certain impact on the identification results, with the smaller the grid size, the smaller the minimum difference between categories. Within a given grid size, the minimum difference between categories increases with the increasing number of sensors. Experiments show that the higher the number of sensors, the higher the recognition rate of the system. Comparing the experimental results with the energy analysis of wavelet bands and PCA methods, it is found that the method used in this study has a higher recognition rate. This research provides an impact monitoring method based on sensor distribution optimization. And the effectiveness of the method is verified by experiments. It provides a useful reference and choice for the structure condition monitoring of composite material plates.

Active vibration control of a piezoelectric composite laminate

An active vibration control method of the piezoelectric composite laminated plate under the external disturbance is studied. Firstly, the dynamic model of the piezoelectric composite laminated plate is derived based on the classical laminated plate theory and the Hamilton's principle. And subsequently, a sliding mode observer is developed for the external disturbance, and the stability of the observer is verified by the Lyapunov equation, and also the LQR controller is designed based on the observed state. The particle swarm algorithm is adapted to optimize the weighting matrix. In the end, the impacts of the geometric parameters and the stacking sequences on the dynamic behavior of the piezoelectric composite material plate is analyzed. Results indicate that the sliding mode observer can accurately track the original state, and the vibration of the piezoelectric composite material plate can be suppressed effectively by the LQR control based on the particle swarm

Reliability prediction of composite materials with random elastic inclusions

The object of the research is the construction of an algorithm that allows finding a number of strength (failure loading) statistical characteristics of a composite material plate under the conditions of a complex stress state. The relationships that determine the most probable value, mean value, dispersion and coefficient of variation of strength for an elastic homogeneous plate in which elliptical inclusions of another elastic material are uniformly distributed are written. Inclusions do not interact with each other and their geometric parameters are statistically independent random variables whose distribution laws are written for certain physical reasons.
 The combination of the known deterministic solution of the composite materials failure theory and probabilistic statistical methods that take into account the randomness of the material structure makes it possible to study the failure of composite materials taking into account the stochasticity of their structure.
 The main content of this article is the construction and analysis of the strength statistical characteristics algorithm of two-component lamellar composite materials. The mechanism of composite plate’s failure initiation in the inclusion is considered. The recorded relationships make it possible to calculate the most probable value, mean value, dispersion and coefficient of variation of strength and to investigate their dependence on the type of applied loading, structural heterogeneity of the composite and its dimensions (number of inclusions).
 The obtained results allow effective assessment of the reliability of stochastically defective two-component composite structural materials under complex stress conditions. This is due to the fact that the combined consideration of defectiveness and randomness in the composite material structure as interconnected, inseparable phenomena open new opportunities for researching of the strength problem and failure of composite materials under various types of applied loading.

Excitation and Reception of Higher-Order Guided Lamb Wave's A1 and S1 Modes in Plastic and Composite Materials.

Featured Application The developed new method will allow use for more detailed analysis and characterization of defects that cannot be detected with A0 or S0 modes. Contemporary technologies are employing composite plate materials developed by using various innovative materials (nanostructures, mica structures, etc.). Application of higher-order modes could allow better detection and characterization of defects characteristic of planar plastic and composite structures, mainly due to shorter wavelength. However, excitation of higher-order modes meets many problems, especially in the case of the air-coupled technique, and is not sufficiently investigated. This is relevant in the cases of paper, high-density polyethylene (HDPE), membranes, GFRP, GLARE, CFRP and other composite structures. The objective of the paper was investigation of the excitation and reception of higher-order guided Lamb wave modes in plastic and composite plates. Therefore, it is appropriate to develop new non-contact ultrasonic measurement methods based on the excitation and reception of guided waves for the study of such objects. The obtained results clearly demonstrate the possibility to excite and receive efficiently different higher-order guided Lamb wave modes with very different phase velocities. The presented comparison of the experimental results with the simulation results showed a good agreement. The combination of air-coupled excitation and non-contact reception enables a non-destructive evaluation and characterization of moving plastic objects and composite structures.