Effect Of Laminate Configuration Research Articles

Static and natural frequency investigation of FGP beams considering thermal effects and design parameters

This study presents a static analysis and natural frequency analysis of functionally graded laminated piezoelectric beams based on the Euler–Bernoulli theory using the finite element method. A simple power law is used to vary all material properties across the thickness, except for Poisson’s ratio. The effect of laminate configuration and volume fraction index on the deflection and natural frequency of beams made of functionally graded piezoelectric materials (FGPM) is investigated, and the relationship between deflection and different volume fraction indices under thermal, electrical, and mechanical loads is explored. The study shows that there is a certain volume fraction index that maximizes or minimizes deflection. Additionally, the variation of natural frequency in relation to the power law index is examined. The findings of this research are useful for the development of sensors and actuators in different environments, and the appropriate operation point of the structure can be selected based on the behavior of the sensor or actuator of the beam.

The effect of laminate configuration on the mechanical properties of model glued-laminated timber composed of single and mixed tropical fast-growing tree species

ABSTRACT The effects of laminate configuration on mechanical properties were investigated for model glued-laminated timber (GLT) composed of single and mixed fast-growing tree species (Acacia mangium Willd., Maesopsis eminii Engl., and Melia azedarach L.), which were grown in community forests in Indonesia. The simulation of lamina yield was decreased in graded GLT compared with that in GLT with randomly designed, while the mean values of simulated dynamic Young’s modulus (DMOE) in graded GLT were higher than those of GLT with randomly designed in each species. Graded GLT with mixed species should be produced to effectively utilize wood resources from fast-growing tree species. All mechanical properties showed higher values in single-species GLT especially for graded GLT, compared with solid lumber, suggesting that laminate configuration was effective for increasing mechanical properties. However, the factors that increase mechanical properties in single-species GLT differed among species. These factors can be evaluated by load-deflection curves. In GLT composed of single and mixed species produced with the same DMOE, almost all other mechanical properties were similar among laminate configurations. It is concluded that laminate configurations with different species and grades are useful for efficiently producing GLT with higher mechanical properties from multiple fast-growing tree species.

Lignocellulosic fiber reinforced composites: Progress, performance, properties, applications, and future perspectives

AbstractEnvironmental awareness across the world has motivated researchers to focus their attention on the use of cellulosic fiber as reinforcement in polymer matrices. Lignocellulosic fibers are an abundantly available resource in all countries, which is cheap and easily renewable. Also, due to their properties, cellulosic plant fibers exhibit a great potential for use in polymer reinforcement. As a result, considerable research and development efforts have been directed towards the use of cellulosic fibers as a reinforcing material in composites. The use of cellulosic fiber reinforced composites has continuously increased during recent years, which benefits the cultivation of fiber plants and the economy of the country. This research area continues to be of interest to both industry and academia, the use of cellulosic fibers in composite applications being investigated throughout the world. Cellulosic fiber reinforced composites are reasonably strong, lightweight, harmless to human health and the environment, and biodegradable, hence they have the potential to be used in various applications. Recent progress in cellulosic fiber composites research has illustrated their great potential as structural components in automobiles, aerospace structures, construction, and building, and so forth. This study is an effort to create awareness about the research works that have been published in the field of natural fiber composites. This review briefly illustrates the main paths and results of major research published in the field of natural fiber reinforced polymer composites. The topics covered include the aspects of fiber treatment to improve the mechanical properties of the composites, manufacturing methods, performance of hybrid composites, effect of laminate configuration, and many different applications of natural fiber composites. By presenting a systematic view of the work performed in this area so far, this review will hopefully serve as a starting point for the development of new ideas in the research on natural fiber polymer composites.

Effect of laminate configuration on the self-healing of hybrid laminates reinforced by unidirectional spread carbon fibers and woven carbon fibers

Effect of laminate configuration on the self-healing of hybrid laminates reinforced by unidirectional spread carbon fibers and woven carbon fibers

Damping optimization of symmetrically laminated plates with transverse shear deformation using lamination parameters

This paper deals with the damping characteristics of symmetrically laminated plates with transverse shear deformation. First, the effect of laminate configuration on the damping characteristics is investigated for cantilevered laminated plates based on the Reissner–Mindlin’s first-order shear deformation theory. To examine the effect of laminate configuration, the concept of specific damping capacity is introduced and the damping characteristics are represented on the lamination parameter plane, where the damped stiffness invariants in transverse shear are newly proposed in this paper. Next, the optimal laminate configurations for the cantilevered laminated plates with maximal damping are determined taking into account the transverse shear effect by using differential evolution in which lamination parameters are used as intermediate design variables. The relation between the laminate configurations and the damping characteristics is discussed based on the concept of lamination parameters.

Experimental characterization of damage behavior in polycyanate CFRP laminates under high temperature atmospheric exposure

This study focuses on the experimental characterization of damage behavior due to thermo-oxidative-induced matrix shrinkage in carbon fiber reinforced plastics (CFRP) with polycyanate ester. To investigate the effects of laminate configuration on matrix shrinkage behavior, [90]8 and [0]8 unidirectional laminates, [±45]2S angle ply laminates, and [45/0/–45/90]3S quasi-isotropic laminates were exposed to high temperature atmospheric environment at 180 °C to analyze matrix shrinkage up to 2000 h. These samples were removed from convection oven to observe sample side surface changes. The thermo-oxidative-induced matrix shrinkage was measured on the side surface of CFRP sample by confocal laser microscopy. The results suggested thermo-oxidative-induced matrix shrinkage depended on aged hours, fiber-to-fiber distance, and fiber orientation angle. The matrix shrinkage coefficient could be calculated with a tensorial transformation and empirical formula. The model can predict matrix shrinkage tendency of the 45° intra-lamina layer in quasi-isotropic laminate using the data of 0° and 90° matrix shrinkage in the quasi-isotropic laminates.

Prediction of through the width delamination growth in post-buckled laminates under fatigue loading using de-cohesive law

Initiation and growth of delamination is a great concern of designers of composite structures. Interface elements with de-cohesive constitutive law in the content of continuum damage mechanics can be used to predict initiation and growth of delamination in single and mixed mode conditions. In this paper, an interface element based on the cohesive zone method has been developed to simulate delaminatoin growth of post-buckled laminate under fatigue loading. The model was programmed as the user element and user material by the "User Programmable Features" in ANSYS finite element software. The interface element is a three-dimensional 20 node brick with small thickness. Because of mixed-mode condition of stress field at the delamination-front of post-buckled laminates, a mixed-mode bilinear constitutive law has been used as user material in this model. The constitutive law of interface element has been verified by modelling of a single element. A composite laminate with initial delamination under quasi-static compressive Loading available from literature has been remodeled with the present approach. Moreover, it will be shown that, the closer the delamination to the free surface of laminate, the slower the delamination growth under compressive fatigue loading. The effects of laminate configuration on delamination growth are also investigated.

Effect of laminate configuration and feed rate on cutting performance when drilling holes in carbon fibre reinforced plastic composites

Composites use in the aerospace industry is expanding, in particular carbon fibre reinforced plastics (CFRP) for structural components. Machinability can however be problematic especially when drilling, due to CFRP's inherent anisotropy/in-homogeneity, limited plastic deformation and abrasive characteristics. Following a brief review on composites development and associated machining, the paper outlines experimental results when twist drilling 1.5 mm diameter holes in 3 mm thick CFRP laminate using tungsten carbide (WC) stepped drills. The control variables considered were prepreg type (3 types) and form (unidirectional (UD) and woven), together with drill feed rate (0.2 and 0.4 mm/rev). A full factorial experimental design was used involving 12 tests. Response variables included the number of drilled holes (wear criterion VB Bmax ≤ 100 μm), thrust force and torque, together with entry and exit delamination (conventional and adjusted delamination factor values calculated) and hole diameter. Best results were obtained with woven MTM44-1/HTS oven cured material (3750 holes) while the effect of prepreg form on tool life was evident only when operating at the higher level of feed rate. Thrust forces were typically under 125 N with torque values generally below 65 Nmm over the range of operating parameters employed. Finally, the delamination factor ( F d ) measured at hole entry and exit ranged between ∼1.2–1.8 and 1.0–2.1 respectively.

Impact properties of glass/plant fibre hybrid laminates

The use of plants fibre reinforced composites has continuously increased during recent years. Their low density, higher environmental friendliness, and reduced cost proved particularly attractive for low-tech applications e.g., in building, automotive and leisure time industry. However, a major limitation to the use of these materials in structural components is unsatisfactory impact performance. An intermediate approach, the production of glass/plant fibre hybrid laminates, has also been explored, trying to obtain materials with sufficient impact properties, whilst retaining a reduced cost and a substantial environmental gain. A survey is given on some aspects, crucial for the use of glass/plant fibre hybrid laminates in structural components: performance of hybrids when subjected to impact testing; the effect of laminate configuration, manufacturing procedure and fibre treatment on impact properties of the composite. Finally, indications are provided for a suitable selection of plant fibres with minimal extraction damage and sufficient toughness, for introduction in an impact-resistant glass/plant fibre hybrid laminate.

Effect of laminate configuration on the modulus of elasticity of glulam evaluated using a strain gauge method

The purpose of this study was to measure the strain of glulam laminae by affixing a strain gauge at the central axis of the lateral face in order to determine the effect of the configuration of the glulam. Japanese cedar and southern pine were used in the study. The strain and stress of the laminae during the bending test were recorded, and the modulus of elasticity (MOE) was calculated. The influence of the MOE of the adhesive layers was also considered. Results showed that the MOE of the laminated elements increased as its specific gravity increased, although the specific gravity was not the only factor evaluated. The MOE of glulam (E bsg) measured by the strain gauge method was very close to the observed MOE of glulam (E b) and a significant linear relationship was identified. The MOE (e) of laminae measured by the strain gauge method was very close to that determined (E) under the “free condition” before bonding. The difference between the modified MOE (E bsa) and E bsg was not significant. The MOE of glulams made of heterogeneously graded lumbers were about 23% and 31% larger than the average MOE of their laminae for Japanese cedar and southern pine, respectively. The actual neutral axis was just below the longitudinal center line. It shifted slightly within the proportional limit range and moved downward when the load increased.

Effect of Laminate Configuration on the Properties of Glass Fiber-reinforced Plastics (GFRPs) Mixed Composites

Studies on the effect of laminate configuration on the properties of glass fiberreinforced plastics (GFRPs) are carried out. The GFRP-laminated composites are prepared by a hand lay-up technique. Five types of laminate configurations are prepared, and the correlation between different laminate configurations and the end physical and flexural properties are analyzed. In this present study, the effect of water absorption on the flexural properties of GFRP composites is examined. As a result, it is found that the properties of GFRPs are governed by the laminate configurations of the laminate system, which further influence the properties of GFRPs after the water absorption test.

Polymer-matrix composites subjected to low-velocity impact: effect of laminate configuration

Effect of laminate configuration on the impact behaviour of different polymer-matrix composites subjected to a transverse central low-velocity point impact load has been studied. For this a 3D transient finite-element analysis code using a modified Hertz law has been used. Quadratic failure criteria have been used to predict in-plane and interlaminar failure initiation. The studies have been carried out with plate dimensions of 150 mm×150 mm×6 mm with a simply supported boundary condition. For these studies, an incident impact velocity of 3 m/s and an impactor mass of 50 g have been used. Studies have been carried out on different mixed composites, cross-ply laminates, woven-fabric composites and 3D composites. It is observed that mixing of unidirectional and woven-fabric layers leads to the reduction of the failure function.

Effect of Laminate Configuration on the Damage Progress and Strain Concentration in CFRP Laminates with an Open Hole

Effect of Laminate Configuration on the Damage Progress and Strain Concentration in CFRP Laminates with an Open Hole

Effect of Laminate Configuration and Impactor's Mass on the Initial Impact Damage of Graphite/Epoxy Composite Plates Due to Line-Loading Impact

An investigation was performed to study the effect of stacking sequence, thickness, and impactor's mass on the impact damage of graphite/epoxy laminated com posites due to low-velocity impact. The major focus of the study was concentrated on the initial damage and the corresponding impact energy with respect to these parameters. Ex periments were performed using specially designed line-nose impactors by which the re sulting impact damage and failure mode of the composites could easily be inspected. Ac cordingly, the velocities of the impactors causing initial impact damage in the composites were determined, and the effects of the laminate configuration and the mass of the impac tor on the damage were established. Numerical simulations based on the model, which was developed previously, were also performed in order to understand the basic mechanics and mechanisms governing the phenomena observed from the experiments. Based on the study, it can be concluded that the change of stacking sequence significantly influences the impact damage much more than the change of thickness. Initial impact damage is also very sensitive to the mass of the impactor, and both velocity and mass of the impactor have to be specified in order to adequately characterize impact damage in composites.

The Effect of Laminate Configuration on Characteristic Lengths and Rail Shear Strength

Tests were performed measuring the characteristic lengths in tension and in com pression and the rail shear strength of Fiberite T300/1034-C graphite epoxy com posites. The results show the effects of geometry on the characteristic lengths. The results also indicate the variability of rail shear strength with the volume fraction of zero degree plies in the laminate.