Layer Orientation Angle Research Articles

High-efficient heat flux manipulation of micro-scale thermal metamaterials with facile functional unit design

Based on the novel macro-thermophysical properties exhibited by its peculiarly artificially design structure, thermal metamaterials have been widely used in the harvest and management of thermal energy. Herein, a facile micro-scale thermal functional unit structure is proposed assisted by an advanced picosecond laser technology to realize the fabrication of thermal metamaterials with thermal shielding and thermal concentrating. To obtain the optimal design criterion of thermal functional units, the effects of thermal conductivity ratio, layer orientation angle, and laminated thickness on thermal conduction are investigated. Both simulation and experiment validate that thermal metamaterials assembled by diverse thermal functional units with different orientation angles exhibit completely neoteric performances of thermal concentrating and shielding. Besides, the results verify that the micro-scale thermal metamaterials exhibit better heat flux regulation capability and higher thermal concentration efficiency. Additionally, the effect of inevitable air convection on the thermal performance of these metamaterials has also been evaluated. This work provides an effective strategy to achieve small-scale thermal energy harvesting and protection by using thermal metamaterials with micro-structure.

The effect of layer orientation angle and its increasing on mechanical properties of laminated material: A numerical study

The mechanical properties of a laminated material due to different layer orientation angle and pattern of layers are simulated using the finite element method. The aim of this paper is to determine the effect of the different layer orientation angles and patterns on the mechanical properties of laminated material. Stainless steel laminated with epoxy carbon is used in this study. The model is a rectangle plate with 150 mm in length, 80 mm in width, and 4 mm in thickness. Linear static finite element analyses with 0,63 MPa normal force is applied to the three various models with different layer orientation angles and patterns. The results show that different layer orientation angles and numbers affect the mechanical properties of the material.

A Study on Design of Frame Tube Bike Composite for Reducing Stress and Deformation Based on CEN 14766 Standards Test Methodology

In the previous study, frame tube design analysis is developed to provide a significant reduction in stress and deformation. This study aims to analyze the frame tube composite design. The design analysis by using FEM software is used to model frame tubes with shell elements. The layer angle orientation is set as design parameters. Material is carbon fiber composite (epoxy E-glass UD). Dimension thickness is 2 mm. Seat tube angle 74.5oand head tube angle 70.5o. Load is applied in static condition with weight loading on 80 Kg. Based on the simulation results, thesmallest deformation and stress values occur in the model with a layer orientation angle of [45o, 90o, 90o, 45o] with a deformation value of 0.099556 mm and a stress of 10.016 MPa.

Hygrothermal stress analysis of laminated composite porous plates

This paper presents the stress analysis of a composite laminated simply supported plate with porosity under hygrothermal rising. In the displacement-strain relation of the plate structure, the first shear plate deformation theory is used. Material properties of laminas are considered as orthotropic. Three different porosity distributions are used. In the solution process, the Navier method is implemented for simply supported laminated composite plate. Non-uniform temperature and moisture rising are considered for laminated plate with three laminas. In the numerical results, the stress distributions of the laminated plate are presented and discussed for different values of moisture, temperature, stacking sequence of laminas and orientation angle of layers. The numerical results show that the hygrothermal condition is very effective in the stress behavior of laminated plates.

Numerical Analysis of Composite Beams under Impact by a Rigid Particle

Analysis of a laminated composite beam under impact by a rigid particle is investigated. The importance of this project is to simulate the impact of objects on small scale aerial structures. The stresses are considered uni- axial bending with no torsion loading. The first order shear deformation theory is used to simulate the beam. After obtaining kinematic and potential energy for a laminated composite beam, the motion equations, boundary conditions and initial conditions are obtained by using Hamilton’s principle. The deformation of beam is considered large so these equations are nonlinear. Then by using the numerical methods such as generalize differential quadrature (GDQ) and Newmark methods, the equations will be converted in to a set of nonlinear algebraic equations. These nonlinear equations are solved by numerical methods such as Newton- Raphson. By solving the equations, the displacement of beam and rotation of cross section in terms of time for different number of points of beam for variety of orientation angle of layers are obtained. Then the displacements of impacted point of beam, stresses and contact forces in different times for variety of orientation of layers for different situations of impact are compared.

Modal Analysis and Investigation of Torsion Bar Strength based on Layer Orientation Angle using Composite Material

Modal Analysis and Investigation of Torsion Bar Strength based on Layer Orientation Angle using Composite Material

The Gravitational Search Algorithm in Antiresonance Layer Optimization of Laminated Composite Plates

In the present study, Gravitational Search Algorithm (GSA) is combined with Finite Element Method (FEM) for optimizing laminated composites vibration behavior. The fiber orientation angle of layers is considered as design variable. The 8-layerd and 12-layerd plates with both of square and rectangular shapes are investigated. Twenty distinct boundary conditions and [Formula: see text] of fiber angle increment are considered. The results of the proposed method are in good agreement with reference methods, and in some cases the GSA-FEM is more efficient. Moreover, the simple structure of GSA and its exploration and exploitation features avoids trapping in a local optimum.

Buckling analysis of embedded laminated plates with agglomerated CNT-reinforced composite layers using FSDT and DQM

Laminated plates have many applications in different industrials. Buckling analysis of these structures with the nano-scale reinforcement has not investigated yet. However, buckling analysis of embedded laminated plates with nanocomposite layers is studied in this paper. Considering the single-walled carbon nanotubes (SWCNTs) as reinforcement of layers, SWCNTs agglomeration effects and nonlinear analysis using numerical method are the main contributions of this paper. Mori-Tanaka model is applied for obtaining the equivalent material properties of structure and considering agglomeration effects. The elastic medium is simulated by spring and shear constants. Based on first order shear deformation theory (FSDT), the governing equations are derived based on energy method and Hamilton's principle. Differential quadrature method (DQM) is used for calculating the buckling load of system. The effects of different parameters such as the volume percent of SWCNTs, SWCNTs agglomeration, number of layers, orientation angle of layers, elastic medium, boundary conditions and axial mode number of plate on the buckling of the structure are shown. Results indicate that increasing volume percent of SWCNTs increases the buckling load of the plate. Furthermore, considering agglomeration effects decreases the buckling load of system. In addition, it is found that the present results have good agreement with other works.

Analytical solution for buckling of embedded laminated plates based on higher order shear deformation plate theory

In this research, buckling analysis of an embedded laminated composite plate is investigated. The elastic medium is simulated with spring constant of Winkler medium and shear layer. With considering higher order shear deformation theory (Reddy), the total potential energy of structure is calculated. Using Principle of Virtual Work, the constitutive equations are obtained. The analytical solution is performed in order to obtain the buckling loads. A detailed parametric study is conducted to elucidate the influences of the layer numbers, orientation angle of layers, geometrical parameters, elastic medium and type of load on the buckling load of the system. Results depict that the highest buckling load is related to the structure with angle-ply orientation type and with increasing the angle up to 45 degrees, the buckling load increases.

Electromagnetic interference shielding properties of carbon fiber cloth based composites with different layer orientation

Carbon fiber cloth/epoxy resin composites with different layer orientation angles were prepared to evaluate electromagnetic shielding properties in the X band. The results showed that the electrical conductivity, dielectric constant and shielding effectiveness of composites decreased with increase in layer angle. Absorbed power had the maximum value (0.577) at 49.60° with sample thickness 4.00mm. After using carbonyl iron powder as the radio wave absorber, both conductivity and shielding effectiveness improved when layer angle was beyond 10.06°. Reflected power decreased while absorbed power increased with increase in layer angle and their variation rates decreased. Structure and function integrated shielding products made of these composites can be used to get the highest shielding effectiveness or highest absorbed power with designed layer angles.

Expansion of plastic zone and residual stresses in the thermoplastic-matrix laminated plates ([0°/ θ°] 2) with a rectangular hole subjected to transverse uniformly distributed load expansion

The present paper focused on the understanding of elastic stress, residual stress and plastic zone growth in layers of stainless steel woven fiber-reinforced thermoplastic matrix composite laminated plates with rectangular hole by using the finite element method (FEM) and first-order shear deformation theory for small deformations. Moreover, the computer program was developed for small elasto-plastic stress analysis of laminated plates. The laminated plate with rectangular hole consists of four reinforced layers bonded symmetrically and antisymmetrically in [0°/ θ°] 2 configuration. Various applied distributed loads with different layer orientation angles and rectangular hole dimensions were used for obtaining corresponding variation of residual stresses and the expansions of the plastic regions. It was observed that the intensity of the stress components and plastic zones were the maximum near corners of the rectangular hole.

Physical interpretation of parameters in synergistic continuum damage mechanics model for laminates

The continuum damage mechanics (CDM) model by Talreja [Talreja R. Damage characterization by internal variables. In: Pipes RB, Talreja R, editors. Comput Mater Series, vol. 9. Dam Mech Comp Mater, Elsevier, Amsterdam; 1994, p. 53–78], which is one of the most efficient for damaged laminate stiffness determination, is analyzed using earlier developed theoretical framework which links the macro-response of a damaged laminate to the opening and sliding displacements of crack surfaces in an exact form. The physical meaning of the material parameters in CDM is revealed. Exact expressions for these parameters are derived and transformation rules with changing layer orientation angle presented. These parameters were previously considered as the most troublesome part of the CDM model with need for additional tests for their determination. The error introduced by the two main assumptions in the CDM model ((a) stiffness change is linear with respect to damage tensor, (b) crack face sliding effect can be neglected) is evaluated and found that the linearization is often justified but sliding cannot be neglected in most of the lay-ups.

Elasto-Plastic Stress Analysis of Thermoplastic Matrix Composite Laminated and Perforated Plates under In-Plane Loading

The study presents an elasto-plastic stress analysis in symmetric and antisymmetric cross-ply reinforced thermoplastic matrix composite laminated plates. The thermoplastic matrix composite layer reinforced by long stainless steel fiber is manufactured by using moulds under the action of 2 MPa pressure and heating up to 200°C. A laminated and perforated plate consists of four thermoplastic matrix layers is reinforced cross-ply and bonded symmetrically or antisymmetrically. The first-order shear deformation theory and nine node Lagrangian finite element are used. The residual stresses and the expansions of plastic regions are illustrated for various cases. The in-plane load and the layer orientation angle are increased gradually.

Layerwise adaptive topology optimization of laminate structures

Presents a simple heuristic optimization algorithm to determine weight‐minimal laminate structures. The algorithm is based on an inverted form of growth strategy, where material is removed in areas with low stresses. In the presented algorithm the removal of material is performed in a layerwise manner in areas with low stress or in areas where the layer orientation angle differs significantly from the principal stress direction. In order to get a production‐adapted structure, the layer orientation angles of the available individual plies are not modified and the material is removed only locally in the respective plies. Contrary to a more formal mathematical optimization no sensitivity analyses are needed by the procedure outlined so far and this keeps the corresponding numerical effort reasonably low. The structural analyses have been performed by the Finite Element Program ANSYS and the outlined heuristic algorithm has been implemented by ANSYS‐macros. Several examples of rectangular laminate plates show the effectiveness of the present algorithm.

The use of an energy-based criterion to determine optimum configurations of fibrous composites

The strength optimization of laminated composites under in-plane loading is considered. An effective application of a numerical optimization method has been demonstrated for the optimum laminate configuration to maximize the in-plane strength of laminated fibrous composites. Two composite materials are considered in this study; boron/epoxy and carbon/epoxy. An energy-based failure criterion is used as a first-ply-failure strength criterion. The optimization algorithm is based on the sequential linear programming method with small step limits with respect to the layer thickness. Layer thicknesses and orientations are chosen as the design variables and the total thickness of the laminate is selected as the objective function. Owing to the significance of the problem, the present paper also shows the interaction among various variables such as layer thickness, layer orientation angle, in-plane loading, stresses and energy components.

Dynamic analysis and damping of composite structures embedded with viscoelastic layers

Abstract In recent years, it has been found that composites co-cured with viscoelastic materials can enhance the damping capacity of a composite structural system with little reduction in stiffness and strength. Because of the anisotropy of the constraining layers, the damping mechanism of co-cured composites is quite different from that of conventional structures with metal constraining layers. This paper presents an analysis of the dynamic properties of multiple damping layer, laminated composite beams with anisotropic stiffness layers, by means of the finite element-based modal strain energy method. ANSYS 4.4A finite element software has been used for this study. The variation of resonance frequencies and modal loss factors of various beam samples with temperature is studied. Some of these results are compared with the closed-form theoretical results of an earlier published work. For obtaining optimium dynamic properties, the effects of different parameters, such as layer orientation angle and compliant layering, are studied. Also, the effect of using a combination of different damping materials in the system for obtaining stable damping properties over a wide temperature range is studied.

Efficient Strength Optimization Approach on Composite Structures Based on Approximation Method.

We present an efficient strength optimization approach on laminated composite structures under in-plane loading where layer orientation angles in addition to layer thicknesses are used as design variables. A high-quality approximation of stress components is generated by a linear approximation of stress resultants with respect to intermediate design variables. An approximation method is then applied to a minimum-weight design of laminated panels under strength constraints. The validity of the present approach is verified through several optimization examples of laminated panels.

Strength optimization of laminated composites with respect to layer thickness and/or layer orientation angle

This paper deals with the strength optimization problem of laminated composites under in-plane loading based upon the mathematical programming method. Design variables are the layer orientation angles as well as the layer thicknesses. New treatment of design variables with respect to the layer orientation angles is presented. A technique is also proposed to delete the strength constraints of almost zero thickness layers. This new treatment gives an efficient optimization approach of laminated composites.

Minimum Weight Design of Laminated Composite Panels under Strength and Displacement Constraints

The present paper treats a minimum weight design of laminated composite panels under in-plane loading. Constraints consist of strength and displacement conditions. Layer orientation angles as well as layer thicknesses are used as design variables. An approximation method is applied to generate a high-quality approximate optimization problem. Stress components are evaluated using a linear approximation of stress resultants while displacements are approximated in a linear form. Transformed design variables with respect to the layer angles are also introduced to reduce the nonlinearity between the strength constraints and the layer angles. It is shown that optimal laminate configurations can be obtained with fewer than ten iterations.

単一の面内荷重を受ける積層材の強度制約下の最小重量設計

The present paper shows a reliable and efficient optimization approach on a minimum weight design of laminated composites under a single in-plane loading. Layer orientation angles as well as layer thicknesses are used as design variables, and the optimization technique is based upon a mathematical programming method. Transformed design variables with respect to the layer orientation angles in the principal loading direction are introduced to reduce the nonlinearity between strength constraints and design variables. A technique is also proposed to delete the strength constraints of almost zero thickness layers.