Laminate Stacking Research Articles

Numerical Investigation of Multi-scale Characteristics of Single and Multi-layered Woven Structures

Resin flow through multi-ply woven fabrics is affected by the fibre orientation and laminate stacking sequence during the impregnation process. This is characterised by permeability, which measures the ability of transferring fluids within a 2D or 3D layered woven fibre architecture (i.e., through a porous medium). The work aims to investigate the feasibility of characterising macro-scale flow permeability via the micro-meso-scale (dual-scale) permeability across and along woven yarns, with different structures of yarn nesting, non-shifting, and ply orientation. The permeability characterisation is performed using Ansys-Fluent software package where textile architectures and resin flow in porous media are simulated. The results show that in- and out-plane permeability of the nested, non-shifted and oriented single-ply woven preforms are different than that corresponding to multi-layered plates, making them only applicable for dual-scale permeabilities. However, with a number of plies in the multi-ply woven fabrics — e.g., 9-ply and 5-ply, for in- and out-of-plane flows, respectively — the dual-scale permeabilities can be extended to macro-flow making them applicable at all scales (multi-scale flow). The calculated in-plane multi-scale permeabilities are then used in the 2D simulations and compared with the analytical solution of the Darcy’s equation, which resulted in a very good agreement.

Tuning Hyrbrid Ferroelectric and Antiferroelectric Stacks for Low Power FeFET and FeRAM Applications by Using Laminated HSO and HZO films

AbstractThe properties of hybrid ferroelectric (FE) and antiFE (AFE) films integrated in a single capacitor stack is reported. The stack lamination (4 × 5 nm) or (2 × 10 nm) using an Alumina (Al2O3) interlayer, material type (Si‐doped HfO2 (HSO) and Zr doped HfO2 (HZO)), precursor condition (TEMA‐Hf and Hf/ZrCl4), or dopant concentration (Si and Zr) are investigated for laminate stack properties. Optimized FE properties (higher 2Pr and a lower fraction of the monoclinic phase) are observed at (2 × 10 nm) laminates compared to a single 20 nm film thickness. The hybrid laminate stack as FE‐FE, AFE‐FE, DE‐FE, or DE‐AFE using (2 × 10 nm) based laminates are explored in terms of the output FE hysteresis (2Pr, 2Ec) and structural properties by X‐ray diffraction. The hybrid AFE‐FE stack shows the potential of tailoring the output FE hysteresis 2Ec by varying the fraction of the AFE phase. The hybrid AFE‐FE stack is studied for the HSO and HZO materials at optimal FE content for the first laminate layer while varying the Si or Zr content to stabilize different degrees of an AFE phase in the second laminate layer. The superposition of the hybrid AFE‐FE hysteresis shows a systematic 2Ec control. A model is developed to describe the tailored output FE hysteresis via the tuning of a hybrid AFE‐FE stack. The role of stack lamination at hybrid‐stabilized phases inside a single stack is explored with the aim for a controlled and optimized FE hysteresis shape toward a low power (2Ec) operation.

Effect of End-Winding on Electromagnetic Performance of Fractional Slot and Vernier PM Machines With Different Slot/Pole Number Combinations and Winding Configurations

In this paper, the effects of end-winding on electromagnetic performance of surface mounted permanent magnet machines (SPMMs) (including vernier machines) with different slot/pole number combinations and winding configurations are analyzed and compared. By using genetic algorithm based on finite element analysis, SPMMs with different coil pitches are optimized for maximum average torque under fixed copper loss or fixed copper and iron losses, with/without considering the influence of end-winding. The effects of coil pitch and stack length on torque and torque density are investigated, and the optimal coil pitch for each slot/pole number combination is obtained. The efficiencies, inductances, and power factors of optimized SPMMs are also compared. The torques of optimized SPMMs considering iron loss decrease, especially at high speed and larger rotor pole number. It is found that the end-winding has significant effect on torque, torque density, winding inductance, and power factor etc. Compared with the fractional slot concentrated winding SPMMs with the same lamination stack length but slot number higher than pole number, the integer-slot distributed winding SPMMs with pole number higher than slot number have higher torques due to field modulation effect, but lower torque densities due to longer axial end-winding lengths.

Effect of Manufacturing Influences on Magnetic Performance Parameters of Sub-Fractional Horsepower Motors

Depending on the stator lamination manufacturing processes (e.g., punching, laser cutting, clamping, welding, interlocking, and bonding), the motor’s magnetic performance parameters, such as cogging torque, hysteresis torque, and iron losses, can vary significantly. In sub-fractional horsepower (SFHP) permanent magnet motors, the manufacturing influence is typically even more severe because, due to their small dimensions, practically, the whole stator material is likely to be affected. This article analyzes the magnetic performance parameters cogging torque, hysteresis torque, and iron losses of three different stator lamination stacks (i.e., M250-35A punched with interlocking, M250-35A laser cut with bonding, and NO10 laser cut with bonding) of an SFHP single-phase brushless permanent magnet motor often found in automotive fan applications. A rheometer is used for extremely accurate torque measurements in the sub-millinewton meter range, and electron backscatter diffraction measurements are performed to visualize changes in the grain morphology and crystal orientation. The findings reveal that the punched stator with interlocking is affected the most by the manufacturing process, showing the lowest cogging torque yet the highest average hysteresis torque and thus up to 40% higher iron losses. The results presented in this article allow for both making basic stator lamination design choices and translating the iron losses, as well as the hysteresis torque and cogging torque waveforms, of a laser cut and bonded prototype into those of its punched and interlocked mass-produced counterpart.

Effect of Glass Fiber Hybridization on the Durability in Salt-Fog Environment of Pinned Flax Composites.

The aim of the present paper is to evaluate the effect of the hybridization with external layers of glass fibers on the durability of flax fiber reinforced composites in severe aging conditions. To this scope, full glass, full flax and hybrid glass–flax pinned laminates were exposed to a salt-fog environment for up to 60 days. Double-lap pinned joint tests were performed to assess the pin-hole joints performances at varying the laminate stacking sequence. In order to better discriminate the relationship between the mechanical behavior and the fracture mechanisms of joints at increasing the aging time, different geometries (i.e., by varying both the hole diameter D and the free edge distance from the center of the hole E) were investigated after 0 (i.e., unaged samples), 30 and 60 days of salt-fog exposition. It was shown that the hybridization positively affects the mechanical performance as well as the stability of pinned composites: i.e., improvements in both strength and durability against the salt-fog environment were evidenced. Indeed, the hybrid laminate exhibited a reduction in the bearing strength of about 20% after 60 days of aging, despite to full flax laminate, for which a total reduction in the bearing strength of 29% was observed. Finally, a simplified joint failure map was assessed, which clusters the main failure mechanisms observed for pinned composites at varying aging conditions, thus assisting the joining design of flax–glass hybrid laminates.

The Effect of Stacking Sequence on Fatigue Behaviour of Hybrid Pineapple Leaf Fibre/Carbon-Fibre-Reinforced Epoxy Composites.

This study examined the fatigue behaviour of pineapple leaf fibre/carbon hybrid laminate composites under various stacking sequences. The vacuum infusion technique was used to fabricate the symmetric quasi-isotropic oriented laminates, in which the stacking was varied. The laminate was tested under static and fatigue tensile load according to ASTM D3039-76 and ASTM D3479-96, respectively. Maximum tensile strength and modulus of 119.34 MPa and 6.86 GPa, respectively, were recorded for the laminate with external PALF ply and internal carbon ply oriented at [± 45°2, 0°/90°2]s (PCCP_45090). The fatigue tests showed that PCCP_45090 and CPPC_09045 (with internal PALF ply and external carbon ply oriented at [0°/90°2, ± 45°2]s) exhibited a higher useful life, especially at the high-stress level of the ultimate tensile strength. The normalised stress against the number of cycles showed that the stacking sequences of different ply orientations affected the fatigue behaviour more than the stacking sequences of the material. The laminate stacking sequence significantly affected the hysteresis energy and stiffness evolution. The scanning electron microscopy images showed that the fatigue failure modes included fibre pull-out, fibre breakage, matrix cracking, debonding, and delamination. The study concluded that PCCP_45090 exhibited an outstanding fatigue performance.

Enhanced Hyper-Cube Framework Ant Colony Optimization for Combinatorial Optimization Problems

Solving of combinatorial optimization problems is a common practice in real-life engineering applications. Trusses, cranes, and composite laminated structures are some good examples that fall under this category of optimization problems. Those examples have a common feature of discrete design domain that turn them into a set of NP-hard optimization problems. Determining the right optimization algorithm for such problems is a precious point that tends to impact the overall cost of the design process. Furthermore, reinforcing the performance of a prospective optimization algorithm reduces the design cost. In the current study, a comprehensive assessment criterion has been developed to assess the performance of meta-heuristic (MH) solutions in the domain of structural design. Thereafter, the proposed criterion was employed to compare five different variants of Ant Colony Optimization (ACO). It was done by using a well-known structural optimization problem of laminate Stacking Sequence Design (SSD). The initial results of the comparison study reveal that the Hyper-Cube Framework (HCF) ACO variant outperforms the others. Consequently, an investigation of further improvement led to introducing an enhanced version of HCFACO (or EHCFACO). Eventually, the performance assessment of the EHCFACO variant showed that the average practical reliability became more than twice that of the standard ACO, and the normalized price decreased more to hold at 28.92 instead of 51.17.

Modal Characterization of Sandwich Skew Plates

Abstract The current work focuses on the experimental and finite element free vibration studies of laminated composite sandwich skew plates. The comparison was made between the experimental values obtained by the Fast Fourier transform (FFT) analyzer and a finite element solution obtained from CQUAD8 finite element of The MacNeal-Schwendler Corporation (MSC) / NASA STRucture Analysis (NASTRAN) software. The influence of parameters such as aspect ratio (AR) (a/b), skew angle (α), edge condition, laminate stacking sequence, and fiber orientation angle (θ°) on the natural frequencies of sandwich skew plates was studied. The values obtained by both the finite element and experiment approaches are in good agreement. The natural frequencies increase with an increase in the skew angle for all given ARs.

Concurrent topology and stacking sequence optimization of composite laminate plates using lamination parameters

Design engineers are constantly striving to minimize part weight, maximize stiffness, reduce cost, and optimize material usage. In this context, the use of composite materials provides an advantage when developing light-weight components because of their high strength to weight ratio and optimization potential. Most traditional topology optimization methods have been developed for isotropic materials and adapted to consider direction-dependent materials only to define the optimum shape based on the fixed properties. Nevertheless, due to its anisotropic nature, a unidirectional composite mechanical response is highly dependent on the laminate stacking sequence, which is typically specified after the shape of the components has been defined. Therefore, new methods that can concurrently account for the shape and laminate orientation are essential for designing optimum composite structures. This article proposes a new density-based methodology for performing simultaneous topology optimization and stacking sequence optimization of constant stiffness laminated plates. In order to effectively achieve simultaneous placement of material and laminate lay-up, lamination parameters are used as design variables. Feasible domain equations are defined for lamination parameters and a laminate database concept is used for retrieving the lamination angles. Multiple example problems are provided to demonstrate the applicability of the proposed approach.

Buckling optimization of composite rectangular plates by sequential permutation search with bending-twisting correction

Buckling problem of composite plates is of importance since it is commonly encountered in thin-walled structural components in engineering. Buckling resistance design of composite plates involves the design of laminate stacking sequence exhibiting high dimensional discrete variables owing to the combination and permutation of ply orientations of layers. In this work, a sequential permutation search (SPS) optimization algorithm is presented for the stacking sequence design of composite rectangular plates accounting for the inherent physical-mechanical behavior of composite laminates. Owing to that the governing equation for buckling of composite rectangular plates is a linear homogeneous equation on bending stiffness parameters, the convexity of flexural lamination parameters and sensitivity of bending stiffness are utilized to construct sensitive detection techniques and linear search procedures. Moreover, to increase the robustness of SPS, a sign optimization algorithm (SOA) is coupled in SPS to regulate bending-twisting coupling effects. The SPS algorithm is applied to the buckling resistance design of composite rectangular plates exhibiting various boundaries under axial compression, where the Rayleigh-Ritz method is developed to perform the buckling analysis. Optimal results of SPS are compared against layerwise optimization approach (LOA) and genetic algorithm (GA), illustrating its reliability and efficiency.

Mechanical Properties of Abaca-Glass Fiber Composites Fabricated by Vacuum-Assisted Resin Transfer Method.

The application of natural fiber-reinforced composites is gaining interest in the automotive, aerospace, construction, and marine fields due to its advantages of being environmentally friendly and lightweight, having a low cost, and having a lower energy consumption during production. The incorporation of natural fibers with glass fiber hybrid composites may lead to some engineering and industrial applications. In this study, abaca/glass fiber composites were prepared using the vacuum-assisted resin transfer method (VARTM). The effect of different lamination stacking sequences of abaca–glass fibers on the tensile, flexural, and impact properties was evaluated. The morphological failure behavior of the fractured-tensile property was evaluated by 3D X-ray Computed Tomography and Scanning Electron Microscopy (SEM). The results of mechanical properties were mainly dependent on the volume fraction of abaca fibers, glass fibers, and the arrangement of stacking sequences in the laminates. The higher volume fraction of abaca fiber resulted in a decrease in mechanical properties causing fiber fracture, resin cracking, and fiber pullout due to poor bonding between the fibers and the matrix. The addition of glass woven roving in the composites increased the mechanical properties despite the occurrence of severe delamination between the abaca–strand mat glass fiber.

The influence of multidirectional leakage flux on transformer core losses

In a power transformer, the leakage flux enters the laminations of the iron core in different directions. Depending on the orientation of the leakage flux, it can add eddy current and hysteresis losses to the well-documented losses caused by the main flux. To study the principles of the influence of the leakage flux on the losses in transformer cores, the problem was isolated to an experiment on a stack of laminations in an Epstein-like frame. The frame carried the main flux, while artificial leakage flux is created and forced to enter the laminations in the two directions perpendicular to the main flux. Additionally, the system was modelled using finite elements to interpret the physical phenomena. The results revealed that the loading conditions have a significant impact on the local eddy current loss and on the overall power loss. The identified additional magnetic losses show that under inductive loading, conventional no-load tests can underestimate the core losses considerably.

Stress and Failure Analysis of Composite Prosthetic Leg

Prosthesis is an artificial substitute for body parts such as limbs, eye, tooth, etc. Generally, the prosthesis is referred to as a fabricated substitute used to assist the damaged part of the body. The devices are made up of light materials like plastics, aluminium, and composites materials. The prosthetic technology is aimed to replicate the body part which is damaged irreversibly due to unfortunate incidents. The present work deals with creation of an optimized design for the prosthetic leg proposed by Saito et al. [2]. The material of prosthetic leg proposed here is made up of Carbon Fiber Reinforced Polymer (CFRP) composite laminate, having unidirectional and cross-ply stacking sequence, which is analyzed for static stress and failure loads. From the results, it is evident that, while a uni-directional laminate can withstand a failure load of 4910 N, a cross-ply laminate withstands 4282 N. Also, the individual ply versus stress is studied in this work.

Three-Axis Inductive Displacement Sensor Using Phase-Sensitive Digital Signal Processing for Industrial Magnetic Bearing Applications

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding.

Investigation of dynamic buckling of fiber metal laminate thin-walled columns under axial compression

This paper presents an investigation of the dynamic buckling phenomenon in thin-walled Fiber Metal Laminate short columns subjected to axial compressive loading. The numerical analysis is performed with the FEM ANSYS software for three profiles differentiate in the laminate stacking sequence. Two groups of criteria were implemented to assess the structure resistance to dynamic pulse loading: the dynamic buckling criteria and strength failure criteria. Parametric analysis was performed to determine the effect of initial geometric imperfection, laminate stacking sequence, and the pulse load's shape on the dynamic stability. The value of the amplitude of initial geometric imperfection and the shape of pulse load influence the value of critical Dynamic Load Factor strongly. Aluminium yielding was observed as the primary failure source developed in the FML structure subjected to the pulse loading.

Analysis of Bi-stable Hexagonal Composite Laminate Under Thermal Load

This paper concerns the non-linear morphing behavior of composite laminate for creating asymmetric bi-stability in the symmetric geometry. The hexagonal and compound trapezoidal-hexagonal geometry are the proposed solution to create asymmetric bi-stability as new geometries. By creating asymmetric bi-stability, the strain energy of the two stable states will be different. This difference prevents continuous actuating between stable states and helps to obtain effectively control in the morphing process. The effects of laminate stacking sequence, temperature, and geometry on the strain energy and out of plane displacements of the two stable states are investigated. The non-linear finite element method is used for simulation, and the numerical results are validated with the experiments. Using hexagonal geometry allows the creation of tessellated surfaces consisting of the bi-stable and mono-stable sections that can be deformed in different directions and can be used in the adaptive structures such as reflector antenna or control surfaces.

Buckling and vibration analysis of shape memory laminated composite beams under axially heterogeneous in-plane loads in the glass transition temperature region

Buckling and vibration study of the shape memory polymer composites (SMPC) across the glass transition temperature under heterogeneous loading conditions are presented. Finite element analysis based on C° continuity equation through the higher order shear deformation theory (HSDT) is employed considering non linear Von Karman approach to estimate critical buckling and vibration for the temperature span from 273 to 373 K. Extensive numerical investigations are presented to understand the effect of temperature, boundary conditions, aspect ratio, fiber orientations, laminate stacking and modes of phenomenon on the buckling and vibration behavior of SMPC beam along with the validation and convergence study. Effect of thermal conditions, particularly in the glass transition region of the shape memory polymer, is considerable and presents cohesive relation between dynamic modulus properties with magnitude of critical buckling and vibration. Moreover, it has also been inferred that type of axial loading condition along with the corresponding boundary conditions significantly affect the buckling and vibration load across the glass transition region.

Effect of stacking sequence on thermal stresses in laminated plates with a quasi-square cutout using the complex variable method

In this research, the influence of the laminate stacking sequence on thermal stress distribution in symmetric composite plates with a quasi-square cutout subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii's method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular cutout is extended to the quasi-square cutout. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, the aspect ratio of cutout, the flux angle and the composite material are examined on the thermal stress distribution. It is found out that the circular shape for cutout may not necessarily be the optimum geometry for all stacking sequences. The finite element analysis results are used to validate the analytical solution.

Identifying equivalent transversely isotropic material parameters for full‐surface bonded sheet‐layered lamination stacks

AbstractThe accurate prediction of the structural properties of sheet‐layered lamination stacks in rotors and stators of electric motors is a challenging task due to the special layer design. The joining technology has a major influence on the individual sheet interactions and on the macroscopic quantities. Here, full‐surface bonded lamination stacks are considered for which equivalent linear transversely isotropic material parameters are determined by modeling the bonding varnish using Zero‐Thickness interface elements. It is shown that this procedure delivers comparable results to those obtained with traditional methods, like the rule of mixture or by modeling the adhesive layer with 3D continuum elements.

Anisotropic Thermal Conductivity of Lamination Stacks of Non-oriented Electrical Steel

Anisotropic Thermal Conductivity of Lamination Stacks of Non-oriented Electrical Steel