scholarly journals Buckling Optimization of Variable Stiffness Composite Panels for Curvilinear Fibers and Grid Stiffeners

2021 ◽  
Vol 5 (12) ◽  
pp. 324
Author(s):  
Sofía Arranz ◽  
Abdolrasoul Sohouli ◽  
Afzal Suleman
Keyword(s):  
Boundary Conditions ◽  
Fiber Orientation ◽  
Fiber Composite ◽  
Variable Stiffness ◽  
Buckling Load ◽  
Composite Panels ◽  
Spatial Direction ◽  
Percentage Difference ◽  
Stiffener Layout ◽  
Curvilinear Fibers

Automated Fiber Placement (AFP) machines can manufacture composite panels with curvilinear fibers. In this article, the critical buckling load of grid-stiffened curvilinear fiber composite panels is maximized using a genetic algorithm. The skin is composed of layers in which the fiber orientation varies along one spatial direction. The design variables are the fiber orientation of the panel for each layer and the stiffener layout. Manufacturing constraints in terms of maximum curvature allowable by the AFP machine are imposed for both skin and stiffener fibers. The effect of manufacturing-induced gaps in the laminates is also incorporated. The finite element method is used to perform the buckling analyses. The panels are subjected to in-plane compressive and shear loads under several boundary conditions. Optimization results show that the percentage difference in the buckling load between curvilinear and straight fiber panels depends on the load case and boundary conditions.

Size-dependent behavior of laminates with curvilinear fibers made by automated fiber placement

2015 ◽  
Vol 22 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Mahdi Arian Nik ◽  
Larry Lessard ◽  
Damiano Pasini
Keyword(s):  
Variable Stiffness ◽  
Buckling Load ◽  
Fiber Placement ◽  
Plate Size ◽  
Load Increase ◽  
Automated Fiber Placement ◽  
Fiber Path ◽  
Turning Radius ◽  
Curvilinear Fibers ◽  
Minimum Turning Radius

AbstractVariable stiffness laminates can be manufactured using curvilinear fiber paths. A curvilinear fiber path is generally defined based on the plate size and has a curvature that is dependent on the plate size. In practice, however, the fiber path must satisfy manufacturing constraints, such as the minimum turning radius imposed by the automated fiber placement machine, thereby limiting the possible amount of fiber steering. In this work, we studied the effect of the plate size on the structural properties of a plate manufactured with curvilinear fibers. We considered four plate sizes, which were designed by a constant curvature fiber path. We optimized the plates for both maximum buckling load and in-plane stiffness. The results showed that the in-plane stiffness of the plate was not controlled by the plate size, whereas the buckling load was highly affected by the curvature of the fiber path. Hence, the potential of a buckling load increase reduced for plate sizes smaller than the minimum turning radius. In addition, for a given maximum curvature of the fiber path, the influence of a complex layup on the buckling load was marginal.

scholarly journals Thermal Buckling Behaviour of Thin and Thick Variable-Stiffness Panels

2018 ◽  
Vol 2 (4) ◽  
pp. 58 ◽  
Author(s):  
Riccardo Vescovini ◽  
Lorenzo Dozio
Keyword(s):  
Boundary Conditions ◽  
Variable Stiffness ◽  
Thermal Buckling ◽  
Thin Plates ◽  
Composite Panels ◽  
Computationally Efficient ◽  
Stiffness Properties ◽  
Stiffness Design ◽  
Kinematic Approach ◽  
Insight Into

The possibility of designing composite panels with non-uniform stiffness properties offers a chance for achieving highly-efficient configurations. This is particularly true for buckling-prone structures, whose response can be shaped through a proper distribution of the membrane and bending stiffnesses. The thermal buckling behaviour of composite panels is among the aspects that could largely benefit from the adoption of a variable-stiffness design, but, in spite of that, it has rarely been addressed. The paper illustrates a semi-analytical approach for evaluating the thermal buckling response of variable-stiffness plates (VSP) by considering different boundary conditions. The formulation relies upon the method of Ritz and a variable-kinematic approach, leading to a computationally efficient implementation, which is particularly useful for exploring the larger design spaces, typical of variable-stiffness configurations. Due to the possibility of choosing the underlying kinematic approach as an input of the analysis, the formulation is not restricted to thin plates, but is suitable for analyzing the response of thick plates as well. Novel results are derived, which can be useful for benchmarking purposes and for gathering insight into the mechanical behaviour of variable-stiffness plates. Furthermore, the importance of transverse shear flexibility is illustrated with respect to the boundary conditions as well as the degree of steering of the fibers.

Design of variable-stiffness composite panels for maximum buckling load

2009 ◽  
Vol 87 (1) ◽  
pp. 109-117 ◽  
Author(s):  
Shahriar Setoodeh ◽  
Mostafa M. Abdalla ◽  
Samuel T. IJsselmuiden ◽  
Zafer Gürdal
Keyword(s):  
Variable Stiffness ◽  
Buckling Load ◽  
Composite Panels

Design of Variable Stiffness Cylinder with Holes Under Bending for Maximum Buckling Load Using Lamination Parameters

2019 ◽  
Author(s):  
Mazen Albazzan ◽  
Brian Tatting ◽  
Ramy Harik ◽  
Zafer Gürdal ◽  
Adriana Blom-Schieber ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Buckling Load ◽  
Lamination Parameters

scholarly journals Characterization and ballistic performance of thin pre-damaged resin-starved aramid-fiber composite panels

2021 ◽  
pp. 004051752110134
Author(s):  
Cerise A Edwards ◽  
Stephen L Ogin ◽  
David A Jesson ◽  
Matthew Oldfield ◽  
Rebecca L Livesey ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Plane Deformation ◽  
Ballistic Impact ◽  
Image Correlation ◽  
Composite Panel ◽  
Composite Panels ◽  
Micro Computed Tomography ◽  
Ballistic Performance ◽  
Low Level ◽  
Out Of Plane

Military personnel use protective armor systems that are frequently exposed to low-level damage, such as non-ballistic impact, wear-and-tear from everyday use, and damage during storage of equipment. The extent to which such low-level pre-damage could affect the performance of an armor system is unknown. In this work, low-level pre-damage has been introduced into a Kevlar/phenolic resin-starved composite panel using tensile loading. The tensile stress–strain behavior of this eight-layer material has been investigated and has been found to have two distinct regions; these have been understood in terms of the microstructure and damage within the composite panels investigated using micro-computed tomography and digital image correlation. Ballistic testing carried out on pristine (control) and pre-damaged panels did not indicate any difference in the V50 ballistic performance. However, an indication of a difference in response to ballistic impact was observed; the area of maximal local out-of-plane deformation for the pre-damaged panels was found to be twice that of the control panels, and the global out-of-plane deformation across the panel was also larger.

Optimization of Vibration Reduction in a Helicopter Blade With 2 Way Fluid-Structure Interaction

2018 ◽  
Author(s):  
Mürüvvet Sinem Sicim ◽  
Metin Orhan Kaya
Keyword(s):  
Cantilever Beam ◽  
Fiber Orientation ◽  
Structural Model ◽  
Fiber Composite ◽  
Vibration Reduction ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Helicopter Blade ◽  
Structure Interaction ◽  
Blade Model

The main goal of this study is the optimization of vibration reduction on helicopter blade by using macro fiber composite (MFC) actuator under pressure loading. Due to unsteady aerodynamic conditions, vibration occurs mainly on the rotor blade during forward flight and hover. High level of vibration effects fatigue life of components, flight envelope, pleasant for passengers and crew. In this study, the vibration reduction phenomenon on helicopter blade is investigated. 3D helicopter blade model is used to perform the aeroelastic behavior of a helicopter blade. Blade design is created by Spaceclaim and finite element analysis is conducted by ANSYS 19.0. Generated model are solved via Fluent by using two-way fluid-solid coupling analysis, then the analyzed results (all aerodynamic loads) are directly transferred to the structural model. Mechanical results (displacement etc.) are also handed over to the Fluent analysis by helping fluid-structure interaction interface. Modal and harmonic analysis are performed after FSI analysis. Shark 120 unmanned helicopter blade model is used with NACA 23012 airfoil. The baseline of the blade structure consists of D spar made of unidirectional Glass Fiber Reinforced Polymer +45°/−45° GFRP skin. MFC, which was developed by NASA’s Langley Research Center for the shaping of aerospace structures, is applied on both upper and lower surfaces of the blade to reduce the amplitude in the twist mode resonant frequency. D33 effect is important for elongation and to observe twist motion. To foresee the behavior of the MFC, thermo-elasticity analogy approach is applied to the model. Therefore, piezoelectric voltage actuation is applied as a temperature change on ANSYS. The thermal analogy is validated by using static behavior of cantilever beam with distributed induced strain actuators. Results for cantilever beam are compared to experimental results and ADINA code results existing in the literature. The effects of fiber orientation of MFC actuator and applied voltage on vibration reduction on helicopter blade are represented. The study shows that torsion mode determines the optimum placement of actuators. Fiber orientation of the MFC has few and limited influences on results. Additionally, the voltage applied on MFC has strong effects on the results and they must be selected according to applied model.

scholarly journals Optimization of Laminated Composite Plates for Maximum Biaxial Buckling Load

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Buckling Load ◽  
Biaxial Compression ◽  
Laminated Composite Plates ◽  
Design Variables ◽  
Fiber Orientation Angle

This paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.

Effect of Fiber Orientation on the Critical Buckling Load of Symmetric Composite Laminated Plates

2012 ◽  
Vol 629 ◽  
pp. 95-99 ◽  
Author(s):  
N. Hamani ◽  
D. Ouinas ◽  
N. Taghezout ◽  
M. Sahnoun ◽  
J. Viña
Keyword(s):  
Fiber Orientation ◽  
Composite Plates ◽  
Laminated Plates ◽  
Buckling Load ◽  
The Finite Element Method ◽  
Notch Radius ◽  
Critical Buckling Load ◽  
Buckling Strength ◽  
Degree Of Anisotropy ◽  
Circular Notch

In this study, a buckling analysis is performed on rectangular composite plates with single and double circular notch using the finite element method. Laminated plates of carbon/bismaleimde (IM7/5250-4) are ordered symmetrically as follows [(θ/-θ)2]S. The buckling strength of symmetric laminated plates subjected to uniaxial compression is highlighted as a function of the fibers orientations. The results show that whatever the notch radius, the buckling load is almost stable. Increasing the degree of anisotropy significantly improves critical buckling load.

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