Interlaminar Stresses in Composite Laminates Subjected to Twisting Deformation

2017 ◽  
Vol 84 (10) ◽  
Author(s):  
Johnathan Goodsell ◽  
Bo Peng ◽  
R. Byron Pipes ◽  
Wenbin Yu
Keyword(s):  
Composite Laminates ◽  
Load Transfer ◽  
Interlaminar Stresses ◽  
Thermoelastic Deformation ◽  
Interlaminar Stress ◽  
Bending Deformation ◽  
Axial Extension ◽  
The Cross ◽  
Twisting Deformation

The interlaminar stress in angle-ply and cross-ply composite laminates subjected to twisting deformation are investigated. Two mechanisms of interlaminar load transfer have been developed by studying the angle-ply laminate and the cross-ply laminate subjected to uniform axial extension, thermoelastic deformation and anticlastic bending deformation. In the present, these mechanisms are investigated in laminates subjected to twisting deformation. It is shown that the mechanisms of interlaminar load transfer in twisting deformation are identical to those previously investigated, though they arise from different causes. Furthermore, a unified treatment of the mechanisms of interlaminar load transfer is presented for the angle-ply laminate and the cross-ply laminate subjected to the four aforementioned modes of deformation.

A Preliminary Study on the Mechanical Performance of Tiled Polymer Composites

2006 ◽  
Author(s):  
M. A. Qidwai ◽  
J. N. Baucom ◽  
A. C. Leung ◽  
J. P. Thomas
Keyword(s):  
Composite Laminates ◽  
Load Transfer ◽  
Mechanical Performance ◽  
Local Stress ◽  
Superior Performance ◽  
Design Parameters ◽  
Interlaminar Stresses ◽  
Stress Concentrations ◽  
Critical Design ◽  
Composite Joint

We are developing and exploring the concept of in-plane tiling of composite laminates, called MOSAIC, to mitigate or control delamination at free edges due to interlaminar stresses. Initial mechanical testing has shown that MOSAIC composites with uniaxial graphite-fiber reinforced tiles retain the stiffness levels of traditional uniaxially reinforced composites but with reduced strength. The reduction in strength is attributed to the formation of resin-rich pockets between adjacent tiles. In this study, we have performed detailed finite element analyses to identify the critical design parameters that affect the mechanical performance of uniaxially reinforced MOSAIC composites. We have found that using continuous laminae on the outer surfaces significantly increases the overall loadcarrying capacity. Increasing aspect ratio of the pocket and decreasing material property differences between resin and tiles also cause better load transfer between tiles but may not necessarily improve overall strength due to increasing stress concentration. The tiling scheme and density of pocket placement influence the interaction of local stress concentrations. Consequently, a novel composite joint is proposed and found to have superior performance.

Interlaminar stresses in composite laminates: Thermoelastic deformation

2010 ◽  
Vol 70 (11) ◽  
pp. 1605-1611 ◽  
Author(s):  
R. Byron Pipes ◽  
Johnathan Goodsell ◽  
Andrew Ritchey ◽  
Joshua Dustin ◽  
Jonathan Gosse
Keyword(s):  
Composite Laminates ◽  
Interlaminar Stresses ◽  
Thermoelastic Deformation

Interlaminar Stresses in Composite Laminates Subjected to Anticlastic Bending Deformation

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Johnathan Goodsell ◽  
Nicholas J. Pagano ◽  
Oleksandr Kravchenko ◽  
R. Byron Pipes
Keyword(s):  
Boundary Layer ◽  
Temperature Change ◽  
Plate Theory ◽  
Finite Width ◽  
Uniform Temperature ◽  
Interlaminar Stresses ◽  
Poisson Effect ◽  
Bending Deformation ◽  
Axial Extension ◽  
Deformation State

Approximate elasticity solutions for prediction of the displacement, stress, and strain fields within the m-layer, symmetric and balanced angle-ply composite laminate of finite-width and subjected to uniform axial extension and uniform temperature change were developed earlier by the authors. In the present paper, the authors have extended these solutions to treat bending deformation. Bending and torsion moments are combined to yield a deformation state without twisting curvature and with transverse curvature due only to the laminate Poisson effect. This state of deformation is termed anticlastic bending. The approximate elasticity solution for this bending deformation is shown to recover laminated plate theory predictions at interior regions of the laminate and thereby illustrates the boundary layer character of this interlaminar phenomenon. The results exhibit the anticipated response in congruence with the solutions for uniform axial extension and uniform temperature change, where divergence of the interlaminar shearing stress is seen to occur at the intersection of the free edge and planes between lamina of +θ and –θ orientation. The analytical results show excellent agreement with the finite-element predictions for the same boundary-value problem and thereby provide an efficient and compact solution available for parametric studies of the influence of geometry and material properties. Finally, the solution was exercised to determine the dimensions of the boundary layer in bending for very large numbers of layers.

scholarly journals Evaluation of Interlaminar Stresses in Composite Laminates with a Bolt-Filled Hole Using a Linear Elastic Traction-Separation Description

2017 ◽  
Vol 7 (1) ◽  
pp. 93
Author(s):  
Yong Cao ◽  
Yunwen Feng ◽  
Xiaofeng Xue ◽  
Wenzhi Wang ◽  
Liang Bai
Keyword(s):  
Composite Laminates ◽  
Interlaminar Stresses ◽  
Linear Elastic

Fabrication, modeling, and characterization of soft twisting electrothermal actuators with directly printed oblique heater

2022 ◽  
Author(s):  
Yang Cao ◽  
Jingyan Dong
Keyword(s):  
Kinematic Model ◽  
Design Parameters ◽  
Deformation Analysis ◽  
Pdms Layer ◽  
Element Analysis ◽  
Electrothermal Actuators ◽  
Bending Deformation ◽  
Heating Capacity ◽  
Twisting Angle ◽  
Twisting Deformation

Abstract Soft electrothermal actuators have drawn extensive attention in recent years for their promising applications in biomimetic and biomedical areas. Most soft electrothermal actuators reported so far demonstrated uniform bending deformation, due to the deposition based fabrication of the conductive heater layer from nanomaterial-based solutions, which generally provides uniform heating capacity and uniform bending deformation. In this paper, a soft electrothermal actuator that can provide twisting deformation was designed and fabricated. A metallic microfilament heater of the soft twisting actuator was directly printed using electrohydrodynamic (EHD) printing, and embedded between two structural layers, a polyimide (PI) film and a polydimethylsiloxane (PDMS) layer, with distinct thermal expansion properties. Assisted by the direct patterning capabilities of EHD printing, a skewed heater pattern was designed and printed. This skewed heater pattern not only produces a skewed parallelogram-shaped temperature field, but also changes the stiffness anisotropy of the actuator, leading to twisting deformation with coupled bending. A theoretical kinematic model was built for the twisting actuator to describe its twisting deformation under different actuation effects. Based on that model, influence of design parameters on the twisting angle and motion trajectory of the twisting actuator were studied and validated by experiments. Finite element analysis (FEA) was utilized for the thermal and deformation analysis of the actuator. The fabricated twisting actuator was characterized on its heating and twisting performance at different supply voltages. Using three twisting actuators, a soft gripper was designed and fabricated to implement pick-and-place operations of delicate objects.

Damage Control in Composite Laminates

2001 ◽  
Author(s):  
Alexander P. Suvorov ◽  
George J. Dvorak
Keyword(s):  
Composite Laminates ◽  
Composite Laminate ◽  
Damage Control ◽  
Thermomechanical Loading ◽  
Interlaminar Stresses ◽  
Damage Resistance ◽  
Viscoelastic Composite ◽  
Mechanical Loads ◽  
Composite Damage ◽  
The Matrix

Abstract Several effects that fiber prestress may have on stress redistribution in the plies of composite laminates and in the phases of individual plies are illustrated. These include improvement of composite damage resistance under tensile mechanical loads, reduction/cancelation of interlaminar stresses at free edges of composite laminate subjected to thermomechanical loading, and stress relaxation in the matrix phase of viscoelastic composite laminates. Specific results are found for quasi-isotropic and cross-ply symmetric S-glass/epoxy and carbon/epoxy AS4/EPON 828 laminates.

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