Effect of gap and overlap fiber placement defects on the delamination behavior of L-shaped composite laminates

2021 ◽  
Vol 268 ◽  
pp. 113963
Author(s):  
Shimeng Qian ◽  
Xin Liu ◽  
Yaoyao Ye ◽  
Qiang Xu ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Fiber Placement ◽  
Delamination Behavior

scholarly journals Experimental Investigation on the Influence of Fiber Path Curvature on the Mechanical Properties of Composites

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2602
Author(s):  
Huaqiao Wang ◽  
Jihong Chen ◽  
Zhichao Fan ◽  
Jun Xiao ◽  
Xianfeng Wang
Keyword(s):  
Tensile Strength ◽  
Path Planning ◽  
Composite Laminates ◽  
Bending Strength ◽  
High Strength ◽  
Bending Test ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Fiber Path ◽  
Path Curvature

Automated fiber placement (AFP) has been widely used as an advanced manufacturing technology for large and complex composite parts and the trajectory planning of the laying path is the primary task of AFP technology. Proposed in this paper is an experimental study on the effect of several different path planning placements on the mechanical behavior of laminated materials. The prepreg selected for the experiment was high-strength toughened epoxy resin T300 carbon fiber prepreg UH3033-150. The composite laminates with variable angles were prepared by an eight-tow seven-axis linkage laying machine. After the curing process, the composite laminates were conducted by tensile and bending test separately. The test results show that there exists an optimal planning path among these for which the tensile strength of the laminated specimens decreases slightly by only 3.889%, while the bending strength increases greatly by 16.68%. It can be found that for the specific planning path placement, the bending strength of the composite laminates is significantly improved regardless of the little difference in tensile strength, which shows the importance of path planning and this may be used as a guideline for future AFP process.

Finite element study into the effects of fiber orientations and stacking sequence on drilling induced delamination in CFRP/Al stack

2018 ◽  
Vol 25 (3) ◽  
pp. 555-563 ◽  
Author(s):  
Gong-Dong Wang ◽  
Stephen Kirwa Melly ◽  
S.K. Kafi Ahmed
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Research Work ◽  
Stacking Sequence ◽  
Finite Element Code ◽  
Model Surface ◽  
Shell Elements ◽  
Push Down ◽  
The Individual ◽  
Delamination Behavior

Abstract This research work has been aimed at understanding the effects of different fiber orientations and different stacking sequences of composite laminates on their damage during drilling of CFRP/Al stack. Finite element code Abaqus/CAE has been used for the implementation and analysis of the numerical model. Surface-based cohesive behavior available in Abaqus/CAE contact pairs has been used to simulate delamination behavior in the adhesive interfaces. In order to use the Hashin damage criterion (for intra-laminar damage) available in the finite element code, continuum shell elements have been used for laminates. Three stacking sequences each with 24 layers including [0°]24, [0°/90°]12s, and [−45°/90°4/45°2/−45°]3s have been considered for this study. The display group manager available in Abaqus/CAE visualization module enabled the individual access of the damage in each layer. Two layers both at drill entry and at CFRP/Al interface were used to study peel-up and push-down delamination, respectively. Sequence [0°]24 was found to have the largest damaged in both entry and interfaces, while sequence [−45°/90°4/45°2/−45°]3s was found to show better resistance to delamination damage.

Ultrasonic Detection of Fiber Orientation in Composite Laminates for Use of Vehicular Structures

2005 ◽  
Vol 297-300 ◽  
pp. 2109-2114
Author(s):  
Je Woong Park ◽  
Kwang Hee Im ◽  
David K. Hsu ◽  
Seung Woo Na ◽  
Young Nam Kim ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Composite Laminates ◽  
Azimuthal Angle ◽  
Normal Incidence ◽  
Test Results ◽  
Ultrasonic Signals ◽  
Fiber Placement ◽  
Reinforced Plastics ◽  
Vector Decomposition ◽  
Optical Test

The layup of a CFRP (carbon-fiber reinforced plastics) composite laminates affects the properties of the laminate, including stiffness, strength and thermal behavior. It is very important to detect ply error before the laminate is cured for both manual procedure and fiber placement procedure. An ultrasonic technique would be very beneficial, which could be used to test the part after and before curing laminates and requires less time than the optical test. Also cross-polarized scan is very sensitive to the layup errors and ply misorientations. Scanners were set out for different measurement modalities for acquiring ultrasonic signals as a function of in-plane azimuthal angle. Firstly, a manual scanner was built for making transmission measurements using a pair of normal-incidence shear wave transducers to find the effect of fiber misorientations of composite laminates. Also a method for nondestructively determining the ply layup in a composite laminate is presented. The method employs a normal-incidence longitudinal ultrasound to perform C-scan of ply interfaces of the laminate. And a ply-by-ply vector decomposition model has been utilized for evaluating layup errors in composite laminates fabricated from unidirectional plies. Test results between after and before curing laminates with model data were compared for a fiber orientation of the laminates.

scholarly journals Optimizing Variable-Axial Fiber-Reinforced Composite Laminates: The Direct Fiber Path Optimization Concept

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lars Bittrich ◽  
Axel Spickenheuer ◽  
José Humberto S. Almeida ◽  
Sascha Müller ◽  
Lothar Kroll ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Variable Stiffness ◽  
Tensile Specimen ◽  
Path Optimization ◽  
Fiber Reinforced ◽  
Simulation And Optimization ◽  
Fiber Placement ◽  
Fiber Path ◽  
Curvilinear Fibers ◽  
Novel Concept

The concept of aligning reinforcing fibers in arbitrary directions offers a new perception of exploiting the anisotropic characteristic of the carbon fiber-reinforced polymer (CFRP) composites. Complementary to the design concept of multiaxial composites, a laminate reinforced with curvilinear fibers is called variable-axial (also known as variable stiffness and variable angle tow). The Tailored Fiber Placement (TFP) technology is well capable of manufacturing textile preforming with a variable-axial fiber design by using adapted embroidery machines. This work introduces a novel concept for simulation and optimization of curvilinear fiber-reinforced composites, where the novelty relies on the local optimization of both fiber angle and intrinsic thickness build-up concomitantly. This framework is called Direct Fiber Path Optimization (DFPO). Besides the description of DFPO, its capabilities are exemplified by optimizing a CFRP open-hole tensile specimen. Key results show a clear improvement compared to the current often used approach of applying principal stress trajectories for a variable-axial reinforcement pattern.

Bridging effect on mode I fatigue delamination behavior in composite laminates

2014 ◽  
Vol 63 ◽  
pp. 103-109 ◽  
Author(s):  
Liaojun Yao ◽  
René Alderliesten ◽  
Meiying Zhao ◽  
Rinze Benedictus
Keyword(s):  
Composite Laminates ◽  
Mode I ◽  
Delamination Behavior

Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

2021 ◽  
pp. 002199832110316
Author(s):  
Mohammadhossein Ghayour ◽  
Mehdi Hojjati ◽  
Rajamohan Ganesan
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Structural Integrity ◽  
Mechanical Response ◽  
Defect Layer ◽  
Damage Analysis ◽  
Manufacturing Defects ◽  
Fiber Placement ◽  
Layer Method ◽  
Automated Fiber Placement

Automated manufacturing defects are new types of composite structure defects induced during fiber deposition by robots. Fiber tow gap is one of the most probable types of defects observed in the Automated Fiber Placement (AFP) technique. This defect can affect the structural integrity of structures by reducing structural strength and stiffness. The effect of this defect on the mechanical response of the composite laminates has been investigated experimentally in the literature. However, there is still no efficient numerical/analytical method for damage assessment of composite structures with distributed induced gaps manufactured by the AFP technique. The present paper aims to develop the Induced Defect Layer Method (IDLM), a new robust meso-macro model for damage analysis of the composite laminates with gaps. In this method, a geometrical parameter, Gap Percentage (GP), is implemented to incorporate the effect of induced-gaps in the elastic, inelastic, and softening behavior at the material points. Thus, while the plasticity and failure of the resin pockets in conjunction with intralaminar composite damages can be evaluated by this method, the defective areas are not required to be defined as resin elements in the Finite Element (FE) models. It can also be applied for any arbitrary distributions of the defects in the multi-layer composite structures, making it a powerful tool for continuum damage analysis of large composite structures. Results indicate that the proposed method can consider the effect of gaps in both elastic and inelastic behavior of the composite laminate with defects. It also provides good agreement with the experimental results.

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