Analysis of Patch Bonded Repair to Carbon Fiber Composite Laminates with Low Velocity Impact Damage

2011 ◽  
Vol 335-336 ◽  
pp. 226-229
Author(s):  
Lun Wang ◽  
Wan Lin Zhou ◽  
Xue Gang Shi
Keyword(s):  
Carbon Fiber ◽  
Composite Laminates ◽  
Impact Damage ◽  
Fiber Composite ◽  
Element Model ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Carbon Fiber Composite ◽  
Velocity Impact ◽  
Bonded Repair

In this paper, low-velocity impact residual tensile strength of carbon fiber composite laminates are investigated by experiment. The triple-plate-string-element finite element model was used to calculate the strength of repaired structures of the damage. The corresponding strength tests were conducted to verify the computational results. According to the computational and experimental results, the influence of the repair parameters on the repair efficiency was analyzed, such as the overlap length and the thickness of the patch.

Damage Characterization of Carbon and Glass Fiber Composite Plates Subjected to Low-Velocity Impact Using Thermography

2018 ◽  
Author(s):  
Khaled S. Al-Athel ◽  
Ahmed Alomari ◽  
Abul Fazal M. Arif
Keyword(s):  
Glass Fiber ◽  
Composite Laminates ◽  
Impact Damage ◽  
Fiber Composite ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Damage Characterization ◽  
Post Impact

Composites are prone to delamination damage when impacted by low velocity projectiles because of the poor through-thickness strength. Therefore, some of the problems with composites are their poor impact damage resistance, weak post-impact mechanical properties, and the difficulty to inspect the impacted area by nondestructive means. Damage characterization of composite materials requires a scientific methodology, knowledge of polymeric materials, and direct field experience. In this work, low-velocity impact response of composite laminates was experimentally studied using drop-tower to determine the energy absorption. Three types of composites were used: carbon fiber, glass fiber, and mixed fiber composite laminates. In addition, these composites were characterized using thermography to quantify their post impact damage. It was found with the 3D temperature distribution that a strong correlation can be determined between the measured temperatures at the impact region with the quantification of the damage using thermal imaging with advanced mid-wave camera.

The Study of Low-Velocity Impact Characteristics and Residual Tensile Strength of Carbon Fiber Composite Lattice Core Sandwich Structures

2011 ◽  
Vol 194-196 ◽  
pp. 117-120 ◽  
Author(s):  
Xai Mei Lu ◽  
Yun Fei Ma ◽  
Shi Xun Wang
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Sandwich Structures ◽  
Fiber Composite ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Carbon Fiber Composite ◽  
Velocity Impact ◽  
Composite Lattice ◽  
Lattice Core

In this paper, low-velocity impact characteristics and residual tensile strength of carbon fiber composite lattice core sandwich structures are investigated experimentally and numerically. Low-velocity impact tests and residual tensile strength tests are simulated by the FE (finite element) software, ABAQUS/Explicit and its subroutine (VUMAT). In order to give more detailed description about the impact damage of the structure and improve modeling accuracy, multi-steps analysis method is employed to simulate impact process and residual tensile strength test in one analysis model. The calculation results computed by the FE model have been compared to the value of experiments, the difference of impact process simulation is about 3.3% and that of tensile strength test simulation is about 12.9%. The calculation error of computation model is acceptable, since unavoidable damage could be introduced in the courses of manufacture, processing and transportation of composite materials, and these damages are determinated difficultly in the computation programs. Next, the degradation tendency chart of residual tensile strength and impact energy threshold Uo of carbon fiber composite lattice core sandwich structures are obtained by the computation value of residual tensile strength after impacted with different impact energy. Previously, this threshold can only be obtained by experiment tests. After the contact force which is bigger than the threshold Uo impact on the sandwich structures, the residual tensile strength of structures are degraded greatly. This conclusion is significant for the design and application of carbon fiber composite lattice core sandwich structures.

Study on low-velocity impact and residual strength at high temperatures of composite laminates

2017 ◽  
Vol 233 (3) ◽  
pp. 1106-1123 ◽  
Author(s):  
Jingmeng Weng ◽  
Weidong Wen ◽  
Hongjian Zhang
Keyword(s):  
Compressive Strength ◽  
High Temperatures ◽  
Residual Strength ◽  
Composite Laminates ◽  
Impact Damage ◽  
Element Model ◽  
Low Velocity Impact ◽  
Cohesive Elements ◽  
Low Velocity ◽  
Velocity Impact

In this paper, low-velocity impact characteristics and residual tensile/compressive strength of composite laminates at high temperatures are experimentally and analytically investigated. Low-velocity impact tests at room temperature were performed using a drop-weight apparatus, and residual strength tests at high temperatures were performed using a hydraulic MTS machine. The experimental results show that both residual tensile and compressive strength decrease monotonically with the increase of impact energy, while the variation trend of residual tensile/compressive strength of composite laminates keeps the same with longitudinal tensile/compressive strength with the increase of temperature. In addition, a new stress-based delamination failure criterion was established, in which the delamination is considered to be controlled by the difference between through-thickness stresses of adjacent layers. Once delamination occurs, only the elements below the interface are marked with delamination, whereas the material properties of the elements on both sides of the interface are reduced simultaneously. In this way, delamination can be defined more precisely without cohesive elements, and a considerable reduction in CPU time can be achieved. Combined with extended Hashin failure criteria, an integrated finite element model was established to simulate low-velocity impact damage and to predict residual tensile and compressive strength of composite laminates. The numerical results show good agreements with experimental data.

scholarly journals Experimental and Computational Analysis of Low-Velocity Impact on Carbon-, Glass- and Mixed-Fiber Composite Plates

2020 ◽  
Vol 4 (4) ◽  
pp. 148
Author(s):  
Ahmed S. AlOmari ◽  
Khaled S. Al-Athel ◽  
Abul Fazal M. Arif ◽  
Faleh. A. Al-Sulaiman
Keyword(s):  
Composite Laminates ◽  
Impact Damage ◽  
Fiber Composite ◽  
Impact Resistance ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Damage Resistance ◽  
Velocity Impact ◽  
Delamination Damage

One of the problems with composites is their weak impact damage resistance and post-impact mechanical properties. Composites are prone to delamination damage when impacted by low-speed projectiles because of the weak through-thickness strength. To combat the problem of delamination damage, composite parts are often over-designed with extra layers. However, this increases the cost, weight, and volume of the composite and, in some cases, may only provide moderate improvements to impact damage resistance. The selection of the optimal parameters for composite plates that give high impact resistance under low-velocity impact loads should consider several factors related to the properties of the materials as well as to how the composite product is manufactured. To obtain the desired impact resistance, it is essential to know the interrelationships between these parameters and the energy absorbed by the composite. Knowing which parameters affect the improvement of the composite impact resistance and which parameters give the most significant effect are the main issues in the composite industry. In this work, the impact response of composite laminates with various stacking sequences and resins was studied with the Instron 9250G drop-tower to determine the energy absorption. Three types of composites were used: carbon-fiber, glass-fiber, and mixed-fiber composite laminates. Also, these composites were characterized by different stacking sequences and resin types. The effect of several composite structural parameters on the absorbed energy of composite plates is studied. A finite element model was then used to find an optimized design with improved impact resistance based on the best attributes found from the experimental testing.

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