CFRP barely visible impact damage inspection based on an ultrasound wave distortion indicator

2019 ◽  
Vol 168 ◽  
pp. 152-158 ◽  
Author(s):  
Xiaofei Zhang ◽  
Xuan Wu ◽  
Yunze He ◽  
Shuming Yang ◽  
Sheng Chen ◽  
...  
Keyword(s):  
Impact Damage ◽  
Ultrasound Wave ◽  
Wave Distortion

Analyses and experimental study about impact damage of COPV

2018 ◽  
Vol 12 (4) ◽  
pp. 302
Author(s):  
Daolian Wang ◽  
Chuanjun Liao ◽  
Wenqiang Li ◽  
Haoran Lu
Keyword(s):  
Experimental Study ◽  
Impact Damage

scholarly journals Hygrothermal Ageing Influence on BVI-Damaged Carbon/Epoxy Coupons under Compression Load

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2038
Author(s):  
Maria Pia Falaschetti ◽  
Matteo Scafé ◽  
Nicola Zavatta ◽  
Enrico Troiani
Keyword(s):  
Residual Strength ◽  
Impact Damage ◽  
Mechanical Analysis ◽  
Test Method ◽  
Combined Loading ◽  
Compression Load ◽  
Impact Location ◽  
Hygrothermal Ageing ◽  
Influence Of Water ◽  
Compressive Tests

Composite materials usage in several industrial fields is now widespread, and this leads to the necessity of overcoming issues that are still currently open. In the aeronautic industry, this is especially true for Barely Visible Impact Damage (BVID) and humidity uptake issues. BVID is the most insidious kind of impact damage, being rather common and not easily detectable. These, along with the ageing that a composite structure could face during its operative life, could be a cause of fatal failures. In this paper, the influence of water absorption on impacted specimens compressive residual strength was studied. Specimens were impacted using a modified Charpy pendulum. Two different locations were chosen for comparison: Near-Edge (NE) and Central (CI). Accelerated hygrothermal ageing was conducted on impacted and reference nonimpacted coupons, placing them in a water-filled jar at 70 °C. Compressive tests were performed in accordance with the Combined Loading Compression (CLC) test method. A Dynamic Mechanical Analysis (DMA) was performed as well. The results showed the influence of hygrothermal ageing, as expected. Nevertheless, the influence of impact location on compressive residual strength is not clearly noticeable in aged specimens, leading to the conclusion that hygrothermal ageing may have a greater effect on composite compressive strength than the analysed BVI damage.

scholarly journals Numerical Investigation on the Ultimate Strength of Box Beams with Impact Damage

2020 ◽  
Author(s):  
Wei Xu ◽  
C. Guedes Soares
Keyword(s):  
Residual Stress ◽  
Ultimate Strength ◽  
Impact Damage ◽  
Ship Hulls ◽  
Four Point Bending ◽  
Impact Location ◽  
Box Beam ◽  
Box Beams ◽  
Fracture Damage ◽  
The Impact

AbstractThe objective of this paper is to study the residual ultimate strength of box beams with impact-induced damage, as a model of what may occur in ship hulls. The bottom and side plates of ship hulls can suffer denting or fracture damage due to grounding, collision and other contacts during the ship’s service life and these impact-induced damages could result in considerable strength degradation. Box beams are firstly subjected to impact loading and then four-point bending loading is imposed on the damaged structures to assess the residual strength using ANSYS/LS_DYNA. The ultimate moment and collapse modes are discussed considering the effect of impact location. The impact-induced deformation is introduced in the four-point bending simulation, and the impact-induced stress is included or not to determine the effect of residual stress and distortion after impact. It is shown that impact location has significant influence on the residual ultimate bending moment of the damaged box beam providing that the impact energy is kept constant. The collapse modes also change when the impactor strikes on different locations. Damaged hard corner and inclined neutral axes might explain the reduction of ultimate strength and diverse collapse modes. The residual stress in the box beam after impact may increase or decrease the ultimate strength depending on impact location.

scholarly journals Fast and simple detection of impact damage

2020 ◽  
Author(s):  
Johannes Rittmann ◽  
Markus Rahammer ◽  
Niels Holtmann ◽  
Marc Kreutzbruck
Keyword(s):  
Impact Damage ◽  
Simple Detection

Investigation of the mechanical and forming behaviour of 3D warp interlock carbon woven fabrics for complex shape of composite material

2021 ◽  
pp. 152808372098410
Author(s):  
Mehmet Korkmaz ◽  
Ayşe Okur ◽  
Ahmad Rashed Labanieh ◽  
François Boussu
Keyword(s):  
Composite Materials ◽  
Complex Shape ◽  
Impact Damage ◽  
Woven Fabrics ◽  
Forming Process ◽  
Warp Yarn ◽  
Delamination Resistance ◽  
Fabric Architecture ◽  
Weave Pattern ◽  
Carbon Fabrics

Composite materials which are reinforced with 3D warp interlock fabrics have outstanding mechanical properties such as higher delamination resistance, ballistic damage resistance and impact damage tolerance by means of their improved structural properties. Textile reinforcements are exposed to large deformations in the production stage of composite materials which have complex shape. Although good formability properties of 3D warp interlock fabrics in forming process were already proven by recent studies, further information is needed to elucidate forming behaviours of multi-layer fabrics which is produced with high stiffness yarns like carbon. In this study, 3D warp interlock carbon fabrics were produced on a prototype weaving loom and the same carbon yarn was used in two fabric directions with equal number of yarn densities. Fabrics were differentiated with regard to the presence of stuffer warp yarn, weave pattern and parameters of binding warp yarn which are angle and depth. Therefore, the effect of fabric architecture on the mechanical and formability properties of 3D warp interlock carbon fabrics could be clarified. Three different breaking behaviours of fabrics were detected and they were correlated with crimp percentages of yarn groups. In addition, the bending and shear deformations were analysed in view of parameters of fabric architectures. Two distinct forming behaviours of fabrics were determined according to the distribution of deformation areas on fabrics. Moreover, the optimal structure was identified for forming process considering the fabric architecture.

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