Article
Materials Science, Composites
Bing Zhang, Stephen R. Hallett, Giuliano Allegri
Summary: This paper explores a novel technique for sensing delamination in through-thickness reinforced composites using electromagnetic induction. By utilizing ferromagnetic Z-pins and coils, this method is able to avoid potential interferences from contact electrical resistances and has been demonstrated to be viable in bridging tests. The sensitivity of the magnetic-based sensing technique increases with loading rate and is capable of detecting both mode I and mode II delamination events.
COMPOSITES SCIENCE AND TECHNOLOGY
(2022)
Article
Mechanics
Andre Knopp, Elisabeth Funck, Andreas Holtz, Gerhard Scharr
Summary: The investigations conducted in this study demonstrate that the properties of z-pin reinforced laminates can be positively influenced by using circumferentially notches as a defined z-pin surface micro-structuring. The fracture mechanical properties under Mode-I crack opening loading can be significantly improved and the resulting delamination areas that occur during an impact can be effectively reduced. The residual strength properties of pinned laminates are also more favorable and can be further enhanced with the use of circumferentially notched z-pins.
COMPOSITE STRUCTURES
(2022)
Article
Materials Science, Composites
Andre Knopp, Gerhard Scharr
Summary: This study demonstrates that notching of z-pins significantly increases the compression strength of laminates, with different notch designs impacting the results but not affecting the Young's modulus.
COMPOSITES SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Composites
Mudan Chen, Bing Zhang, Sven Friedemann, Giuliano Allegri, Stephen R. Hallett
Summary: This study investigates the effects of Z-pins on the magnetic properties of composite laminates, showing that carbon-fiber pins have little influence while Ni/Fe alloy pins increase the laminate magnetic susceptibility. The out-of-plane susceptibility exhibits nonlinear behavior dependent on the pin volume fraction, while saturation magnetization is proportional to the pin volume fraction.
COMPOSITES SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Composites
Yuchi Liu, Licheng Cai, Huiming Ding, Qiang Xu
Summary: This study investigated the effects of Z-pin content and insertion angle on the deformation and failure of quasi-isotropic laminates in the thickness direction. The experimental results showed that as the Z-pin insertion angle increased, the maximum pull-out force and maximum friction force decreased, and interfacial debonding became the dominant failure mode. Z-pin insertion had little effect on the global failure mode of the laminates.
APPLIED COMPOSITE MATERIALS
(2023)
Article
Engineering, Manufacturing
T. W. Loh, R. B. Ladani, A. Ravindran, R. Das, E. Kandare, A. P. Mouritz
Summary: The addition of thermoplastic mendable filaments in z-pinned composites can greatly increase interlaminar fracture toughness, repair delamination damage, and enhance crack propagation resistance. This novel repair process has the potential application for various types of composites with through-thickness reinforcement.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2021)
Article
Engineering, Manufacturing
E. Santana de Vega, G. Allegri, B. Zhang, I. Hamerton, S. R. Hallett
Summary: This paper presents a characterization of the effect of varying the polymer matrix in Z-pin through-thickness reinforcement in pre-preg based laminates. The experimental results indicate that Z-pins with a high elongation at break, such as LTG Z-pins, exhibit superior bridging performance and toughness.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2022)
Article
Materials Science, Composites
Zhe Che, Min Li, Shuo Wang, Shaokai Wang, Yizhuo Gu, Wei Zhang
Summary: This study improves the shear delamination resistance of composite laminate and enhances crack propagation resistance by using fine z-pins. The results demonstrate that z-pinning plays a significant role in improving interlaminar fracture toughness, and decreasing the z-pin diameter further enhances the resistance to crack propagation.
POLYMER COMPOSITES
(2022)
Article
Materials Science, Composites
Abhinav Omprakash Fulmali, Satyaroop Patnaik, Dinesh Kumar Rathore, Debashish Bhattacharjee, Bharat Gwalani, Bankim Chandra Ray, Rajesh Kumar Prusty
Summary: A z-directional nanoreinforcement approach was implemented to improve the mechanical performance of laminated composites under extreme temperature conditions. The composites with aligned functionalized carbon nanotubes (A-FCNT) consistently outperformed other composites in terms of flexural and interlaminar shear strength at all considered temperatures. The improved viscoelastic properties of the A-FCNT composite were attributed to the synergetic impact of functionalization and alignment.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
Yinhuan Yang, Manfeng Gong, Xiaoqun Xia, Linzhi Wu
Summary: The mechanical properties of Z-pins reinforced composites adhesively bonded single-lap joints under unidirectional tension loading are studied. Different joint configurations are investigated and the failure modes and strengths are compared between joints with and without Z-pins. The results show that the presence of Z-pins improves the strength of the joints by 16% and the numerical simulation is consistent with experimental results.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2022)
Article
Engineering, Manufacturing
S. Abbasi, R. B. Ladani, C. H. Wang, A. P. Mouritz
Summary: The study investigates the mechanisms and effectiveness of metallic and composite z-filaments in improving the interlaminar fatigue resistance of fibre-polymer laminates. Results show that steel z-filaments are more effective than copper filaments in resisting fatigue crack initiation and growth under interlaminar cyclic loads. Differences in crack bridging efficiency under interlaminar fatigue loading contribute to the varying extents of improvement provided by the three filaments.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2021)
Article
Materials Science, Composites
Xiaoxu Wang, Wen Chen, Youhong Tang
Summary: Z-pin pull-out tests were conducted to investigate the meso interface structure and debonding position of the z-pin/laminate system. The results revealed that the interface consisted of two meso interface components, with debonding occurring at the weaker one. The z-pin with better molding quality exhibited higher interfacial bond shear stress and debonding primarily occurred at Interface I, while the z-pin with poorer molding quality had lower interfacial bond shear stress and debonding mainly occurred at Interface II. However, this type of z-pin showed higher resistance at the final frictional pull-out stage.
COMPOSITES COMMUNICATIONS
(2022)
Article
Mechanics
Mark McElroy, Alann Andre, Tyler Goode, Sergio Costa, Robin Olsson, Mark Pankow
Summary: This paper introduces an enhanced shell element for simulating low-velocity impact damage in composite laminates, which is computationally more efficient than high-fidelity models. The enriched element utilizes the Floating Node Method and a damage algorithm based on the Virtual Crack Closure Technique to simulate progressive damage growth. Results from test-analysis correlation for impact testing of laminates are presented, demonstrating the potential accuracy of the shell model for a wide range of engineering applications.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Manufacturing
Hamed Fallahi, Ozge Kaynan, Amir Asadi
Summary: This study experimentally investigates the influence of the fiber-matrix interphase on the fracture toughness of fiber-reinforced composites. The width and chemical properties of the interphase zone are found to significantly affect the interfacial strength. By modifying the fiber surface with nanoparticles, the interfacial strength is improved by 76%, resulting in a more effective contribution of the matrix during fracture. This stronger interphase leads to a 183% improvement in mode I and 75% improvement in mode II interlaminar fracture toughness of the composite.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2023)
Article
Engineering, Multidisciplinary
Philipp Hahn, Harichandana Channammagari, Mathieu Imbert, Michael May
Summary: This paper presents a novel high-rate transverse crack tension (TCT) test for determining mode II fracture toughness under high strain rates. The results show that the fracture toughness of the tested composite under high-rate loading is at least 50% higher compared to quasi-static loading.
COMPOSITES PART B-ENGINEERING
(2022)