Article
Chemistry, Physical
Binkai Li, Yu Gong, Yukui Gao, Mengqing Hou, Lei Li
Summary: This study conducted experimental and numerical research on the static and fatigue failure of hat-stringer-stiffened composite panels under four-point bending loading. A novel theoretical model was proposed and a numerical method was developed for accurate prediction. The results showed good agreement between predictions and experiments.
Article
Engineering, Civil
Wenbin Zhou, Zhusheng Shi, Qi Rong, Xuepiao Bai, Yuansong Zeng, Jianguo Lin
Summary: Experimental and numerical studies have been conducted on the buckling behaviour of stiffened panels under four point bending during creep age forming (CAF) for the first time in this research. The results obtained from experiments and finite element simulations show that the buckling mode, strain distribution, and strain evolution of the stiffened panel can be accurately predicted using the non-linear FE method. The findings of this study can be used to guide the structural design of stiffened panels in cold forming and CAF processes.
THIN-WALLED STRUCTURES
(2022)
Article
Optics
Jun Guo, Weidong Li, Min Wan, Yue Zhao, Cailing Li
Summary: The study proposed the use of laser-assisted four-point bending to form high-stiffened structures of aluminum alloy, finding that the increase in plastic strain was mainly attributed to the elastic strain of the laser scanned area and the bullying effect of adjacent areas. It was demonstrated through simulation and experiment that LAFPB can reduce mechanical force and springback by converting elastic strain energy into plastic strain energy inside the part, leading to improved forming quality.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Engineering, Multidisciplinary
Honglei Xie, Chunyan Shen, Hai Fang, Juan Han, Wei Cai
Summary: This study focused on the flexural property of PET foam-filled lattice composite sandwich panels under four-point bending. Increasing the thickness of face sheet and PET foam can effectively improve the ultimate load of the panels. Experimental results and theoretical predictions showed errors within 10% for bending stiffness and ultimate load.
COMPOSITES PART B-ENGINEERING
(2022)
Article
Metallurgy & Metallurgical Engineering
Han-wei Li, Hong-wu Song, Shi-hong Zhang, Li Wan, Chun-li Jia, Xue-ting Chai, Guo-wei Zhang, Lucian Lazarescu, Dorel Banabic
Summary: This study investigated the filling roll bending process of a 2A12 aluminum alloy integral panel with polypropylene as filler. The operating effect of the filler was revealed through analytical, numerical, and experimental methods. The results showed that the filler reduced the position difference of the neutral layer between the ribs and the web of the integral panel, thereby improving the generatrix straightness. The width gap between the filler and rib within a certain range (1-3 mm) prevented instability and curling. The compression degree of the filler was determined by the height gap, with the best pressure transmission achieved when the filler exceeded the rib by 1 mm after compression.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2023)
Article
Engineering, Aerospace
Wenbin Zhou, Zhusheng Shi, Yong Li, Qi Rong, Yuansong Zeng, Jianguo Lin
Summary: A new method is proposed in this study for the elastic-plastic buckling analysis of stiffened panels under global bending. Finite element modeling was carried out to study the buckling behavior, with results showing good agreement between FE and DT results and the effects of geometric parameters were analyzed.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Mechanics
Qianqian Wu, Shaojie Hu, Xiaohan Tang, Xin Liu, Zongbing Chen, Jian Xiong
Summary: The compressive buckling and post-buckling behaviors of J-type composite stiffened panels before and after impact load were investigated through theoretical, numerical, and experimental methods. The load-bearing characteristics of intact and damaged panels were predicted and tested, and the effects of impact damage on panel behavior were revealed through numerical simulation. The study also examined the influence of adhesive layer, lay-up method, and geometric dimensions on structural behavior. The research provides useful suggestions for improving panel performance.
COMPOSITE STRUCTURES
(2023)
Article
Mechanics
Jiu-Tao Hang, Wei Zhao, Lei Liu, Guang-Kui Xu
Summary: In this study, the damage sensitivity of a composite honeycomb sandwich structure with face-core de-bonding defects or impact damage was evaluated through in-plane compression, 4-point bending experiments, and FEM simulations. It was found that the structure is more sensitive to impact damage than to de-bonding defects. Impact damage with an energy range of 3 J-5.5 J can significantly change the failure mode and reduce the strength of the structure, while de-bonding defects of the same size only cause a minor decrease in strength. The developed FEM model accurately predicts the failure modes and residual strengths observed in experiments, indicating that the structural characteristics during impact loading are the main contributors to structural failure. Our model provides a useful tool for studying the mechanical behaviors of honeycomb sandwich structures.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Civil
Longquan Liu, Wenjun Xu
Summary: This study investigates the impact of fillers on the mechanical properties of hat-stiffened composite skin through experimental and numerical simulations. The results show that the use of fillers can enhance the impact resistance and failure load of the hat-stiffened composite skin.
THIN-WALLED STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Kai Qiao, Xiwu Xu, Tinh Quoc Bui, Tao Sun, Chao Zhang
Summary: A hierarchical coupled multiscale method is developed to capture the onset and propagation of damage within the 3D4D braided composites under bending loading. The macroscopic nonlinear behavior and the progressive damage response of the mesoscale architecture are solved iteratively using a two-scale coupled scheme. The results show that the braiding angle has a significant effect on the bending performance of 3D4D braided composites.
MECHANICS OF ADVANCED MATERIALS AND STRUCTURES
(2023)
Article
Engineering, Aerospace
Longquan Liu, Zhongwei Guan
Summary: This study investigates the compressive buckling and post-buckling processes of large stiffened composite panels with hat-stiffeners, with or without fillers, through experimental tests and finite element simulations. The results show that the use of fillers increases the buckling load, buckling strain, and collapse load of the panels. Additionally, the stiffness of the stiffeners is enhanced, delaying the buckling and altering the compressive failure process. This research provides valuable insights for the design of stiffened composite structures.
INTERNATIONAL JOURNAL OF AERONAUTICAL AND SPACE SCIENCES
(2023)
Article
Engineering, Civil
J. F. Castillo-Lara, E. A. Flores-Johnson, A. Valadez-Gonzalez, P. J. Herrera-Franco, J. G. Carrillo, P. Gonzalez-Chi, E. Agaliotis, Q. M. Li
Summary: The study reported the four-point bending behavior of composite sandwich panels with fibre-reinforced foamed concrete (FRFC) cores, showing that FRFC cored panels had greater initial failure load, maximum load, and energy absorption compared to plain foamed concrete (PFC) cored panels. This improvement was attributed to the enhanced ductility and toughness of the FRFC cores due to fibre reinforcement, with energy absorbing mechanisms including cracks development in the FC core, face wrinkling, and face-core debonding. Finite element simulations highlighted the crucial role of face-core bonding in the structural performance of the panels, suggesting further investigations on the use of natural-fibre reinforced cores in sandwich panels for construction applications.
THIN-WALLED STRUCTURES
(2021)
Article
Engineering, Multidisciplinary
Guoqiang Liu, Binwen Wang, Li Wang, Yu Yang, Xiaguang Wang
Summary: The probability-based diagnostic imaging (PDI) algorithm is suitable for damage identification of complex composite structures, but its weight distribution function is relatively inaccurate, affecting damage localization accuracy. An improved PDI algorithm is proposed to correct this issue by adjusting the weight distribution function, resulting in improved accuracy in identifying damages on stiffened composite panels.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2022)
Article
Construction & Building Technology
Hongliang Liu, Liang-jiu Jia
Summary: This study re-evaluates the four-point bending test method for structural glass by considering the effects of boundary conditions and friction. Results show that different boundary conditions can deviate from the standard method and it is recommended to ensure free rotation of supporting and bending rollers during the test.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Mechanics
Denis A. Ferreira, Rafael Savioli, Diego F. B. Sarzosa
Summary: This study presents a new complete procedure to characterize fracture toughness in Mode I loading using four-point bend specimens. Through extensive experimental and 3D finite element analysis, accurate estimation of fracture toughness parameters valid for four-point bend specimens is achieved. The results show that four-point bend specimens provide reliable fracture toughness values somewhat higher than three-point bend geometries.
ENGINEERING FRACTURE MECHANICS
(2021)