This paper reports the effects of fiber breakage defects and waviness defects on the compressive fatigue behavior and the progressive damage evolution process of 3D Multiaxial Braided Composites (3DMBCs). Combined wit...This paper reports the effects of fiber breakage defects and waviness defects on the compressive fatigue behavior and the progressive damage evolution process of 3D Multiaxial Braided Composites (3DMBCs). Combined with finite element compression simulation and ultra-depth microscope, the internal defect content of composites with different braiding angles was determined. The results demonstrate that the weakening effect of waviness and fiber breakage defects is greater than the strengthening effect of the braiding angle. This causes the fatigue resistance of 3DMBCs with the 31° braiding angle being better in both directions of 0° and 90°. The increase of 4° waviness and 10% fiber breakage defect results in the average fatigue life of composites being shortened by 48% and the energy consumption rate increased by 10% at 85% stress level in 90° compression direction. The alteration in loading direction modifies the included angle corresponding to the stress component. The stress component parallel to the fiber direction under compressive fatigue load leads to interfacial debonding in the composites, whereas the stress component perpendicular to the fiber direction results in pronounced shear failure.展开更多
The multidisciplinary space environment,encompassing orbital debris,cosmic radiation,and solar radiative heat,poses significant risks to spacecraft and astronauts,necessitating efficient and effective shielding soluti...The multidisciplinary space environment,encompassing orbital debris,cosmic radiation,and solar radiative heat,poses significant risks to spacecraft and astronauts,necessitating efficient and effective shielding solutions.A multi-layer shield with wide spacing has been proven to be an effective way to shield the spacecraft from space debris impact;however,due to the limited volume of the payload fairing,it was not feasible to apply a multi-layer shield to the spacecraft fuselage.Through the origami design,the shield maintains a compact form during launch and subsequently expands in outer space to enhance protection.Through geometric analysis,it has been confirmed that the deployable multi-layer space shield can occupy less space than conventional space shield structures while expanding into wider shield intervals and multiple layers.Through hypervelocity impact experiments,it was confirmed that as the bumper spacing of the multi-layer space shield expands,its ballistic performance becomes superior to conventional space structures.The deployable multi-layer space shield can reduce not only hypervelocity impacts but also solar radiative heat using the same mechanism as multi-layer insulation.Through cosmic radiation dose analysis,it has been confirmed that the multi-layer space shield is effective in cosmic radiation shielding compared to conventional space structures.展开更多
Composite Thin-walled Lenticular Tube(CTLT)is increasingly utilized in small satellites missions as a lightweight,foldable,and rollable structural material that facilitates the construction of large deployable systems...Composite Thin-walled Lenticular Tube(CTLT)is increasingly utilized in small satellites missions as a lightweight,foldable,and rollable structural material that facilitates the construction of large deployable systems.The CTLT is initially flattened and coiled around a central hub for storage before launch,during which elastic energy is stored as deformation energy,allowing it to be self-deployed on demand for use in orbit.This work presents a comprehensive investigation into the coiling,storage and deployment behaviors of CTLT that wraps around a central hub.A nonlinear explicit dynamic finite element model was developed with both deformable CTLT and rigidbodies mechanisms including the central hub and guide rollers,as well as the complex interactions among them.The coiling mechanics characteristics such as stored strain energy and rotational moment were presented and validated against experimental data in the literature.Then,the dynamic deployment behaviors were analyzed in terms of two different deployment methods,namely,controlled deployment and free deployment.The effect of material property change during storage was also discussed through numerical experiments.展开更多
基金supported by the National Natural Science Foundation,China(Nos.52073224,12472141 and 12002248)the Natural Science Foundation of Shaanxi Province,China(Nos.2023KXJ-034 and 2023KXJ-005)+3 种基金Xi’an Science and Technology Plan Project,China(No.2022JH-ZCZC-0004)the Young Talent Fund of University Association for Science and Technology in Shaanxi,China(No.20210509)the Scientific Research Project of Shaanxi Provincial Education Department,China(No.22JC035)Shaanxi Outstanding Youth Science Fund Project,China(No.2024JC-JCQN-03).
文摘This paper reports the effects of fiber breakage defects and waviness defects on the compressive fatigue behavior and the progressive damage evolution process of 3D Multiaxial Braided Composites (3DMBCs). Combined with finite element compression simulation and ultra-depth microscope, the internal defect content of composites with different braiding angles was determined. The results demonstrate that the weakening effect of waviness and fiber breakage defects is greater than the strengthening effect of the braiding angle. This causes the fatigue resistance of 3DMBCs with the 31° braiding angle being better in both directions of 0° and 90°. The increase of 4° waviness and 10% fiber breakage defect results in the average fatigue life of composites being shortened by 48% and the energy consumption rate increased by 10% at 85% stress level in 90° compression direction. The alteration in loading direction modifies the included angle corresponding to the stress component. The stress component parallel to the fiber direction under compressive fatigue load leads to interfacial debonding in the composites, whereas the stress component perpendicular to the fiber direction results in pronounced shear failure.
基金Supported by the National Research Foundation of South Korea(No.NRF-2021R1A4A1032783)the National Research Foundation of Korea(NRF),the Korea government(MSIT)(No.2022R1C1C1003718).
文摘The multidisciplinary space environment,encompassing orbital debris,cosmic radiation,and solar radiative heat,poses significant risks to spacecraft and astronauts,necessitating efficient and effective shielding solutions.A multi-layer shield with wide spacing has been proven to be an effective way to shield the spacecraft from space debris impact;however,due to the limited volume of the payload fairing,it was not feasible to apply a multi-layer shield to the spacecraft fuselage.Through the origami design,the shield maintains a compact form during launch and subsequently expands in outer space to enhance protection.Through geometric analysis,it has been confirmed that the deployable multi-layer space shield can occupy less space than conventional space shield structures while expanding into wider shield intervals and multiple layers.Through hypervelocity impact experiments,it was confirmed that as the bumper spacing of the multi-layer space shield expands,its ballistic performance becomes superior to conventional space structures.The deployable multi-layer space shield can reduce not only hypervelocity impacts but also solar radiative heat using the same mechanism as multi-layer insulation.Through cosmic radiation dose analysis,it has been confirmed that the multi-layer space shield is effective in cosmic radiation shielding compared to conventional space structures.
基金co-supported by the National Natural Science Foundation of China(No.12202295)the Fundamental Research Funds for the Central Universities,China(No.YJ2021137)+1 种基金the Open Project of State Key Laboratory for Strength and Vibration of Mechanical Structures,Xi’an Jiaotong University,China(No.SV2021-KF-04)the Open Project of State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,China(No.GZ22120)。
文摘Composite Thin-walled Lenticular Tube(CTLT)is increasingly utilized in small satellites missions as a lightweight,foldable,and rollable structural material that facilitates the construction of large deployable systems.The CTLT is initially flattened and coiled around a central hub for storage before launch,during which elastic energy is stored as deformation energy,allowing it to be self-deployed on demand for use in orbit.This work presents a comprehensive investigation into the coiling,storage and deployment behaviors of CTLT that wraps around a central hub.A nonlinear explicit dynamic finite element model was developed with both deformable CTLT and rigidbodies mechanisms including the central hub and guide rollers,as well as the complex interactions among them.The coiling mechanics characteristics such as stored strain energy and rotational moment were presented and validated against experimental data in the literature.Then,the dynamic deployment behaviors were analyzed in terms of two different deployment methods,namely,controlled deployment and free deployment.The effect of material property change during storage was also discussed through numerical experiments.
