The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making co...The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.展开更多
This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinf...This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinforced Plastics(CFRP).Different surface conditions were created by these treatments and simple Resin Pre-Coating(RPC)technique was further used to reduce the potential void defects at the root of those micro-cavities.Carbon Nanotubes(CNTs)were guided into the etched micro-cavities to construct quasi-Z-directional fiber bridging and form the“CNT-reinforced epoxy-pins”.The surface performance testing results imply that anodic oxidation of Al substrate created relatively even and continuous channels with higher hardness and better wettability among these treatments,which could provide quasi-vertical spaces for containing epoxy adhesive or CNTs.The single lap shear test results show combined treatments of anodic oxidation and upgraded RPC with CNTs technique on Al substrate yielded the highest bonding strength of 21.8 MPa(up to 243.3% greater than base strength).The constructed through-the-thickness“epoxy-pins”or“CNT-reinforced epoxy-pins”contributed to failure modes changing from complete debonding failure of Al substrate to peeled-off shallow fiber or delamination failure of CFRP panel.The combined treatments could be utilized to manufacture high-performance Al-CFRP composites for aviation industry application.展开更多
Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical s...Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical stabilities.This study utilised NaOH anodising method to create micro-rough titanium surfaces for enhancing adhesive bonding between titanium alloy and CFRP laminates.A special and simple technique named Resin Pre-Coating(RPC)was also employed to improve the surface wetting of anodised titanium and grinded CFRP substrates.The influences of anodising temperature and duration on the surface morphology,wettability and adhesive bond strength were investigated.The single lap shear test results showed that the bond strength of specimens anodised at 20℃for 15 min improved by 135.9%and 95.4%,respectively,in comparison with that of acid pickled and grinded specimens(without RPC treatment).Although increasing the anodising temperature and duration produced rougher titanium surfaces,the adhesively bonded joints were not strong enough due to relatively friable titanium oxide layers.展开更多
全髋关节置换术(total hip arthroplasty,THA)术后可能会出现感染、深静脉血栓(deep vein thrombosis,DVT)、关节不稳定、脑梗死等并发症,其中脑梗死并发症在THA围手术期具有发病率低但病死率高、病理因素复杂及发病隐匿等特点。根据LA...全髋关节置换术(total hip arthroplasty,THA)术后可能会出现感染、深静脉血栓(deep vein thrombosis,DVT)、关节不稳定、脑梗死等并发症,其中脑梗死并发症在THA围手术期具有发病率低但病死率高、病理因素复杂及发病隐匿等特点。根据LANES等[1]研究发现,THA术后缺血性脑梗死发生率为1.9%,但随着社会老龄化加剧以及老年患者抗应变能力差、骨质疏松等原因,髋骨骨折发病率正不断升高,THA围手术期脑梗死的发生率也随之增高,其危害不容小觑。展开更多
The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transitio...The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.展开更多
The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fi...The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.展开更多
基金co-supported by the Foundation of Shanghai Astronautics Science and Technology Innovation,China(No.SAST2022-114)the National Natural Science Foundation of China(No.62303378),the National Natural Science Foundation of China(Nos.124B2031,12202281)the Foundation of China National Key Laboratory of Science and Technology on Test Physics&Numerical Mathematics,China(No.08-YY-2023-R11)。
文摘The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.
基金supported financially by the National Natural Science Foundations of China(No.52102115)the Natural Science Foundation of Sichuan Province,China(No.2025HJRC0019)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)。
文摘This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinforced Plastics(CFRP).Different surface conditions were created by these treatments and simple Resin Pre-Coating(RPC)technique was further used to reduce the potential void defects at the root of those micro-cavities.Carbon Nanotubes(CNTs)were guided into the etched micro-cavities to construct quasi-Z-directional fiber bridging and form the“CNT-reinforced epoxy-pins”.The surface performance testing results imply that anodic oxidation of Al substrate created relatively even and continuous channels with higher hardness and better wettability among these treatments,which could provide quasi-vertical spaces for containing epoxy adhesive or CNTs.The single lap shear test results show combined treatments of anodic oxidation and upgraded RPC with CNTs technique on Al substrate yielded the highest bonding strength of 21.8 MPa(up to 243.3% greater than base strength).The constructed through-the-thickness“epoxy-pins”or“CNT-reinforced epoxy-pins”contributed to failure modes changing from complete debonding failure of Al substrate to peeled-off shallow fiber or delamination failure of CFRP panel.The combined treatments could be utilized to manufacture high-performance Al-CFRP composites for aviation industry application.
基金supported by the National Natural Science Foundations of China(No.52102115)the Natural Science Foundations of Sichuan Province,China(No.2023NSFSC0961)the Fundamental Research Funds of Jiangsu University of Science and Technology,China(No.1022932318)。
文摘Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical stabilities.This study utilised NaOH anodising method to create micro-rough titanium surfaces for enhancing adhesive bonding between titanium alloy and CFRP laminates.A special and simple technique named Resin Pre-Coating(RPC)was also employed to improve the surface wetting of anodised titanium and grinded CFRP substrates.The influences of anodising temperature and duration on the surface morphology,wettability and adhesive bond strength were investigated.The single lap shear test results showed that the bond strength of specimens anodised at 20℃for 15 min improved by 135.9%and 95.4%,respectively,in comparison with that of acid pickled and grinded specimens(without RPC treatment).Although increasing the anodising temperature and duration produced rougher titanium surfaces,the adhesively bonded joints were not strong enough due to relatively friable titanium oxide layers.
文摘全髋关节置换术(total hip arthroplasty,THA)术后可能会出现感染、深静脉血栓(deep vein thrombosis,DVT)、关节不稳定、脑梗死等并发症,其中脑梗死并发症在THA围手术期具有发病率低但病死率高、病理因素复杂及发病隐匿等特点。根据LANES等[1]研究发现,THA术后缺血性脑梗死发生率为1.9%,但随着社会老龄化加剧以及老年患者抗应变能力差、骨质疏松等原因,髋骨骨折发病率正不断升高,THA围手术期脑梗死的发生率也随之增高,其危害不容小觑。
基金supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06).
文摘The high-performance Basalt Fiber Reinforced Polymer(BFRP)composites have been prepared by guiding Micro/Nano Short Aramid Fiber(MNSAF)into the interlayer to improve the resin-rich region and the interfacial transition region,and the flexible fiber bridging claws of MNSAF were constructed to grasp the adjacent layers for stronger interlaminar bond.The lowvelocity impact results show that the MNSAF could improve the impact resistance of BFRP composites.The compression test results demonstrate that the compressive strength and the residual compressive strength after impact of MNSAF-reinforced BFRP composites were greater than those of unreinforced one,exhibiting the greatest 56.2% and 73.3% increments respectively for BFRP composites improved by 4wt%MNSAF.X-ray micro-computed tomography scanning results indicate that the“fiber bridging claws”contributed to better mechanical interlocking to inhibit the crack generation and propagation under impact and compression load,and the original delamination-dominated failure of unreinforced BFRP composites was altered into sheardominated failure of MNSAF-reinforced BFRP composites.Overall,the MNSAF interleaving might be an effective method in manufacturing high-performance laminated fiber in industrial production.
基金Supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+2 种基金the Natural Science Foundation of Sichuan Province,China(No.2023NSFSC0961)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)the Postgraduate Innovation Fund Project by Southwest University of Science and Technology,China(No.24ycx2027).
文摘The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.
