| According to existing research,in the design of flexible bioinspired armor structures,the main task is to find a balance between flexibility,impact resistance and behind armor blunt trauma.Nowadays,the research based on bioinspired armor structure design still has limitations in revealing the impact resistance response mechanism.At the same time,due to the extremely complex tissue structure of the human body,it is very different from the imitated creatures.When the bioinspired protective equipment is worn on the human body,whether it can coordinate with the human body and whether it can achieve the maximum protective effect still needs further research.In the face of complex world situation,improving individual combat protection capabilities is not only of extraordinary scientific research significance,but also of extraordinary mission value to the country and nation.This paper intends to carry out research on the structural design and impact resistance mechanism of flexible bioinspired protective armor.By learning from the common impact protection principle of scale armor and subcutaneous fat of natural organisms,the flexible bioinspired protective armor structure is designed.The experimental research and the simulation work are carried out to discuss the impact resistance mechanical response and energy absorption behavior of the equivalent flexible bioinspired protective armor.Combined with typical and effective experimental data and numerical models,an analysis method is extracted and a research route is summarized,which ultimately provides reference and guidance for the replacement design and preparation of wearable flexible protective equipment.The main research contents are as follows:(1)From the perspective of bionic generalization,according to the distribution of bone plates in the armadillo shell,an equivalent bioinspired protective structure for armadillo skin—the bioinspired segmented scale armor was designed.The impact resistance performance of the armor under the simulated human body support was studied through the drop weight impact experiment and numerical simulation,and the synergistic effect of each component in the impact resistance process of the bioinspired segmented scale armor was revealed.By decoupling the material strength by numerical simulation method,the optimal impact resistance response mode and the optimal material strength range of the bioinspired segmented scale armor are obtained.When the strength of the scale material is reduced to 1/50 of the original strength,the total energy absorption of the scale structure is increased by 273%.Through reasonable material selection and structural design,the impact response of the body armor can be made closer to the ideal mode,which can greatly improve the structural efficiency of the body armor.This part of the research can provide references for armor configuration improvement and front plate design.(2)According to the synergistic impact resistance mechanism,the high efficiency impact resistance response mode and the optimal material method obtained in the study of the bioinspired segmented scale armor,and referring to the sandwich structure of the armadillo osteoderm,an improved bioinspired protective structure—a bioinspired multi-cell armor with viscous fluid was designed.Through the drop weight impact experiment,the impact resistance response performance,the interaction mechanism between the layers and the energy absorption behavior of the bioinspired multi-cell armor with viscous fluid under the behavior of low velocity impact are discussed.Studies have demonstrated that the energy absorption capacity of the front plate layer has been improved,and the viscous fluid filling layer can strengthen the synergy of the armor.The full-stage impact bending stiffness of the bioinspired multi-cell armor is increased by 16.8%,which can reduce the maximum intrusion displacement by 8.3%.At the same time,increasing the initial contact efficiency is one way to improve the armor’s energy absorption ability.Under the dynamic impact load,the response of the body armor under the simulated human support condition displays strong nonlinearity.After the load peak caused by the initial contact,the typical equivalent bioinspired protective structure has a weakening period in the process of being compacted by the impact load,while the multi-cell armor structure can maintain a high level of resistance in this stage,with higher energy absorption efficiency and protection ability.These results means that the structural form of multi-cell armor can provide a reference and basic support for the design of higher-level flexible bioinspired protective armor.(3)Based on the research results of the bioinspired segmented scale armor and the bioinspired multi-cell armor,an ideal armor prototype – the bioinspired hierarchical flexible filled armor was designed,and the low velocity resistance and ballistic performance of the armor was tested under the condition of simulated human support.Studies have shown that the armor has better low velocity resistance and ballistic performance than the soft body armor specimen on the basis of ensuring better flexibility.Compared with the soft body armor specimen,the depth of the after-effect dent is reduced by 16.5% under low speed impact test,and the after-effect dent depth is reduced by about 6% in the ballistic impact test.In addition,the design of the multi-cell front layer also guarantees its multiple impact resistance ability.A two-factor normalized evaluation method was established to normalize the experimental results using areal density and structure thickness to evaluate the mass efficiency and space efficiency of armor.Combined with the three methods of experimental test,numerical simulation and theoretical analysis,the response mechanism of the bioinspired hierarchical flexible filled armor against bullet impact is analyzed,and its protective effect and efficiency against bullet impact at each component are revealed.(4)The anti-penetration performance of high-speed fragments simulating projectiles and the ballistic limit V50 of the bioinspired hierarchical flexible filled armor were studied.Based on the V50 velocity results,the two-factor normalized evaluation method was used to evaluate the energy absorption efficiency of the ballistic limit condition.Compared with typical soft body armor specimen,the mass energy absorption efficiency of the bioinspired hierarchical flexible filled armor is increased by 9%,and its space energy absorption efficiency is increased by 125%.The bioinspired hierarchical flexible filled armor not only has the advantages of high thickness energy absorption efficiency of the metal panel armor structure,but also is slightly better than the typical fiber bulletproof structure.It is a body armor design with better comprehensive performance.On the basis of the experimental test results,the research mode of mutual complementation and verification between the experiment-simulation-theoretical analyses is perfected,the performance of the structure is intuitively evaluated through the experimental test,and the experimental results provide the basis for the establishment and verification of the numerical model.Combined with experimental observation,numerical simulation and theoretical analysis,the mechanism of armor’s resistance to high-speed fragments simulating projectiles is studied,and the characteristics of energy absorption behavior and damage distribution are combined to deconstruct the role and material efficiency of each level of armor in the impact resistance process.This research preliminarily verifies the effectiveness and application value of the bioinspired hierarchical flexible filled armor against threats at different speeds. |
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