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Damage Probability Analysis of Armor Structure with Multiple Damage Modes under Fragment Penetration

science technology and Engineering 2024年第36期24卷 15447-15456页

作者： Ding, Ming Liu, Yong-Shou Zhang, Yu Bai, Chun-Yu Yang, Qiang Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Aircraft Strength Research Institute of China Xi'an710065 China School of Mechanics and Civil Engineering Northwestern Polytechnical University Xi'an710072 China

The armored structure is exposed to the outside of the target in the combat environment and becomes the primary target of fragmentation. In order to study the multi-mode damage caused by fragmentation, a set of multi-mode damage probability calculation and analysis method was established based on the armored structure penetrated by fragmentation. Based on LS-DYNA simulation calculation, each damage mode was analyzed and the threshold point was determined, and the armor structure damage simulation phase diagram with speed and angle as two-dimensional input variables was drawn. The intersection problem of fragments and armor structure was solved based on the calculation of the intersection point of ray and plane. The solution result was input into the damage simulation phase diagram as input variable, and the output result of the damage simulation phase diagram was used as the criterion of each damage mode. The damage probability of each damage mode under fragment penetration of armor structure was calculated by Monte Carlo method, and the damage probability curve was established. The visual output platform was built and the multi-mode damage cloud image was obtained according to the experimental matrix calculation. The results show that three damage modes, ricochet, penetration and penetration, can be formed when the fragments hit the armor structure at different speeds and angles. The program can calculate the damage probability of each damage mode and output the damage cloud map. © 2024 Beijing Kexue Jishu yu Gongcheng Zazhishe. All rights reserved.

关键词： Monte Carlo methods

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The Experimental and Numerical Study of Aa6061-T6 Aluminum Alloy Under Repeated impacts

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SSRN 2023年

作者： Wang, Binwen Qiu, Zhenguo Gao, Peng Xu, Yuzhao Wang, Changwei Han, Kangning Bai, Chunyu Yang, Qiang Zhu, Yaxin Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Aircraft Strength Research Institute of China Xi’an710065 China Zhuzhou Times New Material Technology Co. Ltd. Zhuzhou412007 China Department of Engineering Mechanics School of Aerospace Engineering Huazhong University of Science and Technology Wuhan430074 China

In this study, we aimed to investigate the effect of repeated impact loading on the fatigue and failure behaviors of U-notched three-point bending AA6061-T6 specimens. After subjecting the specimens to different impact energies, we analyzed the fracture surfaces using SEM. Based on the fracture features, we selected the Gurson-Tvergaard-Needleman (GTN) model as the damage model for AA6061. Then, we established a numerical implementation of impact damage accumulation-based FEM simulation. By calibrating the parameters of the GTN model, we were able to achieve the impact progressions of U-notched three-point bending specimens under repeated impacts. As the repeated impact energy increases, the fracture surfaces transition from visible fatigue striations to abundant ductile microvoids. Comparison between the experimental tests and the numerical simulations of the U-notched three-point bending specimens reveals a high degree of consistency in terms of life and crack propagation for the repeated impacts with high impact energy. This demonstrates the good applicability of the GTN model in capturing the repeated impact behavior of AA6061 under high impact energy. Furthermore, the simulations indicate the specimen's notch experiences tension, compression, and reverse yield processes due to the rebound of the specimen in a single impact, reducing the damage accumulation during repeated impacts. © 2023, The Authors. All rights reserved.

关键词： Aluminum alloys

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Image-Driven Prediction of Fatigue Crack Growth in Metal Materials Via Spatiotemporal Neural Network

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SSRN 2024年

作者： Liang, Jiaming Yu, Yin Hu, Yile Wan, Chunhua Feng, Xiaozhe Lab of Civil Aircraft Structures Testing School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai200240 China Aerospace Structure Research Center School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai200240 China National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of China Xi’an710065 China Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Aircraft Strength Research Institute of China Xi’an710065 China

This study proposes an image-driven model based on SimVP spatiotemporal neural network (STNN) to predict the fatigue crack growth (FCG) in aluminum alloys. This methodology marks a pioneering usage of STNN for FCG analysis. It avoids the need for repetitive modeling, extensive computations, and conventional mechanical assumptions. The datasets are gathered from the fatigue experiments with different crack positions, angles, and load levels, amounting to a total of 17,925 frames of images obtained from DIC. Subsequently, the displacement fields are interpolated onto uniform grids and then augmented to be fitted into STNN. The proposed method is validated with edge- and central-cracked specimens under 15.0% and 20.0% load levels. The generalization performance of the proposed method is studied by predicting FCG under the load levels and crack angles which are absent in the training set. In addition, the predictive capability of FCG is investigated with short and long step-sizes by collecting image data with varying intervals. The over-all structural similarity index measures (SSIM) are above 0.968 and the root mean square error (RMSE) can be suppressed under 0.025 mm. The predicted displacement field, crack length, and crack growth rate have every good agreement with experimental measurements. © 2024, The Authors. All rights reserved.

关键词： Fatigue crack propagation

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impact of Crash Environments on Crashworthiness of Fuselage Section

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Transactions of Nanjing University of Aeronautics and Astronautics 2022年第S01期39卷 1-8页

作者： TANG Huan ZHU Shuhua LIU Xiaochuan XI Xulong College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Aircraft Strength Research Institute of ChinaXi’an 710065P.R.China

In order to study the crash resistance of the civil aircraft structure in different crash environments,two environmental models of soft soil and water are established to analyze the dynamic response of the fuselage section subjected to the vertical at the impact velocity of 7 m/*** results show that the soft crash environment can have a certain cushioning effect on the structure crash,but it will prolong the crash time and change the energy absorption *** work suggests that soft environment may not be suitable for forced landing.

关键词： crashworthiness dynamic response fuselage section soft soil water

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Experimental and Numerical Investigation on Dynamic Shear Behavior of 30CrMnSiNi2A Steel Using Flat-Hat Specimens

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Metals 2025年第5期15卷 563-563页

作者： Xinke Xiao Yuge Wang Shuaitao Wu Chuwei Zhou School of Civil Engineering Nanyang Institute of Technology Nanyang 473004 China Henan International Joint Laboratory of Dynamics of Impact and Disaster of Engineering Structures Nanyang Institute of Technology Nanyang 473004 China School of Architecture and Civil Engineering Harbin University of Science and Technology Harbin 150080 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

An absolutely conflicting value for the incorporation of the Lode parameter into a fracture criterion was reported in the literature when predicting the ballistic resistance of metallic plates failing through shear plugging. In this study, a combined experimental–numerical investigation was conducted to understand the dynamic shear fracture behavior under compression–shear stress states. Flat-hat-shaped specimens of 30CrMnSiNi2A high-strength steel were loaded using a Split Hopkinson Pressure Bar apparatus, combining the ultra-high-speed photography technique, digital image correlation method, and microstructure observation. Parallel finite element simulations were performed using both a modified Johnson–Cook (MJC) fracture criterion or an extended Xue–Wierzbicki (EXW) fracture criterion with Lode dependence to reveal the value of the Lode parameter incorporation. It was found that deformed shear bands with a width of approximately 0.14 mm form at a critical impact velocity. The EXW criterion correctly predicts the critical fracture velocity and estimates the fracture initiation instants within an error of 5.3%, whereas the MJC fracture criterion overestimates the velocity by 14.3%. Detailed analysis shows that the EXW criterion predicts a combined failure mechanism involving ductile fracture and material instability, while the MJC fracture criterion attributes the failure exclusively to material instability. The improved accuracy achieved by employing the Lode-dependent EXW fracture criterion may be attributed to the compression–shear stress state and the accurate prediction of the failure mechanism of the dynamic shear fracture.

关键词： dynamic shear fracture flat-hat specimen digital image correlation Lode-dependent fracture criterion finite element simulation shear localization

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Effect of Temperature on High Strain Rate Tensile Mechanical Properties of Crconi Medium Entropy Alloy

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SSRN 2024年

作者： Wang, Lei Zhao, Xiaohong Zhao, Kaifeng Chen, Zuoming Xi, Yuntao Zhang, Keren Li, Jinguang Xu, Shanna Liu, Haitao Wen, Lei Xiao, Xinke Zhang, Wei Liu, Ruifan Ji, Jiangtao School of Material Science and Engineering Xi'an Shiyou University Xi'An710065 China State Key Laboratory of Rolling and Automation Northeastern University Shenyang110819 China State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing100084 China Nation Center for Materials Service Safety University of Science and Technology Beijing Beijing100083 China Henan International Joint Laboratory of Dynamics of Impact and Disaster of Engineering Structures Nanyang Institute of Technology Nanyang473004 China No. 2 Oil Production Plant of Changqing Oilfield Company Qingcheng745000 China Petroleum Systems Engineering Faculty of Engineering and Applied Science University of Regina ReginaSKS4S 0A2 Canada Northwest Institute for Nonferrous Metal Research Shaanxi Xi'An710016 China Shaanxi Coal Industry New Energy Technology Co. Ltd. Shaanxi Xi'An710199 China China Railway First Survey and Design Institute Group Co. Ltd. Shaanxi Xi'An710043 China

Medium entropy alloys (MEAs) have shown broad application prospects in extreme environmental applications, such as aircraft landing gears and actuators, due to their excellent low-temperature mechanical properties. However, as the temperature rises to room temperature or above, the comprehensive mechanical properties significantly decrease, which has become a bottleneck limiting its application. For this purpose, this work designs gradient twin structures for MEAs and investigates the mechanical response under the combined effects of microstructure design, temperature effects, and strain rate effects from multiple angles. On this basis, combined with the study of tensile mechanical behavior over a wide range of temperature range and different strain rates, the strengthening mechanism of MEAs in gradient twin structures under strain rate temperature coupling conditions is elucidated. The experimental results indicate that: The SPD process has a significant effect on improving the mechanical properties, especially the yield strength, of CrCoNi MEA. The gradient structure enhances the strain rate sensitivity of CrCoNi MEA at room temperature, while reducing its value at high temperatures. For uniform coarse-grained MEAs, an increase in temperature significantly reduces the strain hardening ability, while for gradient structured MEAs, an increase in temperature results in a greater difference in strain hardening ability at different strain rates. © 2024, The Authors. All rights reserved.

关键词： Chromium alloys

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Experimental Study on Hysteresis Characteristics of Fluorosilicone Rubber Damper

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IOP Conference Series: Materials science and Engineering 2020年第1期887卷

作者： Qiang Yang Yunlai Zhou Aircraft strength Research Institute of China Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Xi'an China710065 Faculty of Engineering Lusofona University Campo Grande 376 1749-024 Lisboa Portugal

This study tested the hysteresis characteristics of the damper for determining the damping characteristics. Firstly, dampers with four kinds of hardness, such as 20HA, 30HA, 40HA and 50HA, were obtained by vulcanization. Then hysteresis loops of the dampers were tested by cyclic loading method with displacement of ±0.5mm, ±1.0mm and ±1.2mm. The relationship between stiffness of dampers and hardness was obtained, and it was found that the stiffness of dampers changed quadratically with rubber hardness. The ellipse method is used to calculate the damping factor of the damper. The damping factor of the damper varies with the change of loading displacement and rubber hardness.

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On design of stiffened 3D-multi-cell for enhancing the vehicle crashworthiness and occupant safety 27th

On design of stiffened 3D-multi-cell for enhancing the vehic...

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27th European Safety and Reliability Conference, ESREL 2017

作者： Zahran, M.S. Xue, P. Esa, M.S. Bai, C.Y. Su, G.L. School of Aeronautics Northwestern Polytechnical University Xi’an China Aircraft Strength Research Institute Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics Xi’an China

ISBN: (纸本)9781138629370

State-of-the-art studies of vehicles’ crashworthiness reveal various methods to enhance the crashworthiness characteristics and increase the safety levels. One method that has been studied and applied to achieve the safety of vehicles is using multi-cell thin-walled structures due to their excellent energy absorption capacity with lightweight. Therefore, in the current paper, a new configuration of multi-cell structure (stiffened 3D-multi-cell) has been proposed for designing an efficient energy absorbing structure by performing a new arrangement of the internal webs and dividing them into two layers with a different angle of orientation, and internal lateral bulkhead is added between the upper and the lower layers. The comparison of the crashworthiness characteristics of the newly proposed configuration (stiffened 3D-multi-cell), the single-cell (SCYL), conventional multi-cell (QCYL), and 3D-multi-cell thin-walled circular tube (3D-QCYL) is carried out using the non-linear finite element code ANSYS-WORKBENCH/LS-DYNA. The numerical results show that the newly proposed stiffened 3D-multi-cell can achieve a significant improvement in the absorbed energy, the specific energy absorption, and the crush force efficiency in comparison with model SCYL, model QCYL and model 3D-QCYL. Finally, it can be concluded that reinforcing the 3D-multi-cell with internal lateral bulkhead implies a significant improvement for the crashworthiness. The reason for this improved behavior is the effect of adding the internal lateral bulkhead which increases the stiffness of the crush absorber during the plastic deformation process. © 2017 Taylor & Francis Group, London.

关键词： Crashworthiness

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The experimental study of cotton fiber reinforced ice impact on stringer-stiffed composite panels

The experimental study of cotton fiber reinforced ice impact...

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第三届中国国际复合材料科技大会

作者： Wang Jizhen Aircraft Strength Research Institute of China Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics

To obtain the dynamic behavior and damage properties of simulated hail ice（SHI） impacts on stringer-stiffed composite panels, two aspects of experimental studies were conducted, i.e. SHI impacts tests on the rigid surface and SHI impacts tests on stringer-stiffed panels. SHI impacts on the rigid surface were tested to study the dynamic mechanical properties of clear ice（clear-SHI） and cotton fiber reinforced ice（cotton-SHI）. And the effect of the initial velocity of the SHI to impact load were studied. Then, cotton-SHI impacts on stringer-stiffed panels were tested by different velocity to study the delamination damage property of these panels. According to the C-scan results of the impacted panels, delamination damage with varied shape and size were found for the cotton-SHI impacts, while nearly no damage was found for clearSHI impacts. Especially to deserve to be mentioned, the damage shape and delamination area failed to show a clear law with the increase of the impact velocity.

关键词： simulated hail ice stringer-stiffed composite panels cotton-SHI impact tests delamination damage property

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The experimental study of cotton fiber reinforced ice impact on stringer-stiffed composite panels

The experimental study of cotton fiber reinforced ice impact...

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第二十一届国际复合材料大会

作者： Wang Jizhen Aircraft Strength Research Institute of China Aviation Key Laboratory of Science and Technology on Structures Impact Dynamics

Composite materials have been widely used in the new commercial airliners. During the flight, airliner’s skin may be exposed to hailstone, causing structural damage and destruction, and endangering passengers’safety. Current studies show that nature hail is less dense and tougher than clear ice, and cotton fibers are required to add to the simulated hail ice(SHI) according to

关键词： The experimental study of cotton fiber reinforced ice impact on stringer-stiffed composite panels

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