共查询到20条相似文献,搜索用时 31 毫秒
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为获得复合材料作为风扇包容机匣时遭受叶片冲击载荷时的动态响应、损伤与失效模式,在空气炮装置上使用叶片形弹体对Kevlar织物层合板开展了弹道冲击试验,结果发现:复合材料靶板厚度提高25%,复合材料靶板吸收的能量提高约92%;随着叶片弹体速度的增加,复合材料靶板的损伤破坏逐渐严重,从轻微的压痕,转变为横向和纵向裂纹与分层损伤,再转变为矩形穿孔,同时靶板背面出现纤维断裂、纤维拔出与分层失效等现象;在叶片弹体撞击下,靶板上在与弹体接触的局部区域形成鼓胀变形,并在弹体击穿或反弹后发生变形回复;叶片弹体的横滚角将导致叶片的作用范围增大,使得靶板抗冲击性能有所提高。 相似文献
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为保障飞行安全,航空发动机机匣需具有足够的抗冲击能力以包容高速旋转状态下丢失的叶片。针对某型涡扇发动机对开式风扇机匣包容性评估需求,提出了1种结合真实机匣打靶试验和有限元分析评估机匣包容能力的方法。通过使用真实机匣和真实叶片进行打靶试验获得风扇机匣的冲击损伤情况,并基于ANSYS/LS-DYNA进行了瞬态动力学有限元分析。结果表明:采用Johnson-Cook模型预测的机匣伤形状、尺寸以及叶片残余速度均与试验结果接近,验证了数值分析方法的准确性。采用验证过的数值分析方法开展旋转状态下机匣的包容性评估,发现由于撞击姿态差异和失效模式转变,风扇机匣可以包容以100%工作转速飞出的叶片,但机匣出现长裂纹,接近临界包容状态。所提出的方法可以在不具备部件包容试验条件的情况下,以较方便的形式对机匣包容能力可靠评估。 相似文献
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为研究航空发动机双层结构金属机匣在受叶片冲击时的包容性问题,利用滑膛炮试验系统对双层钛合金带不同间隙叠层靶板进行打靶弹道试验。通过28次有效的弹道试验发现:对比内层(迎弹面)、外层靶板厚度相同带间隙组合的试验结果,间隙越大靶板抗侵彻能力越差;对比不带间隙组合试验结果,内层较薄组合的抗侵彻能力强于内、外层厚度相同组合。采用商业有限元软件ANSYS/LS-DYNA对打靶试验进行了数值仿真,有限元仿真与试验结果吻合较好,并发现内层较薄组合的抗侵彻能力强于内层较厚组合,且两者均强于内、外层厚度相同组合;各个组合在没有间隙的情况下,弹道极限随叶片攻角增加而增加,但是速度曲线突增的攻角有所不同。无量纲靶厚决定了叶片冲击双层靶板的破坏模式。 相似文献
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为研究机匣抵抗轮盘碎片撞击的能力和破坏方式,找到机匣结构优化设计的方法.用显式非线性动力学软件Dytran计算1/3轮盘碎片与单层和双层靶板的撞击过程.碎片及靶板均选用Johnson-Cook材料本构模型,结合Gruneisen状态方程.撞击过程基于Lagrange算法采用显式有限元计算.结果发现,靶板主要破坏方式为整体塑性变形、剪切撕裂和拉伸断裂;间距较大时双层靶板的弹道极限速度随间距的增加而增大;前靶板厚度比例较小或较大时弹道极限速度较大;单层靶板的抗击穿能力优于厚度均布的双层靶板.因此,通过对双层靶板的厚度和间距进行合理的搭配,能达到比同等厚度的单层靶板更好的抗击穿性能. 相似文献
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为了考察混杂纤维复合材料层板的抗弹冲击性能,采用碳纤维织物或玻璃纤维织物与芳纶纤维织物复合材料层共固化的方式,利用热压罐成型工艺制备了几种具有不同面密度及铺层结构的混杂纤维复合材料层板,并进行抗弹冲击性能测试、表观形貌观察和无损检测分析。结果表明:纯芳纶纤维及混杂纤维复合材料层板的钢弹冲击破坏模式相同,均为表层剪切破坏,中间层分层破坏,背层拉伸断裂破坏;层间混杂顺序对复合材料层板的分层缺陷面积有较大影响,当碳纤维层作为背层时,层板的分层缺陷面积为12 863. 6 mm2小于玻璃纤维层作为背层时(17 400. 5 mm2);当芳纶层作为背板时,混杂纤维复合材料层板冲击后分层缺陷面积与纯芳纶的相当(14 151. 0~14 927. 0 mm2)。混杂纤维复合材料对层板的抗弹冲击性能有较大影响,混杂后复合材料的弹道极限速度(v50)均有一定程度的提高,其中玻璃纤维/芳纶复合材料的v50从纯芳纶复合材料层板的193. 08提高至204. 33 m/s。将碳纤维层或玻璃纤维层作为着弹面层的混杂纤维复合材料层板具有更优异的抗弹冲击性能,其贯穿比吸能(BPI)均优于纯芳纶复合材料层板。 相似文献
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Study on ballistic penetration resistance of titanium alloy TC4, Part II: Numerical analysis 总被引:1,自引:1,他引:0
Enhancing containment capability and reducing weight are always great concerns in the design of casings. Ballistic tests can help to mitigate a catastrophic event after a blade out, yet taking time and costing money. A wise way is to hunt for a validated numerical simulation technology, through which the material dynamic behavior over the strain rate range in the ballistic tests should be represented and reasonable failure strain should be defined. The simulation results show that the validation of the numerical simulation technology based on the test data can accurately estimate the absorption energy, describe the physical process and failure mode during the penetration, as well as the failure mechanism. It is found that energy dissipation of projectiles is in manner of compression stage, energy conversion stage, and interactive scrap stage. An effect indicator is proposed, where the factors of critical velocity including impact orientation and mass of projectiles and thickness of casings are considered. The critical velocity presents a linear relation with the effect indicator, which implies the critical velocity obtained by the flat casing could underestimate the capability of the real casing. 相似文献
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《中国航空学报》2021,34(12):125-144
In this paper, a failure evaluation criterion was proposed for the bolted casing-flange structure under impact loading. Subsequently, ballistic tests with eighteen bolted casing-flange structure specimens were conducted to validate the failure evaluation criterion. Parameter studies were then carried out using the validated FE models. Both the experimental and numerical results demonstrated the accuracy of the failure evaluation criterion. The failure evaluation criterion provided a quick and easy way to determine the failure mode of the casing connection area by using the materials and dimensions of the structure. Based on the failure evaluation criterion, designing the structural failure mode of the bolted casing-flange structure to be between flange failure and bolt failure can improve the impact resistance of the connection area of the aero-engine casings. This investigation revealed that the impact failure is not the unique criterion in evaluating the containment of the casing connection area, structural failure should also be involved in the evaluation criteria. 相似文献
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Influence of pre-tension on ballistic impact performance of multi-layer Kevlar 49 woven fabrics for gas turbine engine containment systems 总被引:1,自引:0,他引:1
In this paper, ballistic impact tests on wrapped multi-layer Kevlar 49 woven fabric systems were carried out with a flat blade projectile to investigate the impact response during a fan blade out event. The influences of the number of Kevlar layers and pre-tension were discussed particularly. Test results were used to analyze failure modes and energy absorption characteristics of multi-ply Kevlar fabrics. Results show that there are two kinds of impact damage for fabrics: global deformation mainly involving stretching of yarns in the impact region and fabric wrinkle from both sides to the impact zone, and local damage characterized by yarn fracture, yarn pull-out, and yarn unraveling. The energy absorption capability of Kevlar 49 woven fabrics improves with the number of fabric layers. The energy absorbed by multi-layer fabrics increases slightly at the beginning and then decreases substantially with pre-tension. The work in this paper can provide guidance for designing light-weight multi-layer fabrics containment systems. 相似文献
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钢球对肥皂靶的撞击试验 总被引:1,自引:0,他引:1
为研究投射物对生物体的致伤效应,采用肥皂作为生物体模拟物,开展了Φ3.0mm 的钢球高速(0.96和1.88km/s)及超高速(3.52和4.98km/s)撞击肥皂靶的试验,获得了肥皂靶在钢球撞击下的损伤特征及其破坏规律。结果表明:高速试验条件下,钢球对肥皂靶的损伤主要表现为贯穿效果;超高速试验条件下,钢球撞击肥皂靶形成大尺寸半球形弹坑,其对肥皂靶的损伤表现为2个方面:一是大尺寸弹坑导致的“体积移除”,二是受超高速撞击的强烈冲击波影响,肥皂靶的破坏区域大于弹坑区域。 相似文献
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针对发动机工作时受预载荷的叶片受到外物冲击的情况,设计一种面内单轴及双轴预加载装置,开展单轴与双轴不同大小预拉载荷下碳纤维/环氧树脂复合材料(T700/TDE-86)的高速冲击试验,探究预拉载荷对复合材料抗冲击性能的影响,并结合超声C扫描分析预拉载荷对损伤面积的影响。结果表明:面内初始载荷对复合材料层合板抗冲击性能和分层损伤面积有显著影响;预拉载荷会提高靶板的抗弯刚度,减少靶板吸收的能量,减小弹道极限,且在双轴预拉情况下更明显;弹体击穿靶板后分层损伤面积几乎不变,而预拉载荷会减小分层损伤面积,且在双轴预拉情况下更明显。 相似文献
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本文在片光遮挡式弹丸探测技术基础上发展了光电阵列探测亚毫米级弹丸技术,论述了光电阵列探测亚毫米弹丸的技术原理,详细介绍了光电阵列探测系统的探测光路和探测电路设计方案,研制了光电阵列探测系统的动态试验验证装置。在超高速碰撞靶上开展了动态验证试验,试验结果表明,采用光电阵列探测技术,大幅提高了弹丸信号的信噪比,能够可靠探测直径为0.6mm 的高速弹丸,通过分析表明该技术能可靠应用于直径为0.1mm高速弹丸的探测。 相似文献
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提出了一种由金字塔型点阵金属骨架、陶瓷棒、环氧树脂胶结剂、金属面板及背板所组成的复合材料结构模型。基于有限元法,在实验验证数值方法有效性的基础上,模拟研究了该型复合结构对三类钢制弹丸(平头、球头和锥头)的抗侵彻机制。对比分析了弹靶模型各子结构的失效模式、吸能效率、弹丸的塑性变形、弹道特性、速度及加速度等变化规律。结果表明:弹头形态对复合靶板的破坏形态和吸能特性有较大影响,平头弹丸和球头弹丸对靶板主要产生冲塞破坏,达到峰值加速度的时间较短;而锥头弹丸主要表现为刺穿扩孔型破坏,达到峰值加速度的时间较长,侵彻效能最高。在弹体高速侵彻靶板的过程中,由于金属骨架的剪切扩孔和塑性变形、陶瓷棒的断裂破坏以及金属面板与背板的塑性变形,使得该型防护结构的抗侵彻能力得到了显著提高。 相似文献
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Tracking of a Ballistic Missile with A-Priori Information 总被引:2,自引:0,他引:2
Benavoij A. Chisci L. Farina A. 《IEEE transactions on aerospace and electronic systems》2007,43(3):1000-1016
The paper addresses the problem of estimating the launch and impact points of a ballistic target from radar measurements. The problem has been faced under different hypotheses on the available prior knowledge. The proposed approach combines a nonlinear batch estimator with a recursive MM (multiple model) particle filter in order to attain the estimation goal. Extensive simulations assess the achievable estimation performance. 相似文献
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在不增加空间碎片防护结构整体尺寸和质量的情况下,基于防护结构在斜撞击条件下弹道极限高于正撞击条件下弹道极限的特性,研究了一种将3层平行铝板结构的中间层进行倾斜的N 型防护结构,采用超高速碰撞试验和三维SP H 数值仿真方法,定量对比了N型防护结构与相同面密度3层平行铝板结构的防护性能。研究结果初步证实,在正撞击情况下,倾斜的中间层具有提升结构防护性能的作用。 相似文献
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Ballistic impact tests were carried out with examined projectiles of the Ti-6Al-4V titanium alloy to investigate the impact response of the 2618 aluminum plates at a nominal velocity of 210 m/s. The influence of projectile forms and oblique angles on damage formation was particularly discussed by applying different loading conditions such as multiple projectile forms and oblique angles. Additionally, the numerical simulation method was employed to provide further insight into the characteristics of damage and target responses. The Johnson-Cook(J-C)constitutive model with revised failure parameters was used to support the simulations to assess target responses and characteristics of the damage created from different impact conditions. Results show that there is a significant transition in the deformation mode as changes of the projectile form are applied. Moreover, the cracks on the back of the 2618 aluminum alloy plates impacted by the solid plate projectile and the hollow blade projectile tend to locate at different positions, which are supposed to be influenced by local bending and stretching. The work in this paper may provide guidance for the design of fan blade containment systems. 相似文献