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...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.展开更多
离岸围网设施通常布置在开阔水域,受波流作用影响显著。为确保围网结构的安全,需对其水动力特性开展研究。为此,以一种浮绳式围网为研究对象,通过拖曳水池试验对围网整体阻力性能进行分析。根据有限单元法建立波浪作用下围网结构受力的...离岸围网设施通常布置在开阔水域,受波流作用影响显著。为确保围网结构的安全,需对其水动力特性开展研究。为此,以一种浮绳式围网为研究对象,通过拖曳水池试验对围网整体阻力性能进行分析。根据有限单元法建立波浪作用下围网结构受力的数学模型,通过计算机数值模拟对围网浮子的最大位移与网衣张力进行研究。结果显示:随着流速的增大,围网整体阻力逐渐增加,阻力与流速呈幂函数关系,阻力最大值为196 k N。当浮绳式围网在波浪作用下,上纲中迎浪面中点处浮子的位移最大,位移值为80 mm,网片与锚绳连接点及下纲四角连接处的网线张力较大。建议适当增加迎流面网衣所配备的浮力,以使围网在较高流速时保持形状。此外,在实物网衣的制作中,锚绳与下纲四角连接处的网衣应做加固处理。展开更多
基金co-supported by the National Natural Science Foundation of China (No.51575262)the China Postdoctoral Science Foundation (No.2015M571754)the Aeronautical Science Foundation of China (No.2015ZB52008)
文摘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.
文摘离岸围网设施通常布置在开阔水域,受波流作用影响显著。为确保围网结构的安全,需对其水动力特性开展研究。为此,以一种浮绳式围网为研究对象,通过拖曳水池试验对围网整体阻力性能进行分析。根据有限单元法建立波浪作用下围网结构受力的数学模型,通过计算机数值模拟对围网浮子的最大位移与网衣张力进行研究。结果显示:随着流速的增大,围网整体阻力逐渐增加,阻力与流速呈幂函数关系,阻力最大值为196 k N。当浮绳式围网在波浪作用下,上纲中迎浪面中点处浮子的位移最大,位移值为80 mm,网片与锚绳连接点及下纲四角连接处的网线张力较大。建议适当增加迎流面网衣所配备的浮力,以使围网在较高流速时保持形状。此外,在实物网衣的制作中,锚绳与下纲四角连接处的网衣应做加固处理。
