Dynamic loading failure experiment of aeronautic rivet
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摘要: 为研究航空铆钉连接元件在动态加载下的失效模式,依托高速液压伺服材料试验机,通过特殊设计的实验夹具,进行了6类航空铆钉在不同加载速度和不同加载模式下的动态失效实验,获得了铆钉元件在纯拉伸加载、纯剪切加载、30°拉-剪耦合加载和60°拉-剪耦合加载状态下的失效实验数据。实验结果表明,铆钉元件的失效模式和失效载荷与加载速度、载荷的作用形式密切相关,并基于实验结果拟合得到铆钉元件的失效本构参数,获得了可表征铆钉在一般情形下失效的本构方程。Abstract: To obtain the failure modes of aeronautical rivets under dynamic loading, dynamic failure experiments were carried out for six aeronautical rivets at different speeds and in different loading conditions on a high-speed servo hydraulic test machine using clamps specially designed, and the experiment data were achieved concerning the failure modes of the rivets working under pure tension, pure-shear, 30° combined tension-shear and 60° combined tension-shear. The results showed that the failure modes and the failure load of the rivets were closely related with the loading speed and the loading conditions. The failure constitutive parameters were obtained by fitting the experiment results, the failure constitutive equations of the rivets in the general case were also derived.
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Key words:
- dynamic failure /
- high-speed servo hydraulic test machine /
- rivet /
- constitutive equation
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表 1 铆钉的类型和几何尺寸
Table 1. Type and dimension of rivets
铆钉 d/mm l/mm 类型 系列 3.97 7.94 100°精密沉头 A 3.97 7.94 平圆头 B 3.97 7.94 100°剪切沉头 C 4.76 7.94 平圆头 D 4.76 7.94 100°剪切沉头 E 3.18 7.94 100°剪切沉头 F 表 2 铆钉元件动态失效载荷和加载速度的关系
Table 2. Relationship between rivet failure load and loading velocity
系列 关系式 A F=0.53lnv+4.38 B F=0.61lnv+4.63 C F=0.69lnv+4.41 D F=1.16lnv+6.30 E F=1.05lnv+6.20 F F=0.71lnv+3.30 注:F的单位为kN, v的单位为m/s。 表 3 6类铆钉的失效模式和位置
Table 3. Failure modes and positions of six styles of rivets
系列 类型 失效模式和位置 纯拉 30°拉-剪 60°拉-剪 纯剪 A 沉头 沉头拉脱 墩头拉脱 钉杆拉-剪 钉杆剪断 B 半圆头 墩头拉脱 墩头拉脱 钉杆拉-剪 钉杆剪断 C 沉头 沉头拉脱 沉头拉脱 钉杆拉-剪 钉杆剪断 D 半圆头 墩头拉脱 墩头拉脱 钉杆拉-剪 墩头处剪断 E 沉头 墩头拉脱 沉头拉脱/墩头拉脱 钉杆拉-剪 墩头处剪断 F 沉头 沉头拉脱 沉头拉脱 钉杆拉-剪 钉杆剪断 表 4 铆钉的失效本构参数
Table 4. Failure constitutive parameters of six styles of rivets
系列 Nu/kN Tu/kN a b 本构关系 A 3.93 2.93 3.28 1.94 ${{\left( \frac{N\left( a \right)}{3.93} \right)}^{3.28}}+{{\left( \frac{T\left( a \right)}{2.93} \right)}^{1.94}}\ge 1 $ B 4.32 3.26 1.32 1.88 $ {{\left( \frac{N\left( a \right)}{4.32} \right)}^{1.32}}+{{\left( \frac{T\left( a \right)}{3.26} \right)}^{1.88}}\ge 1$ C 3.29 3.31 2.02 2.16 ${{\left( \frac{N\left( a \right)}{3.29} \right)}^{2.02}}+{{\left( \frac{T\left( a \right)}{3.31} \right)}^{2.16}}\ge 1 $ D 5.24 4.52 2.36 1.92 $ {{\left( \frac{N\left( a \right)}{5.24} \right)}^{2.36}}+{{\left( \frac{T\left( a \right)}{4.52} \right)}^{1.92}}\ge 1$ 注:N(a)、T(a)的单位为kN。 -
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