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HYUNGIL LEE JINYONG CHOI 《Fatigue & Fracture of Engineering Materials & Structures》2004,27(3):245-251
We demonstrate the validity of Je, which comprehensively describes the effects of specimen geometry and loading type, in predicting the fatigue life of auto seat belt anchor panel. We first simplify the heat‐affected zone model to reduce the number of finite elements. We then establish finite‐element models reflecting the actual overload behaviour of three types of seat belt anchor specimens. Using elaborate finite‐element models, we obtain the effective crack‐driving parameter Je composed of its ductility‐dependent modal components. It is confirmed that the Je concept successfully predicts the fatigue life of multi‐spot‐welded panel structures represented by auto seat belt anchors here. 相似文献
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采用微型储能焊机对厚度为 0.2mm 的 0Cr18Ni9 奥氏体不锈钢薄板进行了点焊连接研究,理论分析了微型熔核的温度场和冷却速率.结果表明,微型接头由熔核区和熔合区组成.极短的焊接时间,高的冷却速率 5.1×106 K/s,使得熔核中奥氏体组织来不及长大,熔核凝固组织得到显著细化,具有快速凝固特征;同时,熔核中奥氏体组织在敏化温度区停留时间很短,抑制了铬在奥氏体晶界上的析出.当储能焊接电压为 80V、电容为 6600μF、电极力为 18N 时,可获得综合性能优良的高质量点焊接头.Abstract: The 0Cr18Ni9 austenitic stainless steel sheet with 0.2 mm thickness was welded in capacitor discharge spot welding.The temperature field and cooling rate of nugget was calculated. The results show that the joint microstructure consists of nugget zone and semi-melt zone. Due to very short time in welding, the cooling rate of the joint reaches to 5.1×106 K/s, the growth of austenite microstructure is impeded, and the microstructure of the nugget is refined,which has rapidly solidified characteristics. As the austenite microstructure of the nugget stays in temperature province of activation with very short time, the chrome of austenite grain boundary precipitations is checked. To obtain the high quality spot-weld joint, the welding parameters are determined as: welding voltage 80 V, capacitor 6 600μF and electrode pressure 18 N. 相似文献
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用冷拔钢筋制成的双钢筋混凝土构件和用冷轧带肋钢筋制成的砼构件,均能节约钢材,降低造价,这两种结构已有研究。但用冷轧带肋钢筋制成的双钢筋,目前尚未见研究报道。本文试验研究了冷轧带肋双钢筋砼的受弯构件一梁,结果表明这种构件在承载力和裂缝宽度方面,均具有更好的性能。 相似文献
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低碳汽车薄钢板点焊构件疲劳寿命统计分析 总被引:1,自引:0,他引:1
本文研究了文献的两种点焊工艺条件下的W08A1点焊构件疲劳寿命统计分析,认为焊接电流的变化,对点焊构件中寿命区的疲劳寿命无显著影响,但增大电流,对提高长寿命区的疲劳寿命是有益的。 相似文献
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焊点的疲劳性能是决定车身安全性和可靠性的重要因素. 对不同强度的DP780,DP980和DP1180双相钢焊点进行了检验,在疲劳试验机上进行了拉剪疲劳试验,获得了焊点的疲劳寿命曲线,分析了焊点显微组织、硬度与疲劳性能的关系. 并对焊点的疲劳失效进行了分析. 结果表明:母材性能对其焊点的疲劳性能有较大影响. 母材强度越高即马氏体含量越多,其疲劳性能越优异,三种材料的失效模式均是沿着焊点圆周断裂,裂纹在熔核与母材交界的热影响区萌生,且先贯穿板厚,贯穿板厚的裂纹作为二次裂纹源向板宽方向扩展直至断裂. 相似文献
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垫铁的安装和调整是汽轮机安装中的一项重要工作,其配置是否合理、正确,将直接影响汽轮机的安装质量和精度的高低,甚至影响到汽轮机的使用寿命.结合江铜化工汽轮机垫铁安装过程中遇到的问题,进行了分析,并介绍了几种垫铁施工方法,着重对垫铁配置和安装规范进行阐述. 相似文献
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