Shear Behavior of Self Drilling Screws Used in Low Ductility Steel
Shear Behavior of Self Drilling Screws Used in Low Ductility Steel
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低延展性钢用自钻螺钉的剪切性能
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
R. A. Laboube
中科院分区：
文献类型：
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作者：
Randy L. Daudet;R. A. Laboube
本文介绍了264根自钻螺钉的剪切试验结果。进行的测试包括单螺钉单剪切、双螺钉单剪切和单螺钉双剪切。将低延性钢中自钻螺钉的性能和行为与普通延性钢中螺钉的性能和行为进行比较。将结果与1986年AISI规范（含1989年附录）和最近批准的AISI自钻螺钉规范（将纳入下一版AISI规范）进行比较。此外，提出了新的方程的倾斜/轴承的极限状态的螺钉在单剪切，和轴承的极限状态的螺钉在双剪切。简介在今天的轻型钢结构中，主要的紧固方式是通过使用自钻螺钉。大多数自钻螺钉的直径范围为0.16英寸。0.25 in.长度范围为0.625英寸。到2.0英寸。这种螺钉具有基本上是钻头的尖端，其作用是在螺纹接合第一钢层之前钻穿所有钢连接件的孔。完全预钻孔可确保在螺钉完全就位后，钢连接层被紧紧夹紧。由于第一层不能在第二层或第三层之前爬上螺钉的螺纹，因此确保了夹紧。自钻螺钉可用于连接总厚度为0.5英寸的钢板。1993年2月6日，AISI规范委员会批准了自钻螺钉的设计规定（1），该规定将纳入下一版AISI规范（2）。尽管新的设计规定将被证明对设计者非常有用，但它们未能解决低延性钢中使用的自攻螺钉的设计问题。因此，需要做更多的工作，以更好地了解在不同延展性的钢中使用的自钻螺钉。本文将总结一项关于在低韧性钢中使用自钻螺钉的综合研究的结果和结论（3）。该研究解决了几个不同的主题，涉及到使用自钻螺钉在低延性钢，包括：-低延性钢与正常延性钢的螺钉行为; -单剪和双剪螺钉; -连接能力时，负载施加垂直或平行于冷轧方向; -螺钉容量与钻尖类型; -使用多个紧固件; -与AISI的比较。本文主要讨论了单剪时的倾斜/承载极限状态和双剪时的承载极限状态。试验计划为了基本了解单枚螺钉在单次剪切中的行为，对图1中的配置A和B进行了试验。对图1中的测试装置C和D进行测试，以研究多个螺钉在低延展性钢中的行为是否与在正常延展性钢中的行为不同。测试配置E以确定螺钉在双剪切中的行为。对于所有测试的配置，钢带为1-7/8”宽和12”长。螺钉边缘距离和间距是AISI推荐的螺钉直径的三倍，以防止紧固件边缘撕裂。所有螺钉都足够长，因此一旦螺钉完全就位，至少3个螺钉螺纹可见。1升。兰迪·都德体育迪特里希工业，哈蒙德，印第安纳州。2 RA LaBoube，Ph.D，P.E.，密苏里大学罗拉分校，罗拉，密苏里州。
The results of 264 shear tests conducted on self drilling screws are presented. The tests conducted include single screws in single shear, two screws in single shear, and single screws in double shear. The performance and behavior of self drilling screws in low ductility steel are compared to the performance and behavior of screws in normal ductility steel. Results are compared to the 1986 AISI specification with 1989 addenda, and the recently approved AISI specification for self drilling screws which will be included in the next edition of the AISI code. Also, new equations are presented for the tilting/bearing limit state for screws in single shear, and the bearing limit state for screws in double shear. Introduction In light gage steel construction today, the predominant means of fastening is through the use of self drilling screws. Most self drilling screws are produced in diameters ranging from 0.16 in. to 0.25 in. and in lengths ranging from 0.625 in. to 2.0 in. Such screws have tips that are essentially drill bits which function to drill a hole through all of the connecting pieces of steel before the screw threads engage the first steel layer. The fully pre-drilled hole ensures that the connecting layers of steel are tightly clamped once the screw is fully seated. Clamping is ensured due to the fact that the first layer cannot climb the threads of the screw in advance of the second or third layers. Self drilling screws can be used to connect steel sheets that have a total thickness of 0.5 in. On February 6,1993 the AISI SpeCification Committee approved design provisions (1) for self drilling screws which will be incorporated into the next edition of the AISI Specification (2). Although the new design provisions will prove to be very useful for deSigners, they fail to address the design of self tapping screws used in low ductility steel. Therefore, more work is required to obtain a better understanding of self drilling screws used in steels with various degrees of ductility. This paper will summarize the results and conclusions of a comprehensive study concerning the use of self drilling screws used in low ductility steel (3). The study addressed several different topics related to the use of self drilling screws used in low ductility steel including: -screw behavior in low ductility steel versus normal ductility steel; -screws in single and double shear; -connection capacity when load is applied either perpendicular or parallel to the direction of cold reduction; -screw capacity versus drill tip type; -the use of multiple fasteners; -comparison with AISI. This paper will mainly address the tilting/bearing limit state for screws in single shear, and the bearing limit state for screws in double shear. Test Plan In order to achieve a basic understanding of how a single screw behaves in single shear, configurations A and B in Figure 1 were tested. Test setups C and D in Figure 1 were tested to investigate if multiple screws behave differently in low ductility steel than they do in normal ductility steel. Configuration E was tested to ascertain the behavior of screws in double shear. For all tested configurations, steel strips were 1-7/8" wide and 12" long. Screw edge distance and spacing was three times the screw diameter as recommended by AISI to prevent edge tear out of the fasteners. All screws were long enough so that at least 3 screw threads were visable once the screw was fully seated. 1 L. Randy Daudet, P.E., Dietrich Industries, Hammond, Indiana. 2 RA LaBoube, Ph.D, P.E., University of Missouri-Rolla, Rolla, Missouri.