Contact characteristic analysis of bolted joint on machine tools considering temperature effect
-
摘要: 螺栓连接结构广泛应用于机械装备之中,其特性对整体结构的力学性能有显著影响。由于螺栓杆及连接构件热伸缩系数上的差异,温度变化导致的螺栓杆及连接件的热变形会使得螺栓的预紧力发生变化,从而影响整体结构的动力学特性。文章基于有限元分析研究温度对螺栓连接结构接触特性的影响,并以机床中常用的铸铁材料为例,依次研究了连接板厚、螺栓直径、螺栓预紧力与温度耦合情况下的接触特性,并采用克里金插值法构建了螺栓接触特性参数库。结果表明:当连接板的厚度较小时,温度变化对接触特性影响并不显著,当板厚增大到一定程度后,温度变化会使接触区域的变化及接触应力的变化显著增大;预紧力较小时,温度变化影响接触区域大小和平均接触应力,预紧力增大到一定程度后,温度变化对接触特性的影响不明显。Abstract: Bolt connection is widely used in mechanical equipment and has a significant effect on the mechanical properties of the whole structure. Due to the difference in thermal expansion coefficient of bolt rod and the connect structures, the thermal deformation of bolt rod and connect structures caused by temperature change will change the bolt preload, thus affecting the contact characteristics of the contact surface and the dynamic characteristics of the whole structure. This paper studied the influence of temperature on the contact characteristics of bolted structures based on finite element analysis. The iron material which widely used in machine tools is taken as an example and the contact characteristics of connecting plate thickness, bolt diameter, bolt preload coupling with temperature are studied. The contact characteristics parameter database of bolts was constructed by Kriging interpolation method. The results show that when the thickness of the connecting plate is small, the influence of temperature change on the contact characteristics is not significant. While the change of the contact area and contact pressure will be significantly increased by temperature change when the thickness of the connecting plate increases to a certain value. The temperature change will affect the size of contact area and the average contact pressure when the preload is small, while this influence is not obvious when the preload increases to a certain value.
-
Key words:
- bolt joint /
- contact analysis /
- temperature influence /
- contact pressure /
- contact radius
-
表 1 温度对接触特性的影响分析
温差/℃ 0 10 20 30 应力/MPa 1.86 1.98 2.12 2.29 应力变化/(%) / 6.4 13.9 23.1 半径/mm 65.1 63.1 60 56.8 半径变化/(%) / −3.4 −8.1 −13 表 2 不同板厚的接触特性(温差30 ℃)
板厚/mm 10 20 30 40 应力值变化/MPa 0.49 0.1 0.43 0.54 应力值变化/(%) 4.43 1.07 23.12 35.29 半径值变化/mm 0.63 0.9 8.5 14.71 半径值变化/(%) −2.29 −1.97 −13.02 −20.46 表 3 不同预紧力时的接触特性(温差30 ℃)
预紧力/N 12 500 25 000 37 500 50 000 应力值变化/MPa 0.34 0.43 0.43 0.32 应力值变化/(%) 31.31 23.12 15.86 8.86 半径值变化/mm 11.5 8.5 6.4 4.3 半径值变化/(%) −18.23 −13.02 −9.65 −6.49 表 4 不同连接工况下的平均接触应力
连接工况 温差/℃ 0 5 10 15 20 25 30 B10F12500 5.53 5.53 5.53 5.53 5.53 5.53 5.53 B10F25000 11.1 11.1 10.6 10.6 10.6 10.6 10.6 B10F37500 15.3 15.7 15.7 15.7 15.7 15.7 15.7 B10F50000 21.1 20.9 19.8 18.8 18.6 18.9 18.8 B20F12500 1.94 1.93 1.93 1.92 1.91 1.92 1.91 B20F25000 3.73 3.65 3.78 3.71 3.65 3.7 3.69 B20F37500 5.38 5.37 5.58 5.49 5.41 5.42 5.62 B20F50000 7.45 7.38 7.45 7.21 7.26 7.44 7.25 B30F12500 0.99 1.02 1.11 1.19 1.21 1.27 1.3 B30F25000 1.86 1.92 1.98 2.08 2.12 2.24 2.29 B30F37500 2.71 2.82 2.78 2.89 3 3.16 3.14 B30F50000 3.62 3.54 3.66 3.65 3.74 3.84 3.94 B40F12500 0.82 0.9 1.01 1.08 1.12 1.16 1.21 B40F25000 1.53 1.54 1.73 1.82 1.91 2.03 2.07 B40F37500 2.21 2.24 2.36 2.53 2.66 2.75 2.98 B40F50000 2.86 2.92 2.97 3.15 3.35 3.59 3.51 表 5 不同连接工况下的平均接触半径
连接工况 温差/℃ 0 5 10 15 20 25 30 B10F12500 27.5 27.5 27.5 27.5 27.5 27.5 27.5 B10F25000 27.5 27.5 28.1 28.1 28.1 28.1 28.1 B10F37500 28.1 28.1 28.1 28.1 28.1 28.1 28.1 B10F50000 28.1 28.1 28.1 28.1 28.1 28.1 28.1 B20F12500 45.4 45.4 45.4 45.4 45.4 45.4 45.4 B20F25000 46.3 46.3 46.3 46.3 46.3 46.3 46.3 B20F37500 47.2 47.2 46.3 47.2 47.2 47.2 46.3 B20F50000 46.3 47.2 48.1 45.4 49 47.3 49 B30F12500 63.1 62.1 58.9 55.8 54.7 52.6 51.6 B30F25000 65.3 64.2 63.1 61 60 57.9 56.8 B30F37500 66.3 63.1 65.2 63.1 61.3 58.9 59.9 B30F50000 66.3 66.3 65.2 65.2 64.2 63.1 62 B40F12500 69.2 65.2 59.8 55.8 53.1 50.4 47.8 B40F25000 71.9 71.9 66.5 63.8 61.2 58.5 57.1 B40F37500 73.2 73.2 70.5 67.9 65.2 61.2 62.5 B40F50000 74.5 74.5 73.2 71.9 67.9 67.9 65.2 -
[1] Yoshimura M. Making use of CAD technology based on the dynamic characteristics data of joints to improve the structural rigidity of machine tools[J]. Machine Tools, 1979, 1(1): 142-146. [2] 伍良生, 马淑慧, 屈重年, 等. 弹簧-阻尼动力学单元螺栓连接结合面研究[J]. 机械设计与制造, 2014(1): 4-6. doi: 10.3969/j.issn.1001-3997.2014.01.002 [3] 刘晓峰, 孙伟, 方自文. 基于非均匀分布复弹簧单元的螺栓连接薄板结构动力学有限元建模[J]. 振动与冲击, 2021, 40(13): 111-119. doi: 10.13465/j.cnki.jvs.2021.13.015 [4] 孙志勇, 孙伟, 孙清超, 等. 螺栓连接结合部薄层单元参数优化辨识[J]. 机械设计与制造, 2019(1): 50-54. doi: 10.3969/j.issn.1001-3997.2019.01.014 [5] 史文博, 杜静, 龚国伟. 风电机组轮毂螺栓连接建模与接触强度分析[J]. 机械设计与制造, 2019(12): 169-172. doi: 10.3969/j.issn.1001-3997.2019.12.042 [6] Tian H, Li B, Liu H, et al. A new method of virtual material hypothesis-based dynamic modeling on fixed joint interface in machine tools[J]. International Journal of Machine Tools and Manufacture, 2011, 51(3): 239-249. doi: 10.1016/j.ijmachtools.2010.11.004 [7] 毛宽民, 黄小磊, 李斌, 等. 一种机床固定结合部的动力学参数化建模方法[J]. 华中科技大学学报:自然科学版, 2012, 40(4): 49-53. [8] 毛宽民, 李斌, 雷声. 机床结合部动力学建模及应用[M]. 武汉: 武汉理工大学出版社, 2018: 148-179. [9] 王棒, 李亦军, 王高, 等. 发动机燃烧室出口温度分布测试的新型传感器[J]. 中国测试, 2019, 45(8): 112-117. doi: 10.11857/j.issn.1674-5124.2019020054 [10] 武斌, 蔡存朋, 曹正林, 等. 增压发动机排气管前端法兰结合面高温密封问题研究[J]. 汽车工艺与材料, 2021(10): 7-11. doi: 10.19710/J.cnki.1003-8817.20200497