牙底 meaning in English
root
Examples
- Undercuts for splines - design standard
花键齿的牙底削平.设计标准 - Undercuts and runouts for screw threads - specification for iso metric screw threads
螺纹牙底削平和收尾规范.第2部分: iso米制螺纹规范 - The fatigue fracture occurred in the root of the screw where defects such as decarburization and cracks existed , and these defects made the zone to be a stress concentration area and caused the bolts to break finally
疲劳裂纹的形成是由于螺纹牙底存在脱碳和折叠裂纹等缺陷，这些缺陷的存在使该材料产生了较大的应力集中，从而导致螺栓开裂失效。