boot-heelBNC²³⁶²¹³⁺¹ 例句 In fact, although the single wire of main cables is very soft, when it is bypassesed saddle or boot-heel with a small curvature radius will also give rise to bending stress. 实际上，组成主缆的单根钢丝尽管很柔软，但是当它绕过曲率半径很小的鞍槽或靴跟时也会产生弯曲应力； boshuo