Radial & Tangential Stress (glossary)
径向与切向应力分布（术语）
标签：应力, 径向, 切向, 开裂, 原理
下凹时金属中心受双向拉伸：径向应力沿半径向外，切向应力沿圆周方向。越靠边缘切向拉伸越大，故边缘最易开裂或起波浪。理解此分布可指导：下凹深度与料径比例控制在约 0.3 以内、边缘多退火，以平衡两向应力避免失稳起皱。
In sinking the centre is in biaxial tension: radial stress acts outward along the radius, tangential stress around the circumference. Tangential tension grows toward the rim, so the edge cracks or waves first. This guides practice: keep depth-to-diameter ratio under ~0.3 and anneal the rim often to balance the two stresses and avoid buckling. ---