(西北工业大学 凝固技术国家重点实验室, 西安 710072)
摘 要: 在电磁约束成形中通过Aφ-A三维有限元法所得的磁感应强度、 涡流密度和集肤层厚度分布,求得电磁压力的分布; 对具有不同宽厚比的带圆角矩形截面样件所受的电磁压力进行了分析。 发现宽厚比越大的样件, 相邻两边电磁压力之差也越大。 圆角形状产生的涡流流向变化也能明显改变样件表面电磁压力的分布,当圆角半径接近或小于集肤层厚度时, 角部与直边连接处形成一个电磁压力衰减区, 这种电磁压力分布规律极大地增加了大宽厚比小的圆角矩形样件截面的成形难度。
关键字: 电磁约束成形; 电磁场; 电磁压力; 数值模拟
( State Key Laboratory of Solidification Processing, Northwestern Polytechnical University,
Xi’an 710072, China)
Abstract: The distribution of electromagnetic pressures is computed on magnetic induction intensity, eddy density, and skin depth, which are calculated by Aφ-A of 3-D FEM in electromagnetic confinement and shaping. The pressures on round-rectangle samples with different width-thickness ratio are analyzed. The higher the width-thickness ratio is, the higher the electromagnetic pressure differential between broad edge and narrow edge is. The direction change of eddy current coming from the angle structure changes the distribution of electromagnetic pressure. When the radius of round angle is close or little than skin depth, the electromagnetic pressure between the round angle and the straight edge will be attenuated. This distribution of electromagnetic pressure makes shaping the section with large width-thickness ratio and little round angle more difficult.
Key words: electromagnetic shaping; electromagnetic field; magnetic pressure; digital simulation