四面体网格划分后，质量有问题

四面体网格划分后，计算应力时，提示有些单元的网格不过关，应该如何改善网格质量呢？红色和蓝色是两个不同的component.初学者求助


Element # 253, element type TETRA.
WARNING - Outside of recommended range: Face Skew Angle = 79.359
upper limit = 75.000
WARNING - Outside of recommended range: Face Vertex Angle = 7.9695
lower limit = 15.000
WARNING - Outside of recommended range: Edge Angle = 80.569
upper limit = 75.000
Element # 263, element type TETRA.
WARNING - Outside of recommended range: Face Skew Angle = 79.359
upper limit = 75.000
WARNING - Outside of recommended range: Face Vertex Angle = 7.9695
lower limit = 15.000
WARNING - Outside of recommended range: Edge Angle = 80.723
upper limit = 75.000