ABAQUS为什么提示没定义弹性模量

No bulk modulus is defined for acoustic element 260 instance part-1-1. All acoustic elements must have nonzero bulk modulus defined using *material and *acoustic medium. Initialization of acoustic element material point data for element ... No bulk modulus is defined for acoustic element 260 instance part-1-1. All acoustic elements must have nonzero bulk modulus defined using *material and *acoustic medium. Initialization of acoustic element material point data for element 1 has failed because no bulk modulus exists for thiselement. 其实前面已经定义过弹性模量为210000.泊松比为0.3了，为什么提交作业后还提示这种错误？？？