『求助』一个很简单的热传导问题！求教各位高人！

小弟是abaqus的初级用户，一个简单的热传导问题想请教各位高人！问题很简单 一个四方形板 上端加温度100 一个侧面和底面加温度0 ， 算的结果出现警告：There is zero HEAT FLUX everywhere in the model based on the default criterion. please check the value of the average HEAT FLUX during the current iteration to verify that the HEAT FLUX is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero HEAT FLUX.
请问高人 是何问题！拜谢！！！！