The larger the structure can tolerate the amount of uncertainty, the more reliable, vice versa.It can be described as the partial order relation between the hype-rectangles in mathematics.

• 结构所能承受的不确定度越大就越可靠，反之就不可靠，在数学模型上表现为激振力频率区间集与结构固有频率区间集的偏序关系。