Four-dimensional imaging method for structural damage based on time-invariant characteristic signal

A four-dimensional imaging method for structural damage based on a time-invariant characteristic signal, comprising:

• disposing a piezoelectric sensor network on an aviation structure, wherein the piezoelectric sensor network comprises a plurality of piezoelectric sensors, pitch-catch channels are formed between the piezoelectric sensors, and one pitch-catch channel is formed between each two adjacent piezoelectric sensors;
• constructing a time-invariant characteristic signal of each pitch-catch channel to describe influence on the channel caused by physical damages, wherein the time-invariant characteristic signal is unaffected by time-varying environmental conditions, wherein the time-varying environmental conditions comprise temperature variations, wherein a physical damage is applied to the aviation structure under time-varying environmental conditions;
• imaging the physical damage based on the time-invariant characteristic signals of all the pitch-catch channels in a four-dimensional manner;
• and
• locating the physical damage on the aviation structure according to images resulted from imaging the physical damage in a four-dimensional manner.