Modelling and Numerical Simulations of In-Air Reverberation Images for Fault Detection in Medical Ultrasonic Transducers: A Feasibility Study

Table 4

Defect simulations: values of reduced Young’s modulus for different transducer layers.

Damage severity; (or damage case)	Backing layer damage	Matching layer damage	Lens layer damage	Crystal layer damage
	Young’s modulus Pa	Young’s modulus Pa	Young’s modulus Pa	Stiffness denominator
1	1 · 10	1 · 10	1 · 10^3	1000
2	1 · 10^3	1 · 10^3	1 · 10^5	100
3	1 · 10^5	1 · 10^5	1 · 10^7	10
4	1 · 10^7	1 · 10^7	1 · 10^8	4
5	1 · 10^9	1 · 10^9	5 · 10^8	2
6	3 · 10^9	3 · 10^9	1 · 10^9	1.7
7	6 · 10^9	6 · 10^9	2 · 10^9	1.4
8	9 · 10^9	9 · 10^9	3 · 10^9	1.2