Structural Health Monitoring - the process of monitoring and assessing the state or condition of a structure system.  Structural Health Management - the process of making appropriate decisions/recommendations about mission and maintenance actions based on structural health assessment data using built-in expert system and artificial intelligent tools.

A key to enabling management as opposed to simple monitoring is prognosis: predicting what will happen to the structure as a result of its condition (such as a damaged state)  

• Information technology is the key to prognosis for structures.
• computers, software, and electronic sensors

SHM Technology Growth or Maturation

• DC-XA, a vertical take-off and vertical landing Reusable Launch Vehicle (RLV)
• Flight experiment included fiber optic and acoustic emission (AE) sensor systems.
• 16 optical fiber sensors (12 strain and 4 temperature) and 32 other conventional strain (foil strain gage) and temperature (RTD) sensors monitored LH2, LOX and intertank structures.
• 4 Acoustic Emission (AE) sensors monitored the Y-joint of the LH2 tank.
• Successfully demonstrated fiber optic sensors for measuring temperature and strain, and AE Flight Instrumentation System performance, in the extreme environment during the rocket powered flight.
• Data helped demonstration of 8 hours turn around operations. <

Figure 2. SHM technology was demonstrated during DC-XA experimental flights, including (a) an acoustic emission flight instrumentation system, (b) sensors bonded on the composite LH2 tank, and (c) a fiber optic sensing system.

Real-time Structural Health Monitoring Using Acoustic Emission

Damped repair design procedure

• Repair high-cycle fatigue cracks in aircraft secondary structure
• Damage Dosimeter for quick characterization of dynamic strain and temperature environments
• Flight demonstrated on B-52, F-15, and C-130

 Payoff for Air Force

• Decreased aircraft maintenance costs, extended service life, and increased aircraft availability

Current Applications In Boeing: Commercial airplane SHM development

Objective:

Develop Structural Health Monitoring (SHM) techniques and system that would detect impact damage, bondline failures and cracks in primary and secondary structures of future high-speed vehicles such as Space Operating Vehicles (SOV) and Future Strike Aircraft (FSA).

Motivation

• Inspections are required for bonded repairs.
• Sensors may help mitigate disassembly and inspection costs.

Project Flow

• Develop requirements.
• Select sensor technologies.
• Coupon testing.
• Algorithm development. <
• Component testing.
• Implementation readiness.

• Potential Applications for Commercial Airplane
• Conclusion: 2020 Vision for SHM