Structural health monitoring (SHM) systems for hydrogen transport tanks are critical for ensuring safety, reliability, and compliance with industry standards such as ASME BPVC Section XII. Wireless SHM technologies offer advantages in real-time monitoring without the need for extensive wiring, making them particularly suitable for mobile hydrogen transport applications. Three key technologies in this domain are acoustic emission sensors, strain gauge arrays, and battery-less near-field communication (NFC) tags. Each plays a distinct role in detecting structural anomalies, measuring mechanical stress, and enabling passive data retrieval.
Acoustic emission sensors are widely used for detecting active defects such as cracks, leaks, or material fatigue in hydrogen transport tanks. These sensors capture high-frequency stress waves generated by sudden energy releases within the tank material. In hydrogen transport, where tanks are subjected to cyclic loading and potential embrittlement, acoustic emission monitoring provides early warning of structural degradation. The sensors are typically piezoelectric and can be mounted externally to avoid compromising tank integrity. Data is transmitted wirelessly to a central processing unit where algorithms analyze signal characteristics like amplitude, duration, and frequency to identify defect types and locations. ASME BPVC Section XII mandates periodic inspection of transport tanks, and continuous acoustic emission monitoring can supplement these requirements by providing real-time data between formal inspections.
Strain gauge arrays are another essential component of wireless SHM systems for hydrogen transport tanks. These arrays consist of multiple strain sensors distributed across high-stress regions to measure deformation caused by internal pressure, mechanical loads, or thermal fluctuations. Traditional foil strain gauges are often replaced with fiber Bragg grating (FBG) sensors in wireless systems due to their immunity to electromagnetic interference and multiplexing capability. FBG sensors reflect specific wavelengths of light that shift in response to strain, allowing precise measurements without electrical connections. The data from these sensors is transmitted via wireless nodes to a monitoring system that evaluates stress distribution and identifies potential overloading conditions. Compliance with ASME BPVC Section XII requires that tanks maintain structural integrity under specified pressure limits, and strain gauge arrays provide direct verification of these conditions during operation.
Battery-less NFC tags represent an emerging solution for passive SHM in hydrogen transport tanks. These tags harvest energy from external readers via inductive coupling, eliminating the need for onboard power sources. NFC tags can be embedded with sensors to measure parameters such as temperature, pressure, or residual gas concentrations. When a reader is brought within proximity, the tag transmits stored data, enabling maintenance personnel to perform quick inspections without disassembling the tank. This technology is particularly useful for tracking long-term degradation trends and verifying tank conditions before and after transport cycles. While NFC tags do not provide real-time monitoring like acoustic emission sensors or strain gauge arrays, they offer a low-cost, maintenance-free alternative for periodic checks. ASME BPVC Section XII does not explicitly mandate wireless monitoring, but the use of NFC tags aligns with the standard’s emphasis on regular inspection and documentation of tank conditions.
Integration of these wireless SHM technologies into hydrogen transport systems requires careful consideration of environmental factors. Hydrogen tanks are often exposed to extreme temperatures, vibrations, and potential impacts during transit, necessitating robust sensor designs. Wireless communication must also account for signal interference from metal tank structures and other transport equipment. Encryption and error-checking protocols are essential to ensure data integrity, particularly when monitoring safety-critical parameters.
ASME BPVC Section XII provides guidelines for the design, fabrication, and inspection of hydrogen transport tanks but does not prescribe specific SHM methods. However, the standard’s focus on leak prevention, pressure containment, and material compatibility underscores the importance of continuous monitoring. Wireless SHM systems can help meet these objectives by detecting defects before they escalate into failures. For example, acoustic emission sensors can identify microcracks that might lead to hydrogen leakage, while strain gauge arrays ensure tanks remain within safe stress limits during filling and transport.
The adoption of wireless SHM in hydrogen transport is still evolving, with ongoing research aimed at improving sensor accuracy, energy efficiency, and data processing capabilities. Future developments may include hybrid systems combining multiple sensing technologies for comprehensive monitoring. As hydrogen becomes a more prominent energy carrier, the role of wireless SHM in ensuring safe and efficient transport will continue to grow.
In summary, wireless structural health monitoring systems for hydrogen transport tanks leverage acoustic emission sensors, strain gauge arrays, and battery-less NFC tags to enhance safety and compliance with ASME BPVC Section XII. These technologies enable real-time defect detection, stress measurement, and passive data retrieval without the limitations of wired systems. By integrating these solutions, operators can improve the reliability of hydrogen transport while meeting regulatory requirements.