The Advancements and Applications of Structural Health Monitoring
Maintaining Structural Integrity
The goal of every engineering organization or institution that uses materials, machinery, or structures of any design, is to extend its usage for as long as it is feasible at its full efficiency, with no obstructions. However, the operation of the machinery, loading of a structure, and any mode of utilization of any material will subject it to damage.
Damage is an inevitable consequence of the employment of any subject for its application. Damage is the development of a material, structure, or machine due to utilization that may change a subject's efficiency, structural strength, or performance.
Damage can however be recognized only in a comparative analysis of the state of the structure, material, or machinery from its former or ideal state. This aids in analyzing the changes in properties, geometry, or chemical structure of a subject with a clear point of view.
Non-destructive techniques of analysis of such subjects have proven to be useful in fulfilling these goals, while also maintaining the serviceability of the subject and ensuring its functioning is unhindered or unchanged.
Mankind has utilized multiple methodologies through the ages to check and ensure the quality of the tools and machinery they developed. Hence, the need for the detection of defects, damage, and faults in operation is not novel to mankind’s engineering needs.
Non-destructive testing methods have been sought after in these scenarios, as they reduce waste of resources, time, and probable mishaps. They also help with the premature detection of damage and deformities, enabling industries to perform remedial measures and/or evacuate personnel and valuable machinery from a region of an apparent potential mishap.
Structures that are built to withstand large loads, or to withstand the ill effects of time and that may affect multiple lives and the environment surrounding it, need thorough safety standards and meticulous monitoring for damages and changes to its structural integrity.
The Torre Civica, in Pavia, Italy, is one such example, which was built in the 11th century, and unexpectedly collapsed in 1989 without any prior signs of failure or defects. Such catastrophic failures and the need to evade the losses incurred in such situations created the need for concepts like Structural Health Monitoring in industries.
How Structural Health Monitoring Keeps Your Structures Safe?
Structural Health Monitoring is the method of creating a process to identify flaws and defects in infrastructure, materials, and machinery.
This method is rapidly replacing the standard method of scheduled or sporadic testing and is instead replaced by constant monitoring of structural integrity to prevent failure and rapidly detect failure points.
Structural Health Monitoring uses multiple non-destructive testing and evaluation techniques to gather vital data related to the integrity and performance of a structure, as well as utilizes advanced data management and post-processing techniques to analyze the health, serviceability, and load-bearing ability of a structure.
Structural Health Monitoring is a complex, multi-stage process that involves the monitoring of the structural health of the subject, evaluation of its ability to operate, extraction of vital data that is relevant to the study, and development of models to statistically infer the state of the subject, the trends of the damage within the subject and its operational lifetime.
The concept of structural health monitoring has specific objectives, which include:
- Monitoring the state of an existing subject and looking for methods of enhancing its performance and efficiency from the data obtained.
- Analysis and constant observation of subjects that incur external forces and loads under operation that may translate as vital factors that affect its operation and structural integrity.
- Using data obtained to improve the design of newer versions of the subject or to improve the design of the existing subject.
- To analyze the integrity and strength of structures after the occurrence of natural disasters like tsunamis, earthquakes, etc. which are inevitable and highly catastrophic.
- To enable the increase in the need for maintenance and reworking of existing structures, instead of newer constructions and waste after the failure of structures.
- Transition to a more goal-oriented methodology that assesses a structure or subject based on its performance and criteria that affects it. This helps engineers set performance-based goals during conceptualization so that those factors can be monitored during the operation of the subject and worked with to improve efficiency and performance.
The process of Structural Health Monitoring involves the use of inference techniques like non-destructive testing methods and technologies to observe the subject under study. The process further involves analysis and discovery of the presence of defects and damage, which is followed by a study of the location of the damage in the geometric structure of the subject.
On observing the location of the damage, the system hence studies the subject, and the extent of damage is quantified. The serviceability of the subject is hence determined from the data obtained and the prevailing lifetime of the subject is calculated.
As per research data, Structural Health Monitoring systems are comprised of many elements, that include a low-level identification component that aids in the detection, location, and analysis of faults detected, and a high-level prognostic component that helps in the analysis of test data and assessment of the consequences of the damages present in the subject. (Derriso MM, 2016)
Revolutionizing Structural Health Monitoring for Maximum Safety
Structural Health Monitoring provides an advanced understanding of the structural behavior under operation. It aids in early damage detection and hence reduces the time consumed in inspection and repair processes.
The use of advanced techniques and materials is encouraged by the implementation of structural health monitoring processes. The advent of SHM also encourages the advancement and utilization of improved data handling, structural management, and maintenance concepts.
Visual Inspection Techniques and Non-destructive testing techniques are extensively used in Structural Health Monitoring.
Visual techniques in the process of monitoring the health of a structure can require highly trained inspection personnel and the data obtained can be subjective.
Non-destructive techniques on the other hand utilize multiple technologies in the same procedure. Some processes also require highly trained personnel with experience to operate and infer data from the equipment.
Non-destructive techniques can often also be expensive and time-consuming. Data analysis also requires knowledge of the state of machinery in its ideal state, before testing for damage. Access to the structure is essential for most non-destructive testing processes.
Implementing certain processes may require halting or obstructing the utility of ongoing processes. The Non-destructive testing techniques implemented for structural health monitoring include the following techniques:
- Visual Inspection
- Magnetic Particle Inspection
- Dye Penetrant Testing
- Radiography Testing
- Eddy Current Testing
- Acoustic Emission Testing
- Thermal Infrared Testing
- Ultrasonic Testing
Structural Health Monitoring is of two types, Static Based Structural Health Monitoring and Vibrational Based Structural Health Monitoring. The former method makes inferences based on the assumption that damage to the structure will affect its static properties, whereas the latter works on the assumption that damage will affect the dynamic properties of the structure.
The advent of predictive-modeling techniques, advanced sensors (e.g., smart sensors), developed hardware, and data interrogation software has enabled research and development in the field of structural health monitoring. This allows for the integration of automated assessment systems that work and infer data independently.
Wireless data connections and the use of robots can fully automate structural health monitoring systems and is abundantly available in various forms in the market.
Machine learning has helped shorten the statistical study of data obtained over time and provides pre-set solutions within the system to common issues in the structure.
Artificial intelligence provides numerous solutions to hard computational problems in the monitoring process. This ensures the reliability of the assessment procedure as well as the integrity and load-bearing ability of the structure.
Applications of Structural Health Monitoring
Structural Health Monitoring provides a spectrum of data on the health and operation of a structure. The use of modern technologies and automated systems enables its use for a more diverse set of applications.
Some of the applications of Structural Health Monitoring are:
Monitoring of the stresses incurred by structures under daily load and operation and detection of defects before failure aids in the incorporation of remedial measures and reinforcements to avoid catastrophic losses.
- Highways and roads:
Highways and roads are under the constant harsh impact of natural factors like temperature and rain, Damage due to high-speed vehicles, and excessive loading. Premature analysis of potential failure points may result in quick detection of flaws and save heavier maintenance costs in the long run.
- Bridges and dams:
Bridges and dams are also under constant environmental and loading stresses and require thorough monitoring. Many regions of such structures can be difficult to access, hence it is imperative that advanced systems like SHM are used.
- Protection and maintenance of historical structures:
Ancient structures can be maintained and protected through the years using SHM technologies that help analyze data actively and ensure prompt reworking. Retrofitting of such systems has helped increase the longevity of historically significant structures and preserve mankind’s history.
Challenges and Limitations of Structural Health Monitoring
Structural Health Monitoring requires high-level planning and execution and can provide tremendous benefits in ensuring the reliability of a structure. The challenges faced in implementing Structural Health Monitoring in industries have been extensively documented and researched, some of which are as follows:
- The size and geometries of a subject play an important challenge in the field of Structural Health Monitoring. Vital structures that are larger in size require thorough monitoring of their structure. Apart from providing efficient data, the challenge with such structures is planning and assessing the structural health monitoring technologies to efficiently monitor the subject.
- The appropriate installation and location of the structural health monitoring equipment are extremely complex and vital as it needs to be thoroughly strategized.
- Data acquisition from sensors and diagnostic equipment can also pose a challenge.
- Maintenance of multiple sensors can be complex.
- Access to the structures often proves to be a difficulty as ideal sensor locations can be in inaccessible locations and bad terrain.
- Inevitable natural factors such as high winds, rainfall, and sudden temperature changes may negatively impact the condition of the sensors.
- The diagnosis obtained from Structural Health Monitoring systems must be reliable. The reliability and accuracy of the results should span the operating life of the equipment, else it would create unnecessary and unexpected expenses and losses to the organizations.
- The cost incurred by organizations to implement Structural Health Monitoring must be feasible and should not cost more than the advantages of implementing Structural Health Monitoring systems in the process.
- Meticulous handling of large-scale sensor data is essential from collection to analysis, including careful handling of multiple sensors covering various locations for constant health monitoring of the structure.
Structural Health monitoring utilizes response measurements that are sampled at intervals to assess material and geometric changes to structures under study over a long period. The data is associated with the state of the structure in its ability to operate after incurring damage and change due to external factors like load and environment.
Mankind has utilized variations of structural health monitoring for ages and is still applicable to industries of many kinds. The construction and design of grander, larger structures and machinery and the increased use of alternative energy sources have increased the need for structural health monitoring.
Structural Health Monitoring helps in automating processes and using sensors and other equipment to provide a constant analysis of the structure under study. This aids in implementing large-scale plans in inaccessible regions and harnessing natural forms of energy, which are often processed in regions that are hazardous or inaccessible to humans.
The concept of Structural Health Monitoring is essential to the growth of industries, and efficient processes, as well as enables safety in large-scale structures of importance and further research and implementation will ensure safety, durability, and profit for mankind.