Eeeteng Khoo and Christopher Serratella, of ABS, examine how lifecycle databases can improve structural integrity management.
ABS HM3D is a lifecycle tool that promotes streamlined structural integrity management. Image from ABS.
Challenging operating conditions, increased regulatory demands and the need to preserve asset condition and efficiency lead owners and operators of offshore assets to look for enhanced and cost-effective approaches to structural integrity management (SIM). The industry is shifting from calendar-based intervals toward more condition-based inspection or survey, where inspection, maintenance and repair (IMR) planning is being initiated in the design phase and is revisited and revised based on actual condition data obtained from the asset itself.
A key component of successful SIM is a well-maintained lifecycle database. Ideally, the database is set up with a record of baseline survey measurements and findings, providing the “starting” condition of the asset. Once the asset is in operation, the database is updated after each inspection, survey or repair to reflect the latest condition. This type of continuous condition tracking approach provides a comprehensive understanding of the asset’s health and helps to define future IMR scope and engineering decision-making to prevent escalation in risk and cost.
Answering SIM challenges
Tracking and monitoring asset condition have always been a challenge due to the lack of common practice and experience in storing data and using that data for trending and predictive maintenance. ABS has created two SIM software tools to fill this void. Hull Manager (HM) and Hull Manager 3D (HM3D) are connected via a centralized database to enable fleet-wide trending via data gathered during inspections.
HM is a web-enabled 2D tool for planning, preparing, performing and reviewing inspections that uses a “traffic light” grading system to assess the asset condition and record, track and manage anomalies.
HM3D takes this functionality a step further, recording and displaying structural condition data in a virtual environment that provides the vessel management team with a “digital twin” of the asset that can be used to manage condition data. HM3D is a lifecycle database designed to record condition data from the design stage to the end of service life, using a 3D structural model. The tool allows users to access the history or present condition of a specific structure, compartment or even a complete asset with 3D visualization. It provides an overall view of the structural health of an asset, with graphic filters to focus on condition and inspection findings such as fractures, corrosion levels, deformation and the condition of anodes.
The 3D tool also uses the traffic light grading system on steel structures to identify anomalous locations for IMR work so SIM activities like gauging and repair planning can be planned for optimal execution. For example, areas with substantial corrosion can be identified and assessed to determine if steel replacement is required. An optimal repair can be planned and the associated cost estimated using the software.
In addition, the tool has utility features to support engineering analysis tasks. Because corrosion is heavily dependent on the environment – and its pattern can change over time – a nominal corrosion rate may not be applicable for all the plates and stiffeners. The tool allows the corrosion rate of a specific plate or stiffener to be estimated using recorded gauging values, with options to apply a linear or non-linear trending to predict future wastage.
Geometry models with actual or predicted structural thickness can be extracted and imported into a finite element tool to generate a finite element model (FEM). The main function of this toolkit is to create an FEM with material and thickness properties from a geometry model based on specified requirements via an automated process, which can be used in strength and fatigue assessment and life extension evaluation. This functionality minimizes the FEM creation effort and cost.
Using this tool with the ABS Nautical Systems software enables seamless data-sharing among inspectors and operations and engineering teams, giving all parties real-time access to the latest asset condition, promoting better teamwork and communication, minimizing operation cost, and reducing asset downtime. Finally, lessons-learned can be documented and used as reference for future asset design and SIM programs.
Chris Serratella, director, data management and analytics in the ABS Corporate Technology group, is responsible for guiding ABS research, rule development and industry guidance, specializing in integrity management and methodology and software development related to integrity management. Serratella has worked in the marine and offshore industries for more than 28 years.
Based in Houston, Eeteng Khoo is senior engineer, structures and in-service technology in the ABS Corporate Technology group. Khoo has 10 years of experience in the marine and offshore industries and is responsible at ABS for research, rule development and industry guidance, specializing in structural integrity management and software development related to structural integrity management.