Abstract: Repairs of through-wall corrosion damage in pipes conveying liquids using composite sleeves are becoming common in the oil and gas industry. This lecture addresses the repair of through-the-wall corrosion damage in metal pipelines using only bonded patches (metal or composite). The goal is to ensure that the pipe will not leak once the repair is complete. Typically, in practical applications, a composite sleeve combined with a bonded metal patch is used in the repair. It will be shown that a bonded patch (metal or composite) alone can be sufficient to prevent leaking (a composite sleeve is not necessary). In the analysis, metal and composite patches with different thicknesses and roughness were applied to API 5L gr. B steel pipes with 10, 15, and 25 mm holes. The specimens underwent burst hydrostatic tests and the resulting failure pressure values were recorded. Patch thickness, material properties, and surface roughness strongly affect the failure pressure, while pipe diameter has little effect. The results showed that repairs with greater thickness and higher roughness lead to higher failure pressures. A model based on the Linear Elastic Fracture Mechanics is proposed to obtain an estimate of the failure pressure using only one algebraic equation.

Abstract:  Rotating systems represent a class of machines with wide application in the power generation industry. The dynamic analysis of these machines is crucial due to the need to predict operating conditions and ensure their optimal performance. In this context, predictive and preventive maintenance meets the needs imposed by users of rotating machines. In the context of power generation, the demand becomes even more evident and complex due to the great diversity of rotating machines present in this sector. Previous projects focused on the development of rotor analysis software, specifically including parallel shaft transmissions with gears. Therefore, it becomes feasible to analyze the dynamic conditions of more complex rotating machines, such as those using hydraulic speed variators associated with planetary transmissions, allowing the redefinition of safe operating limits in order to mitigate certain critical operating conditions for integrity and investigate new safe set points to protect the system from adverse operating conditions. Thus, through a more comprehensive analysis of these complex systems, a more robust identification process for operating conditions can be established, favoring actions for fault diagnosis and maintenance planning.

Abstract: Damage tolerance (DT) has been successfully applied to aircraft design since the end of the 1970’s. This presentation intends to supply an overview of the state of the art and the future perspectives in DT, related to new aircraft materials (such as composites), novel manufacturing processes and potential maintenance enhancements. Moreover, general aspects of this design philosophy, adding many practical cases, where DT based design solutions and maintenance characteristics significantly improved the level of safety for the airframe, will be presented.

Abstract: The process of implementing a damage detection strategy for aerospace, civil and mechanical engineering infrastructure is referred to as structural health monitoring (SHM). The SHM process compliments traditional nondestructive evaluation by extending these concepts to online, in situ system monitoring on a more global scale. For long term SHM, the output of this process is periodically updated information regarding the ability of the structure to perform its intended function in light of the inevitable aging and degradation resulting from operational environments. After extreme events, such as earthquakes or blast loading, SHM is used for rapid condition screening and aims to provide, in near real time, reliable information regarding the integrity of the structure.
This presentation will briefly summarize the historical developments of SHM technology, which have been primarily driven by four applications: rotating machinery, offshore oil platforms, civil infrastructure, and aerospace structures. Next, the current state of the art is summarized where the SHM problem is described in terms of a statistical pattern recognition paradigm. In this paradigm, the SHM process can be broken down into four parts: (1) Operational Evaluation, (2) Data Acquisition and Cleansing, (3) Feature Extraction and Data Compression, and (4) Statistical Model Development for Feature Discrimination. Examples related to each of these areas will be cited. Next, Outstanding research issues are discussed in the context of this paradigm. This talk will conclude with some final comments on the role of SHM in the goal of providing cradle-to-grave system state awareness, which is a grand challenge for engineers in the 21st century.

Abstract: It is a well know fact that assumptions of classical beam, plate and shell theories often lead to solutions that could deviate significantly from the exact ones. In the recent years, the author and co-workers have successfully introduced and extended the Carrera Unified Formulation, CUF, which is a hierarchical framework to develop any theory of structures for beams, plates and shells including laminated structures and multifield loadings. Equivalent Single Layers, Layer-Wise, Component-Wise, Node-Dependent Kinematics approaches have been successfully applied via CUF to composite structures. Many articles have been extended to various mechanical, thermal and electromechanical problems with excellent and unique accuracy. FEs applications have been developed extensively to both linear and nonlinear problems. The lecture describes the X-DOF method to develop structural theories which can exhibit di ‘any’ X-assumptions for each displacement components (Degree Of Freedom DOF). Applications are given to beams, plates and shells made by metallic and laminated composites. It is concluded that X-DOF combined with NDK provide the most natural way to describe the deformation which is herein denoted as FEM 2.0, that is the next generation Finite Element Method: that is in each point/direction of the structures the FEM 2.o has the most appropriate structural models in the nodes by leading to the most successful and effective method to build the ‘best’ computational model of a given problem related to any structural analysis.

Abstract: Numerous vibration control solutions have been developed in recent years, and are the subject of extensive studies in the literature. These solutions are typically categorized as passive solutions, such as those relying on damping materials or tuned mass dampers, active solutions when integrating sensors and actuators, or adaptive solutions when properties can be adjusted. A major challenge now emerges to design resilient and high-performance vibration control solutions, efficient under highly variable operating conditions while maintaining low maintenance requirements. This presentation details innovative control devices developed to improve robustness and adaptability beyond conventional solutions. The proposed solutions rely on multiple distributed architectures that increase robustness, or on thermo- and magneto-adjustable mechanisms that allow real-time stiffness adaptivity. Experimental and numerical results demonstrate the efficiency of such control strategies under varying vibration levels and operating environments. These developments open up promising prospects for self-adaptive vibration control systems for practical engineering structures.