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Abstract: The main object of this study was to design and implement a suitable algorithm and its simulation for an intelligent traffic signal simulator. The system developed is able to [...]

The article presents the feasibility of a real-time monitoring methodology design and development for early detection of defects in high-temperature pressure components. It indicates the use of a portable acoustic emission (AE) system for emission signals capturing and the statistical analysis (SAS) package for the determination of correlation between the features of such signals. The author concludes the feasibility of using AE for high-temperature pressure vessels monitoring.

This study addressed the critical problem of repairing cracks in aging aircraft structures, a safety concern of paramount importance given the extended service life of modern fleets. Utilized a finite element (FE) method enhanced by the design of experiments (DOE) and adaptive neuro-fuzzy inference system (ANFIS) approaches to analyze the efficacy of piezoelectric actuators in mitigating stress intensity factors (SIF) at crack tips-a novel integration in structural repair strategies. Through simulations, we examined the impact of various factors on the repair process, including the plate, actuator, and adhesive bond size and characteristics. In this work, initially, the SIF estimation used the FE approach at crack tips in aluminum 2024-T3 plate under the uniform uniaxial tensile load. Next, numerous simulations have been performed by changing the parameters and their levels to collect the data information for the analysis of the DOE and ANFIS approach. The FE simulation results have shown that changing the parameters and their levels will result in changing of SIF. Several DOE and ANFIS optimization cases have been performed for the depth analysis of parameters. The current results indicated that optimal placement, size, and voltage applied to the piezoelectric actuators are crucial for maximizing crack repair efficiency, with the ability to significantly reduce the SIF by a quantified percentage under specific conditions. This research surpasses previous efforts by providing a comprehensive parameter optimization of piezoelectric actuator application, offering a methodologically advanced and practically relevant pathway to enhance aircraft structural integrity and maintenance practices. The study innovation lies in its methodological fusion, which holistically examines the parameters influencing SIF reduction in aircraft crack repair, marking a significant leap in applying intelligent materials in aerospace engineering., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests., (© 2024 The Authors.)

Most engineering technologies, gadgets, and systems have been developed around the use of sophisticated materials. Composite laminates have found widespread application in various significant and innovative industries, such as aviation, maritime transportation, automobiles, and civil engineering. Recent studies have revealed that composite materials are extensively utilized in automotive, undersea, and structural applications. Extensive efforts have been dedicated to exploring the structural components constructed from composite materials due to their importance in engineering. While composite materials offer certain advantages over their metallic counterparts, they also present analysts and designers with intricate and challenging issues. Hence, this Review aims to highlight noteworthy studies on composite materials and their engineering applications, specifically focusing on structural components. Furthermore, this Review includes a comprehensive summary of the application of composite laminates, accompanied by a critical analysis of the existing literature in this field. By presenting this information, the Review intends to provide a valuable resource and guideline for researchers interested in leveraging composite materials for engineering structures., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Over the last four decades, numerous studies have been conducted on the use of bonded composite repairs for aircraft structures. These studies have explored the repair of damaged plates through experimental, numerical, and analytical methods and have found that bonded composite repairs are effective in controlling crack damage propagation in thin plates. The use of double-sided composite repairs has been found to improve repair performance within certain limits. This study focuses on these limits and optimizes double-sided composite repairs by varying adhesive bond and composite patch parameters. The optimization process begins with a finite element analysis to determine the stress intensity factor (SIF) for various variables and levels, followed by the application of the Taguchi method to find the optimal combination of parameters for maximizing the normalized SIF. In conclusion, we successfully determined the stress intensity factor (SIF) for various variations and normalized it for optimization. An optimization study was then performed using the Taguchi design and the results were analyzed. Our findings demonstrate the repair performance of bonded composite patches using a cost-effective and energy-efficient approach.

Piezoelectric material transducers can work as an actuator or sensor. Generally, the actuator will be used to repair the structure, and the sensor will be used to find the health condition. In the last two decades, piezoelectric actuators have shown the capacity to lower and control the shear stress concentration and joint edge peel in adhesively bonded joint systems. Hence, this paper aims at reviewing the application of piezoelectric actuators in damaged structures and adhesively bonded combined systems based on three different repair investigation methods: analytical, numerical, and experimental. Moreover, the study also explores the delamination control of composite material beams and some other studies using a piezoelectric actuator. The specific aim of this work is to determine scientific challenges and future opportunities for considering piezoelectric materials in damaged structure investigations for novice researchers., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In aerospace engineering applications, lightweight material structures are considered to perform difficult service conditions and afford energy efficiency. Therefore, composite materials have gained popularity due to their light weights and high performances in structural design. Mechanical loads and environmental conditions primarily create damage to structural materials, thus numerous studies have considered the repair of the damaged structure. Bonded composite repairs are generally chosen, as they provide enhanced stress-transfer mechanisms and joint efficiencies with the increased use of advanced composite materials in primary and secondary aircraft structural components. Thus, it is essential to have reliable and repeatable bonded repair procedures to restore damaged structural components. However, composite bonded repairs, especially with primary structures, present several scientific challenges in the current existing repair technologies. In this review, a study has been done on the bonded composite repair of damaged structures with the stress-intensity factor (SIF) as the parameter for defining the extent of failure by composite repair and unrepaired material structures. In this work, various types of repair methods and the techniques used by researchers are critically reviewed, and future opportunities are explored. The present study was limited to the composite and aluminium materials that are common in aerospace applications.

In the last three decades, smart materials have become popular. The piezoelectric materials have shown key characteristics for engineering applications, such as in sensors and actuators for industrial use. Because of their excellent mechanical-to-electrical and vice versa energy conversion properties, piezoelectric materials with high piezoelectric charge and voltage coefficient have been tested in renewable energy applications. The fundamental component of the energy harvester is the piezoelectric material, which, when subjected to mechanical vibrations or applied stress, induces the displaced ions in the material and results in a net electric charge due to the dipole moment of the unit cell. This phenomenon builds an electric potential across the material. In this review article, a detailed study focused on the piezoelectric energy harvesters (PEH's) is reported. In addition, the fundamental idea about piezoelectric materials, along with their modeling for various applications, are detailed systematically. Then a summary of previous studies based on PEH's other applications is listed, considering the technical aspects and methodologies. A discussion has been provided as a critical review of current challenges in this field. As a result, this review can provide a guideline for the scholars who want to use PEH's for their research.