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With the application of composites driven by an industry need to replace conventional materials, products must be designed to a lightweight criterion with safety margins essential to guarantee consumer safety. Non-destructive testing is used to ensure that safety and confirm that a component is fit for purpose. To improve inspection processes, the...
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... Compared with their metallic counterparts, composite laminates possess unique characteristics and demonstrate complex fracture and fatigue behavior. For several decades, NDE methods were broadly used for inspecting thin composite laminates [1,[3][4][5][6][7][8][9][10]. However, introducing thick laminated structures, mainly in marine applications, created new challenges in NDE. ...
... The primary components of a metamaterial are unit cells at sub-wavelength scales that make it possible to consider an AMM to be a continuum medium [3]. Based on their extraordinary properties, AMMs found many applications in acoustic engineering, such as superlens [4], acoustic cloaking [5], waveguiding [6], wave filtration [7], wave amplification, and wave enhancement [8]. ...
Significant challenges exist in inspecting thick composite laminates for manufacturing defects and operational damage. This is due to acoustic attenuation and impedance mismatch at the interface between the different composite layers. An innovative concept for enhancing ultrasonic testing of such composite laminates is introduced in this study. The proposed solution exploits the ability of acoustic metamaterials to cloak virgin composite. Herein, we show that by incorporating carefully designed metamaterials in a pulse-echo ultrasonic testing setup, the position and size of a delamination in a thick hybrid composite laminate can be determined accurately.
There are many types of the non-destructive test (NDT) method and in this regard ultrasonic testing is the most common method used in composite inspection. The main purpose of the inspection is to detect the defect that occurs in the composite such as cracks, delamination, void, and others. The common Ultrasonic NDT equipment is quite large, expensive and the system is also complex. This research is conducted to develop a small scale of NDT machine with a simple system having an ability to operate immersion ultrasonic testing of the composite and obtain enhanced results compared to conventional product design. The water is used as a coupling medium for the sound beam to travel between the transducer and specimen. The new design of water tank is also developed to make this product become more ergonomic. This small-scale machine has an ability to operate in two axis which is x and y axis and there was a stepper motor used on the axis which was controlled using Arduino Genuino Mega 2560 and Adafruit Motor Shield v2 as a microcontroller and a motor driver respectively. In the inspection process, a transducer of Harisonic Ultrasonic from Olympus corporation with a frequency of 2.25 MHz was used with a pulser-receiver. The result of the specimen such as the location and size of a crack were obtained from the generated signal. The sample of the specimen tested was fiber glass composite laminates (FGCL) with holes as an artificial defect. The suitable stepping mode of the stepper motor with the least vibration produced during operation was analyzed. The structural analysis of the proposed design was done using simulation in Solidwork software. Motion study was used to analyze the basic hand, arm, and body movements of users as they used the machine. It was found that the newly developed NDT machine produced less vibration due to the enhanced mechanical design and stepping motor configuration, and it was found to be more ergonomic compared to previous scanning unit product design.KeywordsNon-destructive testingComposite inspectionUltrasonic testingVibrationErgonomic
Received Signal Strength is the measure of attenuation of electromagnetic signals emitted by the access point, reaching the receiver after traveling some distance. This work used the attenuation of Wireless Local Area Network signals propagated through the air for the purpose of indoor positioning. Previous research had shown some problems such as indoor mapping requires human effort and are time-consuming. Furthermore, received signal strength for different indoor conditions may vary such that constant calibration and new acquisition for unknown indoor locations is required. An approach to reduce manual acquisition is by employing prediction algorithms. In this work, an analysis on prediction techniques used predict the RSS is analyzed in the context on indoor positioning. First, to determine the optimum training size for the models, the models are given different training size. Then the models are evaluated based on the similarity of signal pattern predicted and the error between the predicted signal and real signal. In conclusion, the random function model showed best estimation for signal for most of the tested signal received at certain distances from the transmitter. The optimum training size found for all the prediction models are 1100 out of 1200 data. It is also found that for a very noisy data set, the minimum training size for best result are at 900 out of 1200. Bayesian Support Vector Regression outperforms other models in terms of root mean square error.KeywordsIndoor positioningFingerprintReceived Signal StrengthWLAN
Electric vehicle being one of the leading green technologies nowadays,
is leaving a humongous amount of spent lithium-ion batteries untreated. Current research on lithium-ion battery waste management is at its minimal because the huge power range of the battery is much attractive than the battery waste dismantling process. Treating these battery wastes are crucial for rare metal recovery due to its
limited resources on land. Thus, this study aims to propose an eco-design battery pack to ease the recycling process in a more economical and sustainable manner. SolidWorks is used to generate the 3D modelling and ANSYS is utilized to carry out the simulation of the product’s mechanical performance in a drop and impact tests.
Results shows that the proposed design of EV battery pack has a design efficiency of one with Easy Fixings indicator of 28%. In the drop test of 0.3 m height, it yields a maximum deformation of 1.015e−3m and a generated Von-Mises stress of 4.827e 8N/m2. Other than that, 2.5227e6 N/m2 of Von-Mises stress is obtained in the impact
frontal test. With a great impact of cruising at a speed of 15.6464 m/s, 5.6053e−8 m deformation is obtained in the same test. As a result, the proposed EV battery pack design has showed the potential to improve the sustainability, performance, and ease of disassembly.
Many industrial and engineering problems are transformed into optimization problems and solved using various numerical based methods. One of the frequently used method is the Steepest descent algorithm which converge to the solution in only one iteration, given the current point and provided the quadratic function is positive definite. However, this method is not suitable for large scale functions because of lack of gradient information and high computational cost. This study aims to suggest a new conjugate gradient algorithm for motion control of robotic manipulators and unconstrained optimization models. The convergence result of the new algorithm would be discussed under some suitable conditions. Computational simulations are carried out on the discrete-time kinematics equation of a two-joint planar robot manipulator to illustrates the efficiency of the algorithm. The algorithm was further extended to unconstrained optimization problems in addition to motion control of robotic manipulators. Preliminary results prove that the new algorithm is efficient compared to the existing CG algorithm. The comparisons are made using the set of 50 standard benchmark functions including number of iterations and CPU time.
This chapter discussed the different approaches used for the evaluation of the health status of composite materials using nondestructive testing and evaluation (NDT&E) techniques. The discussion started with the terminology, proceeding to some general requirements of NDT in terms of performance, portability, and safety concerns. A description of the perception of defects and flaws vis-à-vis the different NDT techniques is also provided. A section was also devoted to personnel qualifications and certification as well as a brief introduction on the semantics of the most important formulations used in the NDT of composite materials. In the context of this book, NDT denotes a descriptive term used to indicate the examination of fiber-reinforced composite materials and components without changing or destroying their original attributes. Although the terms NDT and NDE are often used interchangeably in most of the literature (including some references in this chapter), these two terms are different and should be treated as such by the readers of this book consistent with the definitions outlined in the first section. Typical examples of the application of NDT are found in a number of fiber-reinforced composite structures including aircraft, spacecraft (i.e., space shuttle), motor vehicles, pipelines, bridge decks, refineries, buildings, and oil platforms which are all inspected using NDT. When used correctly, NDT can also serve as a Quality Assurance Management tool that can give impressive results, but this requires an understanding of the various methods available, their capabilities and limitations, as well as the knowledge of the relevant standards and specifications for performing the tests. In general, NDT can easily help identify materials, products, and equipment that fail to achieve their design requirements or projected life due to undetected defects and help schedule repair, maintenance, or replacement activities. NDT also helps engineers to mitigate unsafe conditions or catastrophic failure of composite structures, as well as the loss of revenue by providing an optimum window for timely planned repair and maintenance activities.
