Saifulnizan Jamian

Directly recycled AA6061, valued for its energy-efficient production and reduced environmental impact compared to primary aluminium, exhibits unique mechanical properties due to microstructural changes during recycling. Behavioural analysis under various loading conditions, including tensile and impact tests, reveals mild ductility and anisotropic deformation patterns such as petal formation, plugging, and fragmentation. This study investigates the fracture and perforation behaviour of AA6061 plates under high-velocity impacts using a numerical model based on the Johnson-Cook material and failure models. Simulations of Taylor cylinder impact tests, conducted at velocities ranging from 280 m/s to 370 m/s, show strong agreement with experimental data, validating the Simplified Johnson-Cook model’s effectiveness in predicting fracture behaviour under impact loading. Building on these results, the study explores the Johnson-Cook Failure Model in perforation tests with severely fractured specimens. Simulations accurately predict perforation behaviour at lower impact velocities and smaller bullet diameters, particularly in cases of limited deformation. However, at higher velocities and larger bullet diameters, prediction accuracy decreases due to complex fracture patterns and asymmetric deformations. The study concludes that while the current failure model provides a foundational understanding of fracture and perforation behaviour in recycled AA6061, further refinements are necessary. Enhancing the failure model, specifically for recycled aluminium, could improve its predictive accuracy across a broader range of impact scenarios, addressing the limitations observed in cases of severe deformation and complex fracture mechanisms.

In geometrical localization techniques, the propagated signal’s first-order multipath (FOMP) characteristics are used to calculate the location based on geometrical relationships. Utilizing the characteristics of higher order multipath (HOMP) results in a significant localization error. Therefore, distinguishing between FOMPs and HOMPs is an important task. The previous works used traditional methods based on a deterministic threshold to accomplish this task. Unfortunately, these methods are complicated and insufficiently accurate. This paper proposes an efficient method based on supervised learning to distinguish more accurately between the propagated FOMP and HOMP of millimeter-Wave Vehicle-to-Vehicle communication in an urban scenario. Ray tracing technique based on Shoot and Bounce Ray (SBR) is used to generate the dataset’s features including received power, propagation time, the azimuth angle of arrival (AAOA), and elevation angle of arrival (EAOA). A statistical analysis based on the probability distribution function (PDF) is presented first to study the selected features’ impact on the classification process. Then, six supervised classifiers, namely Decision Tree, Naive Bayes, Support Vector Machine, K-Nearest Neighbors, Random Forest, and artificial neural network, are trained and tested, and their performance is compared in terms of HOMP misclassification. The effect of the considered features on the classifiers’ performance is further investigated. Our results showed that all the proposed classifiers provided an acceptable classification performance. The proposed ANN showed the best performance, whereas the NB was the worst. In fact, the HOMP misclassification error varied between 2.3% and 16.7%. The EAOA exhibited the most significant influence on classification performance, while the AAOA was the least.

Due to the extensive usage in the industry, the structural integrity of hollow cylinders is seen as a critical goal for stakeholders. Fracture is the most common failure mode for cylinders, which occurs due to crack propagation. Cracks can be found in single or multiple forms; when numerous, crack interaction occurs, which can exacerbate pressures beyond the material's resistance. This work uses Ansys software to examine double parallel interacting surface cracks on a hollow cylinder. The stress intensity factor (SIF) was used to describe the driving force that was used to characterize crack interaction for various crack geometries. To conduct extensive research, this study evaluated a wide range of crack aspect ratios as well as the relative depth of the crack. The findings of this study indicated that the shielding effect demonstrated parallel crack interaction. In addition, an empirical mathematical approach for predicting SIFs for double parallel cracks via single crack SIFs has been developed. The validation of the proposed model using performance evaluation metrics revealed an acceptable rate of error of less than 5%.

The reinforcement materials on aluminium metal matrix composites are commonly used in the industrial sector due to their light-weight, improved fracture toughness, superior strength-to-weight ratio, and improved mechanical properties. This study investigates the effect on composition of peat soil as reinforcement on AA6061 aluminium chip to hardness and physical properties of metal matrix composite. AA6061 aluminium chip reinforced with peat soil at various composition prepared by using cold compaction technique were investigated. Due to the lower operating cost and energy consumption compared to conventional recycling by casting, this method was applied to study the hardness and physical properties of metal matrix composite samples. As a result, the addition of composition of peat soil shows improvement in term hardness and physical properties for composite compared to unreinforced AA6061 aluminium chip. The hardness of AA6061 aluminium chip has enhanced with increasing the composition of peat soil from 45.2826 Hv to 52.3120 Hv at an addition of 2.5 wt.%. The highest hardness shows with an addition of peat soil at 10 wt.% at 65.1069 Hv, however the porosity results shows that the samples have higher pores due to the larger amount of composition added. The physical properties on density of metal matrix composites samples shows the increment up to 5 wt.% of peat soils, and then decreased at increasing mass fraction of peat soil. The addition of peat soil at 7.5 wt.% as reinforcement material shows the improvement of hardness with light-weight on metal matrix composite samples.

Observing the vehicles movement becomes an urgent necessity due to exponentially increasing numbers of vehicles in the world. However, to this regard, a good deal of research had been presented to estimate the exact physical position of the vehicle. The major challenges faced vehicle localization systems are large coverage areas required, positioning at diverse environments and positioning during a high-speed movement. However, in this paper, the challenges of employing the vehicle localization techniques, which rely on the propagation signal properties, are discussed. Moreover, a comparison between these techniques, in terms of accuracy, responsiveness, scalability, cost, and complexity, is conducted. The presented positioning technologies are classified into five categories: satellite based, radio frequency based, radio waves based, optical based, and sound based. The discussion shows that, both of satellite-based technology and cellular-based technology are emerge solutions to overcome the challenges of vehicle positioning. Satellite-based can provide a high accurate positioning in open outdoor environment, whereas the cellular-based can provide accurate and reliable vehicle localization in urban environment, it can support non-line of sight (NLOS) positioning and provide large coverage and high data transmission. The paper also shows that, the standalone localization technology still has limitations. Therefore, we discussed how the presented techniques are integrated to improve the positioning performance.

This research is intended to investigate the ability of shape memory alloys (SMA), through its activation, in generating loads to control beam deflection. An elastic beam is formed by sandwiching eccentrically SMA wires between two elastic plates. SMA wires are activated by electrical current from the power supply. Laser displacement meter (LDM) is used to measures deflection of sample. Results show that the deflection of the beam is dependent on the temperature change. The temperature-deflection response also shows the existence of hysteresis.

Process-induced residual stress in shape memory alloy (SMA) fiber reinforced aluminum (Al) matrix composite was simulated by ANSYS APDL. The manufacturing process of the composite named as NiTi/Al is start with loading and unloading process of nickel titanium (NiTi) wire as SMA to generate a residual plastic strain. Then, this plastic deformed NiTi wire would be embedded into Al to become a composite. Lastly, the composite is heated form 289 K to 363 K and then cooled back to 300 K. Residual stress is generated in composite because of shape memory effect of NiTi and mismatch of thermal coefficient between NiTi wire and Al matrix of composite. ANSYS APDL has been used to simulate the distribution of residual stress and strain in this process. A sensitivity test has been done to determine the optimum number of nodes and elements used. Hence, the number of nodes and elements used are 15680 and 13680, respectively. Furthermore, the distribution of residual stress and strain of nickel fiber reinforced aluminium matrix composite (Ni/Al) and titanium fiber reinforced aluminium matrix composite (Ti/Al) under same simulation process also has been simulated by ANSYS APDL as comparison to NiTi/Al. The simulation results show that compressive residual stress is generated on Al matrix of Ni/Al, Ti/Al and NiTi/Al during heating and cooling process. Besides that, they also have similar trend of residual stress distribution but difference in term of value. For Ni/Al and Ti/Al, they are 0.4% difference on their maximum compressive residual stress at 363K. At same circumstance, NiTi/Al has higher residual stress value which is about 425% higher than Ni/Al and Ti/Al composite. This implies that shape memory effect of NiTi fiber reinforced in composite able to generated higher compressive residual stress in Al matrix, hence able to enhance tensile property of the composite.

1. Dr. Abdul Latif Mohd Tobi Structural Integrity and Monitoring Research Group (SIMReG) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: abdlatif@uthm.edu.my 2. Dr. Al Emran Ismail Crashworthiness and Collisions Research Group (COLORED) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: emran@uthm.edu.my 3. Assoc. Prof. Dr. Waluyo Adi Siswanto Sports Engineering Advancement Research (SPEAR) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: waluyo@uthm.edu.my 4. Dr. Saifulnizan Jamian Crashworthiness and Collisions Research Group (COLORED) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: saifulnz@uthm.edu.my 5. Mr. Mohd Amran Hj. Madlan Noise and Vibration Analysis Research Group (NOVIA) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: amran@uthm.edu.my 6. Dr. Nor Azali Azmir Noise and Vibration Analysis Research Group (NOVIA) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: azali@uthm.edu.my 7. Dr. Noormaziah Jafferi Advance Dynamics Control and Automation Research Group (ADCARe) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: normazia@uthm.edu.my 8. Dr. Eliza M Yusup Sports Engineering Advancement Research (SPEAR) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: elizay@uthm.edu.my 9. Dr. Kamarul Azhar Kamarudin Crashworthiness and Collisions Research Group (COLORED) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: kamarula@uthm.edu.my 10. Dr. Ong Pauline Advance Dynamics Control and Automation Research Group (ADCARe) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: ongp@uthm.edu.my 11. Dr. Zaleha Mohamad Structural Integrity and Monitoring Research Group (SIMReG) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: zaleha@uthm.edu.my 12. Dr. Noradila Abdul Latif Structural Integrity and Monitoring Research Group (SIMReG) Department of Engineering Mechanics, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor, MALAYSIA Email: noradila@uthm.edu.my

Steel slag is a by-product from steel industry and it contains variety of hazardous materials. In this study, the dissolution behaviour and removal potential of hazardous materials from steel slag with the wet grinding method was investigated. The slag was wet ground in the CO₂ atmosphere and the slurry produced was filtered using centrifugal separator to separate the liquid and solid sediments. Then, the concentrations of dissolved metal elements in the liquid sediment were analyzed by ICP-MS. The changes of pH during the grinding were also investigated. It was found that the pHs were decreased immediately after the CO₂ gas introduced into the vessel. The pHs were ranging from 6.8 to 7.6 at the end of grinding. The dissolved concentration of Zn and Cr were ranging from 5~45 [mg/dm³] and 0.2~2.5 [mg/dm³] respectively. The ratios of Zn removal for stainless steel oxidizing and reducing slag were very high, but those from normal steel oxidizing and reducing slag were very low. It is assumed that the Zn dissolved as ZnOH⁺ from Zn(OH)2 that formed due to the reaction between ZnO and water. Dissolution of Cr also occurred but in very low quantity compared to the dissolution of Zn. The dissolution of Cr occurred due to the grinding process and small amount of Cr(OH)₃ was formed during the grinding. This small formation of Cr(OH)3 resulted to the low dissolved concentration of Cr in the form of Cr(OH)2⁺. According to the XRD analysis, the Cr mostly existed in the slags as Cr(IIl) in the form of MgCr₂O₄ and FeCr₂O₄.