Applied Mechanics and Materials Vol. 935

Abstract: This study analysed the buckling behaviour of thin-cylindrical shells under axial compression, addressing the persistent disparity between theoretical predictions and numerical simulations. The research investigated the influence of key parameters height, Young's modulus, and thickness on the critical buckling load. A Finite Element Analysis (FEA), specifically a Geometrically and Materially Non-Linear Analysis (GMNA), was performed using the software ABAQUS to model the shells. To bridge the gap between simulation and theory, a mathematical model for uncertainty analysis was developed in MATLAB, employing the Monte-Carlo Simulation (MCS) and referencing Rankine's theory. This study introduces a novel analytical framework that integrates Finite Element Analysis (FEA) and uncertainty analysis to resolve discrepancies in buckling predictions for thin cylindrical shells. The model's accuracy was validated with a maximum error of less than 13% compared to existing studies, and the uncertainty analysis demonstrated a robust standard deviation of 0.249 (less than 1%). The findings revealed that thickness is the most influential parameter; a 10% increase in thickness led to a 10.86% increase in the buckling load. Young's modulus had a moderate impact, with a 10% increase causing a 0.28% rise in the buckling load, while height was the least influential, with a 10% increase leading to only a 0.1% increase. This research provides valuable insights into the complexities of predicting critical buckling loads, highlighting the distinct impact of geometric and material properties on the structural behaviour of cylindrical shells.

Abstract: The freight transport sector, which primarily relies on heavy-duty diesel vehicles, accounts for approximately 25–30% of worldwide transport-related greenhouse gas (GHG) emissions, underscoring the critical need for decarbonisation. Hydrogen fuel cell commercial vehicles (HFCVs), otherwise, are emerging as a viable alternative for long-haul freight, strengthened by advancements in fuel cell technology and supportive national energy policies. Meanwhile, the battery electric vehicles (BEVs) excel in short- to medium-duty applications due to their high efficiency, but encounter challenges related to charging delays, infrastructure requirements, and reliance on the electrical grid. However, the HFCVs provide rapid refuelling and extensive ranges; yet they face obstacles due to elevated hydrogen prices, insufficient refuelling infrastructure, and fragmented policies. This review offers a comparative evaluation of hydrogen fuel cell vehicles, battery electric vehicles, and diesel vehicles in terms of technical, environmental, and economic factors, encompassing range, efficiency, lifecycle emissions, and infrastructure expenses. Moreover, this review outcome has indicated that China surpasses others in adoption due to robust national strategies at the same time, Europe gains from the Green Deal and Fit-for-55, and North America progresses through industry-led initiatives but faces challenges from fragmented regulations, with readiness indices of 3.8, 3.7, and 3.3, respectively. Realising scale necessitates synchronised policy, infrastructural investment, and intersectoral collaboration. This review study also provides empirical insights to inform sustainable freight transition strategies and emphasises HFCVs as a feasible alternative for decarbonising long-haul transportation.

Abstract: Heat losses from heating air ducts underground are used in many applications such as heating and air conditioning in cold weather. Researchers worked on heat losses to understand different ways to reduce heat losses to the environment. This project studies a 3-dimensional model of heating rectangular duct in cold surroundings. The model was done numerically. The numerical grid was tested to reach a reasonable approximation and a comparison with correlations from literature showed good agreement. Moreover, parametric study was carried out to study the effect of different parameters on heat losses. These parameters were Inlet velocity V_o, Inlet temperature T_o, outer heat transfer coefficient h_o, and surrounding temperature T_∞. Results showed that higher inlet velocity, inlet temperature, and outer heat transfer coefficient increases the total heat loss to the surroundings while higher surrounding temperature decreases the total heat loss to the surroundings.

Abstract: This research focused on noise reduction in jets using chevron passive control method, the nozzle designs with varying chevron types were subjected to CFD analysis and experimental analysis to understand pressure distribution patterns in the far field. This research distinctively analysed chevron performance through pressure distribution in the far field and not based on nozzle acoustic power dis-tribution, a surface phenomenon. Four models of nozzles namely base, chevron, wave and tabular were designed, manufactured and extensive analysis in both computational and experimental approaches was carried out. The sound pressure level (SPL) was calculated along with its percentage reduction for three models by taking the base model as reference model. The scientific results showed that among all models, wave is the least noisy with reduction of 3.3% and 1.16% SPL in computation and experiment respectively. On the other hand, the base model found to be the highest noisy model both computationally and experimentally.

Abstract: Ionic plasma thruster is advanced propulsion technology utilized for space applications. Scientific research remains focused on the development of efficient and effective thruster technologies for space exploration. The technology of ionic plasma thruster is notable for its ability to achieve high specific impulse and fuel efficiency. This study outlines our study on plasma and endeavours to enhance Ionic Plasma Thruster through the utilization of innovative methodologies and materials. The experimental setup utilizes electrodes energized by a 1000 kV power module and Lithium-Ion batteries. The design of electrodes is to enhance the concentration of flow electrons for a significant ionization, after ionization the discharged particles (ions) causes the thruster to the system. In addition to ameliorate the thruster, neodymium magnets are strategically positioned, and to expedite the movement of ions and improve the ionization processes. This paper arrays our study and development on plasma ionization and ionic plasma thruster thorough examination of our experimental configuration, methods, and initial findings. Our ongoing research and development efforts aim to expand the technology of ionic plasma thruster, with the goal of enabling more efficient, cost effective and sustainable space exploration missions.

Abstract: This paper presents a comprehensive structural, modal, and random vibration analysis of the SEAMS Payload using ANSYS 18.1 simulation tools. As a preliminary design-phase study, its goal is to perform a trade-off analysis between common aerospace materials before physical prototyping and validation. The study evaluates three aluminum alloys—5052- H32, 6061-T6, and 7075-T6—to optimize the payload frame structure for mechanical stresses encountered during launch and space operations. The analysis includes static structural loading to assess deformation and stress distribution, vibrational modal analysis to determine natural frequencies and mode shapes, and random vibration analysis to simulate launch-induced dynamic excitation. The simulation outcomes highlight the critical role of material selection in enhancing structural integrity, maximizing safety margins, and ensuring mechanical reliability of the payload in harsh launch environments.

Abstract: Across land, sea and air, nature has inspired researchers in countless ways, showcasing unique approaches to enhance grasping and manipulation techniques within robotics. The Flora and Fauna have served as ideas for enhanced flexibility, bending, maneuverability and adaptability for various grippers and manipulators in recent times. This study intends to explore the various fabrication methods, material choices and actuation processes used for these bioinspired robotic structures, as well as highlight the different applications, advantages and challenges. As traditional robots lacked the ability to work in unstructured environments and handle delicate operations, this triggered the need for bioinspired design. Through this paper, we connect the principles from nature to engineering, identifying the gap to achieve more efficient, versatile and durable robotic manipulators.

Abstract: The use of Unmanned Aerial Vehicles (UAVs) is increasing as their usage enhance many activities in our modern world. These include their specific roles in warfare, surveillance, agricultural activities, entertainments with attendant economic importance. In areas grappling with insecurity challenges due to banditry, kidnappings, oil spillage and theft, farmers and herdsmen clashes, utilizing more than one UAV in an area for surveillance is not only good but more advantageous. If many UAVs are used in an area at the same time, they are termed swarm or group of UAVs. Their operations in this manner, are seen as more scalable and reliable mode of using UAVs in current and future applications. Thus, usage of multiple UAVs that operate together as a cohesive unit are redundant and scalable, performing tasks that would be challenging or inefficient for a single UAV to accomplish. However, operating a group of UAVs as one unit can become expensive and risky if they are not properly coordinated. The UAVs may collide, causing catastrophic damage and requiring costly repairs. The need for autonomous coordination therefore comes from the vast number of vehicles, which might be intrinsic members of the system as a whole. Also, all UAVs in the swarm are to contribute to the effective execution of task without wasting resources. These imply that an intelligent coordination algorithm that implements awareness for swarm UAVs to avoid risky states is required. This paper presents the development and implementation of an algorithm for intra-swarm collision avoidance by treating each UAV in a swarm unit as individual agent capable of a homogenous number of tasks modelled as contours using their field of view and received signal strength indication.

Abstract: This paper proposes a conceptual framework for an intelligent soldier monitoring system, integrating multimodal sensor networks with Multimodal Large Language Models (MLLMs) to advance battlefield healthcare and situational awareness. The envisioned architecture combines physiological sensors (e.g., heart rate variability, cortisol levels, core temperature) with environmental sensors (e.g., acoustic, visual, thermal) through an edge-AI processing pipeline. Based on our literature review, we target three key limitations in existing systems: (1) real-time data fusion latency (aiming for <100 ms), (2) predictive health analytics accuracy (aiming for >90% for critical conditions), and (3) adaptive threat response capabilities. Our research suggests that the proposed technologies are at an early conceptual stage, supported by analysis of existing component technologies not yet integrated into a cohesive system. We identify challenges in power efficiency (targeting <50 mW per sensor) and ethical implementation, proposing solutions such as on-device processing and explainable AI. This work establishes a theoretical foundation and a research roadmap for future development of advanced military monitoring systems, balancing performance with operational and ethical considerations..