Aun Haider | UET, Lahore (original) (raw)

Papers by Aun Haider

Ingenius, Revista de Ciencia y Tecnología

Modern fighter aircraft are equipped with multiple stations on the fuselage and under wings to ac... more Modern fighter aircraft are equipped with multiple stations on the fuselage and under wings to accommodate various external stores, both jettisonable and non-jettisonable. Each configuration undergoes airworthiness certification, including structural analysis of individual stations within the carriage flight envelope. This study focuses on the structural analysis of a wing station of a fighter aircraft within this specified envelope.

To perform this analysis, the wing station is extracted from the comprehensive global wing model, creating a sub-model with equivalent stiffness properties. Utilizing ANSYS Workbench®, Finite Element Analysis (FEA) is conducted for critical load cases to determine the Factor of Safety (FoS). The initial analysis reveals that the wing station has an FoS of 1.2 under the maximum design load. Prestressed modal and buckling analyses indicate a 10% increase in stiffness due to stress-stiffening effects.

To further enhance load-carrying capacity, parametric design changes are introduced. Increasing the bolt diameter from 8 mm to 10 mm raises the FoS to 1.33, resulting in an 8% increase in the maximum load-carrying capacity of the wing station. This comprehensive approach, employing FEA, ensures the structural integrity of the wing under static load conditions within the carriage envelope. The study's findings support the wing station's enhanced performance and contribute to safer and more efficient aircraft operations.

El Cereviz Journal of Science and Engineering, 2024

This paper highlights the importance of thorough documentation in Finite Element Analysis (FEA) s... more This paper highlights the importance of thorough documentation in Finite Element Analysis (FEA) studies to ensure transparency and reproducibility of results. It points out the lack of standardized guidelines for reporting and communication in FEA, which can lead to confusion and hinder evaluation. The paper aims to address this gap by proposing key reporting parameters covering various aspects of FEA studies such as analysis description, model identification, solver settings, and validation techniques. It emphasizes the significance of sensitivity analysis, verification, and validation for establishing the reliability of FEA models. The abstract concludes by advocating for the sharing of FEA models to promote scrutiny and improvement, using a case study to demonstrate how the proposed reporting parameters can enhance the quality and credibility of simulation studies. Additionally, it suggests that as modeling techniques evolve, the reporting parameters should also adapt accordingly, incorporating any supplementary factors that affect the accuracy of FEA models.

Aircraft Engineering and Aerospace Technology, 2024

This paper aims to comprehensively explore techniques for reducing solution time in finite elemen... more This paper aims to comprehensively explore techniques for reducing solution time in finite element analysis (FEA), addressing the critical need for expediting computations to facilitate agile design exploration within project timelines. Design/methodology/approach-Drawing from a wide array of literature sources, this paper synthesizes and analyzes various methodologies used to enhance the efficiency of FEA. Techniques are scrutinized in terms of their applicability, effectiveness and potential limitations. Findings-The review signifies application of linear assumptions across multiple facets of analysis and delves into matrix order reduction strategies, geometry simplification, symmetry exploitation, submodeling and mesh attribute control. It reveals how these techniques can effectively reduce computational burdens while maintaining acceptable levels of accuracy. Research limitations/implications-While this review provides a comprehensive overview of existing efficiency enhancement techniques in FEA, it acknowledges inherent limitations of any synthesis-based study. Future research should focus on refining these methodologies. Practical implications-The insights provided in this paper offer practical guidance for structural engineers and researchers seeking to optimize FEA workflows. By implementing these techniques, practitioners can expedite solution times and enhance their ability to explore design alternatives efficiently ultimately leading to cost savings and more robust structures. Originality/value-This review contributes to the existing literature by offering a comprehensive synthesis of efficiency enhancement techniques in FEA. By highlighting the originality and value of each discussed methodology, this paper provides a roadmap for future research and practical implementation in the field of structural engineering.

Pakistan Engg Council, 2021

The conceptual design of solar powered unmanned aerial vehicle (UAV) with perpetual flight for s... more The conceptual design of solar powered unmanned aerial vehicle (UAV) with perpetual flight for surveillance of longdistance gas pipelines is very much needed. The requirement of this surveillance platform has been conceived due to terrorist attacks on gas pipelines in Baluchistan. Nonconsumable and regenerative nature of the fuel used in solar powered UAV makes it an eternal plane under 24/7 energy balance. Such UAV operates as a terrestrial satellite, monitoring pipelines and transmitting real time imagery to control console. The requirement space was explored to select right specification matrix for the mission profile. The 24/7 flight endurance at 15,000 ft altitude during winter solstice is the key design constraint in addition to weight and power consumption of surveillance payload. Concept space was reconnoitered through Morphological Decomposition Matrix to select tail boom arrangement with non-retractable landing gears having multiple tractor electric propulsion units. Initial sizing is done to finalize Aspect Ratio and Wing span of baseline configuration. Detailed aerodynamic, propulsion, structural, stability, performance and cost analyses of this configuration are carried out to demonstrate conformance of all design requirements.

NED UNIVERSITY JOURNAL OF RESEARCH - STRUCTURAL MECHANICS

The wing of a fighter aircraft has various structural members which support aerodynamic and inert... more The wing of a fighter aircraft has various structural members which support aerodynamic and inertial loads, and transmit these loads to the fuselage. As a foremost step to evaluate the structural behaviour of the wing assembly, component contribution analysis is carried out. A finite element analysis of wing tulip of fighter aircraft isolated from the wing was performed under the design load case. Since aircraft wing is a statically indeterminate structure, reaction forces and moments at the supports depend upon the stiffness characteristics of the wing itself. In addition, stiffness of wing also affects the distribution of load and resulting deformation of the wing. These require that support structure of tulip isolated from the global wing model is represented by appropriate boundary conditions for the analysis. A comparative study for three boundary conditions (fixed support, nodal displacements and elastic support) was carried out to determine the representative boundary
condition for the analysis of structural members isolated from the global model. It was found that elastic support represents the stiffness of the global model and is a more appropriate boundary condition for the analysis of local models which are isolated from a global model.

ENFOQUE UTE, 2024

Aircraft operators often modify aircraft configurations, install new equipment, and alter airfram... more Aircraft operators often modify aircraft configurations,
install new equipment, and alter airframes to accommodate
this equipment, leading to operations in flight envelopes different
from original design profile. These modifications necessitate airframe
structural assessments, which typically require comprehensive
aircraft design data, often unavailable to operators. This
study aims to develop and validate a practical method for finite
element analysis (FEA) of aircraft structures in the absence of this
detailed design data. Focusing on a case study involving structural
analysis of an aircraft wing, this study presents assumptions and
idealizations used to develop 2.5D finite element (FE) model of the
wing. Fidelity of this model is established by comparing FE analysis
results with experimental data. Key validation metrics include
reaction forces, load distribution at wing-fuselage attachments,
and deformation at reference points on the wing under design
load. Comparison between FE analysis and experimental results
is carried out to substantiates accuracy of these geometric simplifications
and idealizations of load-carrying behaviour of structural
members. Therefore, practicality of these idealizations in absence
of design data is demonstrated. This study offers a novel approach
for structural assessments of aircraft without relying on proprietary
design data. The validated method enhances capability of
aircraft operators to perform effective structural analyses, thereby
extending service life of aircraft with continued airworthiness

NED UNIVERSITY JOURNAL OF RESEARCH - APPLIED SCIENCES, 2023

Solar-powered unmanned aerial vehicles (UAVs) with long endurance can be utilised for area survei... more Solar-powered unmanned aerial vehicles (UAVs) with long endurance can be utilised for area surveillance as the regenerative nature of solar energy makes such UAVs a terrestrial satellite with 24/7 endurance. This paper presents an aerodynamic optimisation scheme for UAVs through the selection of airfoils and wing planform during the preliminary design phase. Sizing of the tail and control surface based on historical trends for similar aircraft is also substantiated. Finally, detailed aerodynamic and stability analyses of the optimised configuration validate adequate flying and handling qualities of UAVs. The optimisation effort increased the endurance factor by 19.75 percent. This increase will conserve the energy required to overcome in-flight drag and surplus power that can be utilised by onboard equipment.

Reports in Mechanical Engineering, 2024

Solar-powered long-endurance unmanned aerial vehicles (UAVs) offer significant potential for vari... more Solar-powered long-endurance unmanned aerial vehicles (UAVs) offer significant potential for various applications due to their extended flight endurance. However, optimizing the design of solar-powered UAVs to achieve maximum efficiency and performance remains a complex challenge. The main objective of this research is to explore the sensitivity of solar-powered UAV mass to different design variables and technological constraints. The study employs a conceptual design methodology, iterating through various design configurations while specific design variables within bounds of historical data. Key parameters, including aspect ratio, wing span, payload mass, power consumption, cruise altitude, and technological constraints such as solar panel efficiency and battery energy density, are systematically varied to analyze their impact on UAV mass. The study also considers the influence cloud cover on solar power generation. This parametric study's results divulge solar-powered UAV mass's sensitivity to these design variables and technological constraints. By identifying key factors influencing UAV mass, the study offers actionable insights for designers and engineers in aerospace industry. The findings contribute to advancing the understanding of solar-powered UAV technology and lay the groundwork for future research and development initiatives to enhance UAV performance and efficiency.

Sciendo, 2024

This study addresses the challenge faced by Finite Element Analysts when choosing between free an... more This study addresses the challenge faced by Finite Element Analysts when choosing between free and mapped meshes, especially in terms of convergence stability and solution accuracy. The investigation focuses on 3D solid models under static structural loading, analyzed using Ansys® and MSC Patran®. Both free and mapped mesh types, employing equivalent 3D solid elements, are used to assess an aircraft structural component under design load conditions, with fixed boundaries. For free meshes, Tet10 elements in Patran (equivalent to Solid 72 in Ansys) are used, whereas for mapped meshes, CPENTA / CHEXA elements in Patran (equivalent to Wed6 / Hex8 in Ansys) are employed. Mesh convergence studies ensure that discretization does not affect the numerical solution. Notably, a significant stress increase is observed with successive refinement of free meshes, while mapped meshes achieve mesh independence at coarser refinement levels. Comparison of fringe plots indicates the same location for maximum deformation and equivalent stress in both free and mapped mesh models. The findings demonstrate that free meshes tend to underpredict maximum deformation and equivalent stress compared to mapped meshes, with both meshes showing deformation and stress at consistent locations. The findings underscore the importance of carefully choosing the appropriate mesh type, particularly when analyzing critical structural components, to ensure reliability and accuracy in FEA simulations.

Conference Presentations by Aun Haider

Conceptual design of solar powered unmanned aerial vehicle (UAV) with perpetual flight for survei... more Conceptual design of solar powered unmanned aerial vehicle (UAV) with perpetual flight for surveillance of long-distance gas pipelines is presented. The requirement of this surveillance platform is conceived due to terrorist attacks on gas pipelines in Baluchistan. Non-consumable and regenerative nature of the fuel used in solar powered UAV makes it an eternal‟ plane under 24/7 energy balance. Such UAV operates as a terrestrial satellite, monitoring pipelines and transmitting real time imagery to control console. Requirement space was explored to select right specification matrix for the mission profile. 24/7 flight endurance at 15,000 ft. altitude during winter solstice is the key design constraint in addition to weight and power consumption of surveillance payload. Concept space was reconnoitered through Morphological Decomposition Matrix to select tail boom arrangement with non-retractable landing gears having multiple tractor electric propulsion units. Initial sizing is done to finalize Aspect Ratio and Wing span of baseline configuration. Detailed aerodynamic, propulsion, structural, stability, performance and cost analyses of this configuration are carried out to demonstrate conformance of all design requirements.