Abid Ali Khan

A research survey: review of flexible job shop scheduling techniques

In the last 25 years, extensive research has been carried out addressing the flexible job shop scheduling (JSS) problem. A variety of techniques ranging from exact methods to hybrid techniques have been used in this research. The paper aims at presenting the development of flexible JSS and a consolidated survey of various techniques that have been employed since 1990 for problem resolution. The paper comprises evaluation of publications and research methods used in various research papers. Finally, conclusions are drawn based on performed survey results.

Reviving a ghost in the history of technology: the social construction of the recumbent bicycle

Recumbent bicycles have never truly been associated with international cycling. Conventional safety (upright) bicycles have long been at the center of the cycling world, for both sport and transportation. This is despite the fact that recumbent bicycles are faster, more comfortable, and more efficient than the upright bicycles. The aim of this article is to explain the historical and social perspectives that led to the rejection of the recumbent bicycle by utilizing the theory of Social Construction of Technology (SCOT) and Bijker’s two power theory, providing a contrast with the adoption of the safety bicycle.

Object Oriented Case Representation for CBR Application in Structural Analysis

Knowledge representation is an essential element of a problem-solving technique through computational work. This article describes the knowledge representation scheme formulated to represent a problem in the structural analysis domain for solution through case-based reasoning (CBR). The numerical knowledge is extracted from a real-life problem that can be used as an input in a case-based reasoner. The geometric topology, loading, and mesh distribution for structure from a solved problem is represented in the form of numerical values for easy adaptation by the new problem. The representation scheme is a step forward in development of a system to be utilized for the time-consuming structural analysis requiring heavy computational power, such as an aircraft wing and fuselage components. The success of the representation strategy is a proof that CBR can work as a powerful problem-solving tool in this domain.Knowledge representation is an essential element of a problem-solving technique through computational work. This article describes the knowledge representation scheme formulated to represent a problem in the structural analysis domain for solution through case-based reasoning CBR. The numerical knowledge is extracted from a real-life problem that can be used as an input in a case-based reasoner. The geometric topology, loading, and mesh distribution for structure from a solved problem is represented in the form of numerical values for easy adaptation by the new problem. The representation scheme is a step forward in development of a system to be utilized for the time-consuming structural analysis requiring heavy computational power, such as an aircraft wing and fuselage components. The success of the representation strategy is a proof that CBR can work as a powerful problem-solving tool in this domain.

Buckling Load Prediction in Ortho-Grid Plates for Aerospace Structures

Iso-grid structures provide high strength with reduced weights, which is an essential requirement for aerospace applications. Buckling of Ortho-grid structure is a phenomenon with complex interaction between skin, stiffeners and sub-stiffeners. Introduction of sub-stiffeners increases the load bearing capacity of the structures many folds as compared to the classical Iso-grid or Ortho-grid structure. In this work, a customized MATLAB® code is developed for computational analysis based on finite element (FE) analysis. In case of FE analysis, the degenerated shell element is used. In the first phase of the MATLAB® code development, an elasto-plastic analysis of a clamped quadratic-shell is performed and the results are verified with the published literature. In the next phase, the buckling analysis of thin-plate is performed and the results are again verified with the literature. After verification of developed code, FE analysis of the Ortho-grid-stiffened plates is successfully validated. The results attained from developed code are compared with analysis performed on ANSYS® software along with the published work. The results revalidate the fact that stiffeners increase buckling load by over fifty times, which stands the main motive for their use in aerospace industry.

Computational and experimental studies of horizontal tail flutter suppression

Flutter is an extremely violent instability that may result in catastrophic failure. Thus, flutter clearance test is one of the critical phases in qualification of an aircraft’s airworthiness. During design and development process of an aircraft, flutter problems were experienced on an aerodynamic surface (horizontal tail). In order to tackle the observed problem, a number of approaches to optimize the design for flutter speed were computationally and experimentally studied and evaluated. This paper presents and discusses the outcomes of these studies. A hybrid approach based on evaluations and design change constraints has been proposed to suppress the flutter of the horizontal tail.

Residual Life Estimation of an Attach Angle for a Cargo Aircraft

Wing–fuselage attachment formally known as attach angle for cargo aircraft is an important component that connects the center wing to the fuselage. Owing to high wing loading, the edge and the center cracks on attach angle were detected and reported by users around the world. In this work, the critical edge and center crack lengths are computed using numerical techniques. The used procedure was first analytically validated for a simple case and then applied to original aircraft component. Based upon the critical crack lengths and crack-growth analysis, the remaining useful life of the attach angle has been estimated. Estimation of the remaining useful life for different parts of the aircraft at times become an essential requirement for aircraft operators, and the procedure adopted for this work can therefore be utilized for similar analysis of any aircraft part and would result in significant cost savings.

Heuristic-intelligent design schemes a solution paradigm for transatmospheric cruiser

Space planes are widely envisaged as the most viable solution for carrying out space activities in the future. The highly coupled natures of lift and propulsion mechanism in space planes limit the use of classical design approach. A paradigm shift in design methodologies is needed. Cognitive-intelligent methods must therefore be employed to evolve Heuristic-Intelligent Design Schemes that do not rely on archival data. These schemes must also be self-starting to avoid tedious recursions - hence inverse design approaches are recommended that can get integrated with heuristic-intelligent methods. A fast and frugal method based on high-fidelity approximate analytical formulation that uses hypersonic aerothermodynamics and energy partition principles must be resolved to evolve design solutions that simultaneously satisfy requirements for highly-integrated configurations as well as mass-model of transatmospheric cruisers. This paper briefly describes one such scheme called HI2D that can be used for designing, optimization and intelligent classification of spaceplane system configurations. The results of this scheme show significant improvement in the geometric and performance solution of baseline configuration.