Crash analysis of an aircraft fuselage under belly landing

Belly landing occurs when an aircraft lands without deploying its landing gear due to pilot error or mechanical failure. In the present work crash analysis of the fuselage under such belly landing is studied by numerical simulation using LS-DYNA software. In this study both the effect of sinking speed and the effect of different terrain properties on energy absorbing capacity is considered. Fuselage structure was modelled using LS-DYNA to simulate the crash analysis of the fuselage under vertical drop. The fuselage section similar to Boeing 737 aircraft was dropped at 7m/s and 10m/s on a rigid surface as well as on water and the deformations of fuselage were noted for each case and the energy absorbed by each of the components of the fuselage was evaluated. From the result obtained, it shows that frame and skin plays important roles in absorbing energy under crash

Finite element analysis of thermal stress intensity factors for cracked bimaterial system under convective cooling

Edge-crack bi material systems subjected to convective cooling is considered. The medium is assumed to be insulated on one surface and exposed to sudden convective cooling on another surface containing the edge crack. Superposition and uncoupled quasi-static thermo elasticity principles are adopted to find temperature and thermal stress distribution. The ANSYS results for the stress intensity factors of an edge crack are calculated and presented as a function of time, crack length, and thickness ratio for two different bimaterial systems, namely a stainless steel layer welded on ferritic steel and a ceramic layer coating on ferric stee

A matlab based educational software for the study on the effect of cut-out in aircraft wings

Cut-outs on aircraft wings are unavoidable due to the placement of fuel tanks and retraction of landing gear inside the wing. The stresses acting on an aircraft wing will deviate substantially before and after a cut-out is made and therefore it is crucial to perform stress analysis in an aircraft wing in order to ensure that the wing structure will be able to withstand the applied stress. Stress analysis of such structures is tedious and time consuming due to its statically indeterminate nature. A free stand-alone software based on MATLAB for the computation of stress due to the effect of cut-out in idealized wing torsion box has been developed. The main purpose is to provide the end-user (student or academic) a useful and user-friendly tool to perform preliminary stress assessment of the effect of cut-out analysis for an idealized wing

Experimental and numerical study on the aerodynamics and stability characteristics of a canard aircraft

Modern day fighter aircrafts are mostly canard configured because of its advantages over conventional configuration. The primary objective of this work is to investigate the low speed aerodynamic and stability characteristics of a canard configured aircraft. Using CFD -ANSYS Fluent package, numerical flow simulations were carried out for a typical canard configuration such as Burt Rutan’s VariEze, a composite homebuilt canard aircraft. To validate the numerical results, wind tunnel testing of a scaled model was carried out. Finally the effect of horizontal location of canard on the aerodynamics and stability characteristics was studied

Experimental study of impact on carbon-fiber-epoxy composite wing leading edge structure

This paper works on the curvature composite structure for wing leading edge application using fabric carbon/epoxy material subjected to impact loading. At first stage, rigid spherical projectile and elliptical panel with were used. The impact testing has been carried out by varying the radius of curvature, the thickness of the panel and different stacking sequence. The experimental results show the trend of specific energy absorption capability of structure in function of the radius, thickness of panel and carbon fiber directions

A new higher order theory for analysis of orthotropic cylindrical shell under electromechanical load

In this work, the effect of electrical loads on the bending behavior of a simply supported cylindrical shell made of composite and piezoelectric layups have been considered. A new 8 terms higher order shear deformation theory (HSDT8) is proposed and used to analyze the problems. The HSDT8 is the extensional of FSDT by incorporating Murakami zig-zag function and higher order terms in the displacement model. Results are presented for mechanical and electromechanical loading for various layups and validated against available elasticity solutions. HSDT8 proves to be an accurate model for all cases, thin and thick laminate problems

Educational software for stress analysis of non-idealized closed thin-walled sections

Aerospace structures such as fuselage and wings are made of typical thin-walled closed sections and the detailed stress analysis of such closed thin-walled structures can be tedious and time consuming due to its statically indeterminate nature of the problem. In the present work, an educational software for the stress analysis of such non-idealized thin-walled closed sections has been developed that complements tradi-tional methods of teaching and learning. The software developed is able to generate any given closed cross section which are subjected to bending, shear, and torsional loads and compute the resulting stresses on the cross section. Results from literature have been used to validate the results from the software. The software has been developed using Graphical User Interface (GUI) in MATLAB which makes the soft-ware very user friendly. The software is expected to be an effective teaching and learning tool of courses on thin-walled structures and air-craft/automotive structures

Shape control of composite plates with piezoelectric actuators

In this paper, shape control of composite plates using piezoelectric actuators is being investigated. The goal of this study was to see how composite plates behave when they are integrated with piezoelectric actuators. Modelling and simulation were done using COMSOL Multiphysics software and results were validated using previously published studies. Parametric investigations were carried out to inves-tigate the effect of patch locations and stacking sequences with respect to suppression of deflection. The obtained results showed that for uniformly distributed load considered in this work the patches worked effectively when they were placed at the center of the composite plate

Application of machine learning with impedance based techniques for structural health monitoring of civil infrastructure

Increased attentiveness on the environmental and effects of aging, deterioration and extreme events on civil infrastructure has created the need for more advanced damage detection tools and structural health monitoring (SHM). Today, these tasks are performed by signal processing, visual inspection techniques along with traditional well known impedance based health monitoring EMI technique. New research areas have been explored that improves damage detection at incipient stage and when the damage is substantial. Addressing these issues at early age prevents catastrophe situation for the safety of human lives. To improve the existing damage detection newly developed techniques in conjugation with EMI innovative new sensors, signal processing and soft computing techniques are discussed in details this paper. The advanced techniques (soft computing, signal processing, visual based, embedded IOT) are employed as a global method in prediction, to identify, locate, optimize, the damage area and deterioration. The amount and severity, multiple cracks on civil infrastructure like concrete and RC structures (beams and bridges) using above techniques along with EMI technique and use of PZT transducer. In addition to survey advanced innovative signal processing, machine learning techniques civil infrastructure connected to IOT that can make infrastructure smart and increases its efficiency that is aimed at socioeconomic, environmental and sustainable development

Experimental observation of Jute/Epoxy composite plate subjected to impact loading

World is currently focusing on alternate material sources that are environment friendly and biodegradable in nature. Due to the increasing environmental concerns, biocomposite made from natural fibers and polymeric resin, is one of the recent developments in the industry and constitute the present scope of experimental work. This work presents elaborate explanation on advantages, mechanical and physical behavior of jute fiber–epoxy composites, one of the renewable alternatives. The bicomposite is experimentally investigated in case of low velocity impact loading. The experimental observations in term of damage mechanism, maximum force and maximum energy absorption are studied to understand the effect of fiber orientation. A comparative study with typical synthetic fibers like carbon or glass is also conducted. The characterization tests on jute-epoxy show that the tensile behavior is non linear as found for carbonepoxy or glass-epoxy plate