AIRCRAFT STRUCTUREFAILURE PROJECTMembers:Amirul Iman B. Hasri AD110155Jaswant Singh Bal A/L Hadip Singh AD110177Amal Iqmal B. Adnan AD110189FACULTY OF MECHANICAL &MANUFACTURINGENGINEERINGAIRCRAFT STRUCTURESBDU20103http://www.dnv.com/binaries/PULS-buckling_tcm4-284864.JPG
APRIL 28, 1988 At 13.25 P.MA Boeing 737-200 operated by Aloha Airlines as flight 243 take off from Hilo andits destination was to Honolulu, Hawaii. The first officer flew the plane while thecaptain handle the radio communications with the air traffic control (A.T.C). At 13.46 P.MAfter just 21 minutes into the flight, , they experienced an explosivedecompression and structural failure at 24,000 feet. Part of the front of thefuselage tare apart. First 5 rows were exposed completely to the sky.Approximately 18 feet of the cabin skin and structure of the cabin entrance doorand above the passenger floor line separated from the airplane during flight.Both pilots immediately take action:Captain- control the plane & First officer- contact traffic control at Maui cause itwas listed as the alternate landing airport.
Continue…. At 13.50 P.MThe tower able to contact the pilots. So the pilots request an emergencylanding and equipment. They notice that the door at the fuselage is missing. At 13.55 P.MCaptain request ‘ flight control manual inversion ’ ( used when hydraulicsystem and power steering malfunction) by using the controlling yolk.He puts the landing gear down and changes flap from 15 to 5 ( constantlychange the flaps to get the precise speed landing).They safely land the aircraft at Kahului Airport on the Island of Maui.There were 89 passengers and 6 crewmembers on board. One flightattendant was swept overboard during the decompression and is presumedto have been fatally injured. 7 passengers and 1 flight attendant receivedserious injuries.
The Boeing 737 was designed for safe decompression in which a smallhole acts as a valve to keep interior pressure from blowing the planeapart. But boiler engineer Matt Austin says the design does not work ifsomething momentarily blocks the hole.1. At 24000ft, forces exerted on the fuselage which had a crack alongrivet holes above the windows-open a 10-inch-square safe-decompression hole in the roof.
2. Air from the pressurized cabin begins to rush out at about 700mph.A flight attendant is sucked into, but not through, the opening. Thisshuts off the rush of escaping air for a few ten-thousandths of asecond and pressure builds up to hundreds of pounds per squareinch-powerful enough to rib the plane apart. The side of the planeblows out and downward, while the roof section peels up toward thecenter. A section of the windows folds toward the rear, trapping theflight attendant.
3. The window folds over, tearing back to a reinforced joint,slamming against the fuselage. On the outside of the jet, blood anda mark that Austin says is a skull print are found. Austin says that thesuggests the attendant’s body blocked the safe-decompression holeinstead of being immediately swept clear of the aircraft.
The Finite Element Method(FEM) is based on theidea of building a complicated object with simpleblocks, or, dividing a complicated object intosmall and manageable pieces. Application ofthese simple idea can be found everywhere ineveryday life, as well as in engineering.
1943-Courant(Variational Methods) 1956-Turner,Clough,Martin, & Top(stiffness) 1960-Clough(FE, plane problem) 1970-Application on mainframe computer 1980-Microcomputers 1990-Analysis of large structural system
Design analysis-hand calculation, experiment,and computer simulation This is the most widely applied computersimulation method in engineering. Closely integrated with CAD/CAM applicationslike AutoCAD.
One of several numerical methods that can be used to solve complexproblems and is the dominant method used today. As the nameimplies, it takes a complex problem and breaks it down into a finitenumber of simple problems. A continuous structure theoretically has an infinite number of simpleproblems, but finite element analysis approximates the behavior of acontinuous structure by analyzing a finite number of simpleproblems. Each element in a finite element analysis is one of these simpleproblems. Each element in a finite element model will have a fixednumber of nodes that define the element boundaries to which loadsand boundary conditions can be applied. The finer the mesh, the closer we can approximate the geometry ofthe structure, the load application, as well as the stress and straingradients.
ANSYS offers a comprehensive range of engineering simulationsolution sets providing access to virtually any field of engineeringsimulation that a design process requires. Companies in a widevariety of industries use ANSYS software. ANSYS is a finite element analysis (FEA) code widely used in thecomputer-aided engineering (CAE) field. ANSYS software allows engineers to construct computer models ofstructures, machine components or systems which apply operatingloads and other design criteria and study physical responses, such asstress levels, temperature distributions, pressure and others. It permits an evaluation of a design without having to build anddestroy multiple prototypes in testing.
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