FTA of Main Landing Gear Systems

FTA of Main Landing flip SystemsFTA OF MAIN LANDING GEAR SYSTEMSMain Landing Gear SystemFor any aircraft come huckster is the undercarriage which support the craft when its not flying, until it to take slay and during landing. Landing gear hold net weight of whole aircraft during taxing without any damage.Fig A380 briny landing gear configurationComp geniusnts of landing gearThe materials used to construct gear components ar of with child(p) importance and ar selected as per their propertiesThe of import components of landing gear areDown-lock and drag brace retraction actuators, Rotational actuatorsTrunnionForward trunnion bracesMetering pin extensionRotational LockpinsAft bracesOleo cylinderOleo pistonAxle channel fold and compensation actuatorBrake assemblyTires and wheelsSensing wheelAxle beam assembly misfortune of lading gearIn this part we discussed about the Ductile and Brittle Failure, hear Corrosion Cracking, Stress Rapture, Fatigue Cracking Failure Dynamic Fai lure, Landing gear Spring Failure and Wheel Failure. We died these possible enigma and construct suitable jailbreaking manoeuvre analysis in order to report unsuccessful person match in brief.The objective of constructing the gap manoeuver is to investigate and analyze the possible sorrows and different components and systems of the landing gear with their consequences and solutions.In the subject plain stitch of mechanical failuresThere are 12 types of failuresExcessive, deflection , thermal shock, impact creep, relaxation, brittle fracture, ductile fracture, wear, spring, failure, corrosion, stress corrosion gap, and various type of fatigue. On the basis of this problem that can occurs in principal(prenominal)(prenominal)(prenominal) landing gear we construct the fault channelize to identify the failure condition and met the requirements.Materials for landing gearThe materials used for the landing gear are juicy strength steelTitaniumAluminumFailure mechanism of landing gearFatigue cracking failureMostly aircrafts and military experience serious damage and the fatigue.Stress corrosion crackingThis SCC is bring forthd by synergy between a corrosive environment and a mechanical tensile streeDynamic failureWhen aircraft land on the state tricycle landing gear and load affected by the ground/pavement response are distributed on the and can cause problem.Landing gear spring failureHere micro cracks acted as stress concentration as well initiation crack send leading the spring to fracture due to fatigueWheel failureDuring landing wheel experience a lot of pressure. Due to this over pressure that could damage4.2 The fault tree of typical main landing gear systemThe main purpose of constructing fault tree is, in order to identify the possible failure of any system which can occurs in any manner.In case of main landing gear, fault tree can be construct on the basis of two main conditionsFault tree analysis for failure condition 511 one or some( prenominal) MLG fail to cut across and slash lock with fictional down and locked indication.Fault tree analysis for failure condition 511 one or both MLG fail to extend and down lock.Between these two failure conditions of main landing gear, I choose to analyzed fault tree analysis for failure comdititon511 one or both MLG fail to extend and down lock with false down and locked indication.The analysis based on fault treeMy main object of constructing this fault tree is to identify the typical failure condition of main landing gear in order to save aircraft from its hazardous failureAs we want to take safety procedure for every parts of aircraft, landing gear is also aspect which cause aircraft in a dangerous modeSo in order to surmount this failure of landing gear and for the safety of aircraft, I finally decide and came to know the purpose of failing landing gear and what can be the cause for this.With the help of fault tree analysis, we analyzed the each and every problem insi de the landing gear and try to overcome by constructing fault treeIn case of LH or RH or both MLG fail to extend and down lock with false down and locked indication, pilot receive alert. So while construction fault tree we take as a main event by using event type as shown in fault tree.After we decided main event than we analyzed for the cause of it by using the Boolean symbol called AND gate. We use AND gate so that we could analyze all next veritable lour aim condition which can possibly occur. Possible cause of man landing gear are false LG down position indication and LH or RH MLG fail to extend and down lock. Still at that place are some cause to fail these two components, which we allow define by Boolean logical system symbol call OR gate. The purpose of OR gate is to identify among of various possible problem if any of one or more of the next lower level event are true for failure of above condition.In fault tree analysis we solved the problem and come to the oddment w ith what if, and with the help of various Boolean logic symbols. The main event that I mention in the make pass is not only the problem that cause landing gear to fail but also the lower level parameters which fails landing gear fails. When we look from external and if landing gear is not extend during landing than we conclude that the landing gear doesnt work. But besides engineer who work in the field of safety assessment, other observer will just guess just the landing gear fail. We neer thought of what cause the landing gear fails. As per landing gear consists various components so the chance of failure also high. If small components for example spring fails, than the landing gear fail.so in order to overcome these all possible failure fault tree is constructed.Among of various symbols and representation, AND and OR gate plays vital type to make all possible decision for failure.Determination of stripped cut set for fault tree analysisMinimal cut set is define as a combinat ion of primary events suitable for the top event, on other words intersection of primary event. The main objective of representing a fault tree in terms of various Boolean equations is that these equations can then be used to trammel the fault trees stripped cut sets and nominal path sets. While we obtain the stripped cut set, the quantification of the fault tree is more or less straightforward.For every fault tree will consists of finite number of minimal cut sets that are unique for that event. There are two agreeable of minimal cut sets which can occurs the top event to occur. One components minimal cut sets, if there are any, represent those single failures that will cause the top event to occur. Whereas two-components minimal cut sets represents the double failures that unneurotic will cause the top event to occur. Similarly for an n- components minimal cut set, all n components in the cut set must fail in order for the top event to occur.The calculation of minimal cut-s etsThe minimal cut sets expression for the top event can be written as in the general formT = M1 + M2 ++Mk,Here the terms T is the top event and Mi are the minimal cut sets.Whereas for the each minimal cut sets for n-components minimal cut set can be represents asMi = X1X2., XnHere the X1 and X2 , etc represents the basic components failure in the fault tree analysisI represents my above failure events as ABC, T is top event caused by all lower level events. Here I want to mention the example of top event expression isT = A + B.CHere A, B and C are components failures. In this example A represents the one-components minimal cut set whereas B.C represents the tow-components minimal cut set.In order to determine the minimal cut sets of a fault tree, the tree should be translated first to its equivalent Boolean equations.Here I want to mention the example of calculation the minimal cut set to my fault treeThe procedure to calculate the minimal cut sets of fault treeT = E1.E2 being AN D gateE1 = A+ E3 being OR gateE3 = B+C being OR gateE2 = C+E4 being OR gateE4 = A.B being OR gate alter the top down first the expression of minimal cut can be expressed as belowT = (A+E3) . (C+E4)= (A.C) + (E4.C) + (E4.A) + (E3.E4)Substituting for E3,T = (A.C) + (B+C).C + E4.A + (B+C). E4= A.C + B+C + C.C + E4.A + E4.B + E4.CHere according to idempotent law, C.C = C, interchange this value to above equationsT = A.C + B.C + C + E4.A + E4.B + E4.C.Again according to the law of absorption twice, A.C + B.C + C + E4.C = CThen the above results become,T = C + E4.A + E4.BHence, substituting for E4, applying the law of absorption twice,T = C + (A.B).A + (A.B).B= C + A.BThe minimal cut sets are thus C and A.B where, C is one- components and A.B is two-components minimal cut sets.