, GIR. VUMISIIS usn | 18AE53 Fifth Semester B.E. Degree Examination, June/July 2023 Aircraft Structure - 1 Max. Marks: 100 Time: 3 hrs. ‘h module. Note: Answer any FIVE full questions, choosing ONE full question from eacl Module-1 1a. Define Draw the stress ~ strain curve for i) Ductile material ii) Brittle material and explain the salient features. (10 Marks) b. Why failure theory is important for designing any components? Explain the types of failure theories m detail (10 Marks) oR 2 a. Explain the codes and standards used in design. (10 Marks) b. The load on a bolt consists of an axial pull of ]OkN together with a transverse shear force of SKN. Find the diameter of bolt according to i) Maximum principal stress Theory ii) Maximum shear stress theory iii) Maximum principal strain theory iv) Maximum strain Energy theory (10 Marks) Modul 3 a. Define Fatigue. Draw S-N diagram and explain its features. (0 Marks) b. Define Endurance limit. Explain the factors that effects the enduranee lint, (G0 Marks) OR 44, Discuss the stresses due to combined loading. (10 Marks) b. Derive the Goodman and Soderberg relationship for combination of stress (10 Marks) Module-3 5 2. What is Gust? Explain the Gust Envelope and its significance with suitable diagram, (10 Marks) The aircraft shown in Fig Q5(b)-i) weighs 135KN and has landed such that, at the instant of inypaet, the grand reaction On each main under carriage wheel is 200KN and its vertical velocity is 3.5m’s. each under carriage wheel weighs 2.25KN and is attached to an also strut as shown in Fig Q5(b)-ii), calculate the axial load and bending moment in the strut, the strut may be assumed to be vertical. Determine also shortening of the strat when the vertical velocity of the aircraf is zero. yor Fig QS(b)-i) (10 Marks)I8AES) oR ‘What is a composite material? Explain the types of composite nm and its uses. ik b. Listout the desirable properties of a material to be considered in Aircraft ap aterials based on its metrics (10 Marks plications (10 Marks) odule-d i Med 7a. A plane element in a boiler is subjectedito tensile stresses of 40MPa on one plane and 1S0MPa on the other at right angles 10 the former. Each of the above stresses is accompanied by a shear stress of 100MPa such that when associated with the minor tensile stress tends to rotate the element in anticlockwise direction. Find i) Principal stress and their directions ii) Maximum shearing stresses and the directions of the plane on whieh they act (10 Marks) b. Derive the equilibrium equations in 3-dimensions for the state of stress. OR 8 a, Differentiate between statically determinate and indeterminate structures. (06 Marks) b. Determine the forces is all the members of a cantilever truss as shown in Fig Q8(b). » oH Sew Fig Q8(b) (14 Marks) Module-5 9 a. State and prove the method of least work. (10 Marks) b. A steel rod of 50mm diameter is 4m long, Find the stress and stretch in the rod if'a load of ‘SOKN is applied i) Gradually ii) Suddenly. Also find the strain energy stored in the rod. under the given conditions, Take E = 200kN/mm* (10 Marks) OR ‘What are the assumptions made in Euler's column Theory? Derive the formala for clipping Joad for a column with both ends hinged condition, (12 Marks) w alloy tube 4m long with external and internal diameters of 40mm and 20mm. was found to extend 4.8mm under a tensile load of 6OKN Find the buckling with both ends pinned. Also find the sali load on the tube, taking a factor (08 Marks) eens 2of2vv (TTT Fifth Semester B.E. Degree Examination, Jan/Feb, 2023 Aircraft Structures - I Max. Marks:100 FIVE full questions, choosing ONE full question from each module. Modute-1 - Define state strength, biaxial sys, stress tensor, principal tess and fictor of safety A propeller mounted on a°40Qmm diameter solid shafl producer a torque of 4500Nm and thrust of 90KN, Determine te maximum normal stfess and maximum shear stress developed inthe member. (10 Marks) oR Explain any two'theories of failure most stable for ductile materials. (08 Marks) « ‘A cylindgial boiler of 2m diameter made of sheet metal 20mm thick, is subjected to an intemnal’pressure of 1.SMPa, Find the factor of safety ysing meximum principal stress theoryamaximum shear stress theory maximum princig@l, Strain theory, maximum strain energy theory and maximum shearstrain energy theorgsTake 0, ~ 350 MPa and y= 0.25. (12 Marks) 5. we on the esnng blk pages Module-2 Define impact stress and/Werive the equation forthe same. Also amtive at the equation for impact factor. (0 Marks) Draw a SN diagrdar and explain endurance strength, Discuss the Factors on which endurance strength depends: (10 Marks) or Define sitss concentration fagior Discuss how stfess concentration effects can be reduced with deat sketches (10 Marks) A cantilever beam made, dt Steel of circular section as shown in FigQ4(b). Determine the ‘maximum load it can withstand for an indefinite life based on Goodman and Soderberg ‘rileria. Use a factorof afety as 2. Theoretical sress concentration fator is 1.42 and notch sensitivity is 0.9.Assume the following ultimate stress = SSOMPa, yeld stress ~ 470MPa Endurance limit *275MPa, size factor = 0.88 and surface finish factor (10 Marks) 5 Define a lon, proftond un lood fcr Fxplin the loads ating on (ontaris) (10 Marks) b, Derivese 2 a equations for steady pull out and banked turn maneuver. Lof23 ‘ 18Al oe clined Asm srbatic irra hat reaches deign diving pega 185m ina dive eine ere ie porizontal ground. Ifthe maximum maneuyehiaad factor for the aire is Ra snc the height at which the pullout from the gi’ must being fon sight htt b achioved ate eight of SODm. Also daub ight path wit all te Gta, rial for aireraft sable proper w be consol when sleing ones (10 Marks) Discuss the Module-4 Derive the equations of equilibrium.on athree dimensional body. ao Marks) {A point in a strained member is subjected to. biaxial stresses, 85MPa (tensile along * 640) and 60MPa (compressive along’y. xis). The point is also subjected 10 a shear stress 4SMPa ttch that shear force on vertical faces give rise to clockwise couple. Determine ‘Stress acting on a plane “whose normal is at an arigle of 40° with reference to i 35 MPa stress direction fi) Magnitudes of pritapal stress and maximum aninimam shear stresses iit) Orientations ofthe principal planes and maximum snd minimum shear stress planes. ow What ag(titically determinate and jndetaginae structures? Give suitable examples with sketches 7 Marks) CCaledita the reactions at the support for tHe beam showin Fig.Q8(b) using Clayperon’s three moment theorem, Fig.Q8(b) wom Module-5 ‘State and prove Maxwell's tetiprocal theory. (ao starks) ‘A simply supported beam of span length {has an overhang of length ‘a’ on the left. The Vertical load “w" is applied atthe end of the overhang. Calculate the deflection cf the point ‘application of the oad by Castiglione’s frst theorem, (do Marks) or Vat are the\gssumptions made in the Euler's column theory? Derive Euler’ crippling load forthe column with both ends hinged. (10 Marks) {A hollow column whose Outside diameter is 200mm and thickness of 20mm is 4.5m lon; and is fixed at both ends Calculate the sae load by Rankine formula using a factor of safety of 25, Find the ratio of Euler’s to Rankine's loads, Take E =, x 10°N/mm’, Rankine Constant = 1/1 600.and permissive compressive stress = $50 N/mm’ (ao Marks)x03 SGilells | ISAE Fifth Semester B.E, Degree Examination, Feb./Mar. 2022 Aircraft Structures - I Time: 3 his Max. Marks: 100 Note: Answer any FIVE full questions, choosing ONE full question from exch module. Modute-t Explain the following : i) Facto ii) Uniaxial stress ii) True st (10 Marks) A mild steel shat of $0mm diameter is to a bending moment of 2000N-m and Torque “T". Ifthe yield point ofthe s n is 200MPa. Find the maximum value of this torque without eausing yielding ofthe shal ing i) Maximum principal stress theo ii) Maximum shear sires the iit) Maximum distortion strain energy theor (10 Marks) oR Why failure theory is important is aireraft plain the failure of brittle and ductile materials (10 Marks) Explain atleast four different theories of failure in detail (10 Marks) Module Define fatigue. With neat sketch explain S-N diagran (10 Marks) What is endurance limit? Explain the important modify he endurance i (10 Marks) oR Define fluctuating stress, Explain the Goodman and Soderberg telatiorship with relevant sketches and equations. (10 Marks) A copper bar of 12mm diameter gets stretched by Imm under a steady load of 4kN. What stress would be produced in the bar by a weight SOON, the weight falls though SOmm before striking the collar rigid fixed to the lower end of the bar? Take Young's modulus for the bar material as 100GPa, (06 Marks) Definig stress concentration and explain the same (04 Marks) Module-3 Draw the V-n diagram and explain in detail (08 Marks) Explain load factor and different types of loads acts on the aircraft, (04 Marks) An aireraft having # weight of 250kN and a triangle under carriage lands at vertical Velocity of 3.7avs, such that the vertical and horizontal reactions on the main 1200KN and 400KN, respectively, at this instant, the nose whee! i shown in Fig QS(c). If the moment of inert ie 5.65 x 10°NS'mm. Determine the inertia forees on the aireraf, the time taken for its vertical Velocity to become zero and its angular velocity at this instant wheels are 1.0m from the ground a of the airerafl about its CC (05 Marks)a b. OR What are the desirable properties of materials for aircraft applications? (os Marks) Deseribe merits, demerits and applications of i) Aluminium allo ji) Stainle alloy iit) Titanium alloy iv) Composite material (12 Marks) Module-4 ive the equilibrium equations fora 3 - D siress system. (10 Marks) aluate the principal stesses and principal planes forthe state of stress shown in Fig.Q7(b) Bonen Fig Q7h) (06 Marks) Explain the strain ~ displacement relation (04 Marks) or Derive Clapeyron’s three moment equation (10 Marks) A king post truss of Sm span is loaded as shown in Fig.Q8(b). Find the forves in each member of the truss and tabulate the results Fiz Q8b) (Qo Marksy Modu State and derive Maxwell's reciprocal theorem, (Marks) State and derive Castigliano’s Vand IT theorem. 10 Marks) OR Write a short note on South-Well plot. fenana Derive Rankine’s formula for columns. aay ‘AT-Section 150mm % 120mm x 20mm is used as a strut of 4m long with hinged at its both fends Calculate the eripling load. if Young"s modulus for the material be 200GPa,(ax Marks): USN BE RE | ] Fifth Semester B.E. Degree Examination, July/August 2022 Aircraft Structures -I Time: 3 brs. Max. Marks: 100 Note: Answer any FIVE full questions, choosing ONE full question from each module. Modute- 1 a. Explain briefly about design considerations (0s Marks) Briefly explain about triaxial and biaxial state of stresses. (05 Marks) A point ina strained material if subjected to a tensile stress of 300 N/mm? and 300 N/mm? in two mutually perpendicular planes. Calculate the-normal, tangential, resultant stress and its obliquity on a plane making an angle of 30° with the axis of minar tensile stress. Also find the maximum shear stress (10 Marks) g OR ¢ 2 a. Explain the following § (i) ~~ Maximum shear stress theory. 5 (ii) Strain energy theory, 5 (ii), Maximum normal stress theory (iv) Distortion energy theory. (12 Marks) . b. Phe principal stresses at a point in an elastic material are 200 Nimm? (Tensile), 100 N/mm*(Tensile) and 50 N/mm*(Compressive). If the stress at the elastic limit in simple tension is 200 N/mm?, determine whether the failure of the materia} will ogeyr according to: (i) Maximum Principal strain theory (ii) Maximum stress theory, (iii), Maximum strain energy theory. (iv) Maximum shear strain energy theory. Take Poisson’s ratio as 0.3. (08 Marks) Module-2 3° Derive an expression for impact factor due to axial load (10 Marks) ‘A Cantilever beam of width 50 mm, depth of 150 mm is 1.5 m long. [tis stuck by a weight of 1000.N that falls from a height of 10 mm at its free end, Peyermine impact factor, instantaneous maximum deflection, maximum shear and maximum load. (10 Marks) ” OR “Goodman relationship, (10 Marks) the S-N diagram got by the results of fatigue tes. (10 Marks) 1of2velocity of 3.7 1200 kN and O'NS’ List out the desirab Explain about metallic Module-4 Derive the equi ations. fo condition At a particular point in at 1 men 9, =-40 Ninim? and N/mm? IPE calculate the dicect strain in the x and caleulate principal strain at the pe oR Derive Clapeyto: ment equati Explain 1 steps involved in the an Modules State and explain Maxivell’s Reciprocal t State and prove Castigliano’ OR Detive an expression fr crippling load end is free A2m E=12 GP support the crippling k and allow ber a 20) stress system exists where is 1.0 m from ovary 3-D clastic material and reduse to 2-D plane st y* N/mm? and Poisson's ratio = 0. and the shear strain at the point. Also, aod their inclination 16 the plane on Which cy, acts, bjected 19 a load system. (0 Marks) ne end is fixed and the othe (12 Marks) ction to be made of wood assumin MPa, determine the size of column t ) 200 KN. Use FOS as 3 and—— 18AES3 uss ye | fs 8 Fifth Semester B.E, Degree Examination, July/August 2021 Aircraft Structures -! Max. Marks: 100 Note: Answer any FIVE full questions. Explain stress tensor and stress concentration factor (05 Marks) Body subjected to tensile stress of JOOMPa and 70MPa along two mutually perpendicular directions. The point is also subyeeted to shear stress of SOMPa. Determine: i) Normal and shear stfessjet plane inclined at 120° with reference to 100MPa stress plane ii) Principle and maaimim, minimum shear stress iii) Principle plane grigntation iv) Normal stress'6n planes of maximum and thinimum shear stress (15 Marks) Explain various methods by which stress goncentration can be reduced with sketches. (05 Marks) A point aiplate is subjected to a horizontal tensile stress of 100N/mm’ and vertical stress oF 6ON/mit?, Find the magnitude of principle stresses. (15 Marks) What is impact stress? (05 Marks) A steel rod is 1.5m long, is to resist impact load of 2.5KN falling under gravity at a velocity of 0.99mvsee maximurg cOmputed stress is lifted to 150MPa. Determine: i) Diameter of rod ii) Impact factor given E = 206.8 x 10°Nimmr (15 Marks) Explain Soderbeég and Goodman lines with neat graph. 7 (0S Marks) A circular bar of S00mm length is Supported freely at its two ends. It is acted upon by a central concentiaited cyclic load haVing minimum valué of 20kN and maximum value of SOKN. Determine diameter of bar taking FOS = |,5ysize effect of 0.85, surface finish factor of 0.9, ‘stress concentrator-factor of I. c, = 6S0MPa, o, = S00MPa and Endurance strength = 350MPa (1S Marks) ‘With neat skeich explain V-N diagrams (velocity load factory” (0S Marks) An aircraft having weight of ar lands with sink rate of 3.7m’see such that vertical and horizontal reactions on wheel are 1200kN and 400kN. Where nose wheel is Im ffom ground. I=5.65 x 10° Nis’ mm. Determine inertia force on aircraf time taken for its vertical velocity to become zero and its angular velocity at this instant y (1S Marks) 1 Onctors ‘What are the types of titahitim used in aircraft and give their properties? (10 Marks) Derive Griffith theory oferack growth on brittle material (10 Marks) Iraportan No Define plane stress, plane strain and principle stress, (10 Marks) Derive equations of equilibrium for the stress acting on a 3D clement ofan elastic material (10 Marks)SAE ninate structurés'give examples? (10 Marks) What are statistically determinate and indete (oMtarks) Prove Clapeyron’s theorem of three moments. (10 Marks) ‘State and prove Castigliano’s frst theorem in beam Silbjected to load systems. ‘A cantilever of length ‘L’ carries UDL of W/unitdength over whole span. Assuming uniform flexural rigidity, find strain energy stored and deflection at free end. (10 Marks) Derive an equation for critical buckling load of a column with the end eondition one fixed and other free (10 Marks) A 2 meter long pin ended column of square cross section of wood, Raving E = 12GPa, and allowable shear stress 12MPa is subjected to a load of 96KN. Determine the size of the column, Use FOS = 3, and use Euleperippling load for buckling, (10 Marks)aes Sarah vs [TTT TL) Fifth Semester B.E. Degree Examination, Jan/Feb. 2021 Aircraft Structures - 1 Time: 3 hrs. Max. Marks: 100 Note: Answer any FIVE full questions, choosing ONE full question from each module, Module-1 Explain the following, i) Principal stress ii) Plane stres iii) _ Stress Tensor (06 Marks) ‘\ point in a structural member subjected to a planéstress is shown in Fig.Q.1(b). Determine the following: i) Normal afd Tangential stress intensities on plane MN inclined at an angle 45° ii) Principalstfesses and their directions, ji) Maxinnim shear stress and direction of planes on which it occurs. mylene 1. yee Pots ft wll be weated as malpractice err the remain ® aueee Y \ as creel spent Fig. Q.1(b) 2 a a ily draw diagonal eras ines (14 Marks) OR ppe Explain the’following failure theories i) “Maximum normal stresstheory i)» Maximum shear stress theory fii), Maximum strain theory iv) _ Distortion enéfgy theory. (16 Marks) Explain the failuge’ofbrittle and ductile’material (04 Marks) ‘Module-2 Derive thé equation for instantanéOus stress due to axial impact on bars. (12 Marks) ‘A cantilever beam of span-800mm has a rectangular cross section of depth 200mm, The free ‘end of the beam is subjected to a transverse load of IKN that drops t, it from a height of 40mm. Where o, = 328MPa. Factor of safety is 3, determine the width of rectangular cross section (08 Marks) Qo! ing your answ Important No OR Explain with a heat sketch SN diagram and endurance limit. (10 Marks) Derive the equation for Soderberg relationship, (10 Marks) 1of218AE Explain the types of loads acting on aircraft and v-n diagram, (10 Marks) a total weight of 45KN lands on the dele of an aircraf! carrier and is ns of a cable engaged by an arrestar bok, as shown i Fig..5(b). if the deceleration induced by the cable is 5g determine-the tension T in the cable, the load on an undercarriage struct and the shear and axial loads jm the fuselage at the section AAA; The ‘weight of the aircraft afl of AA is 4.5KN. Caleulafe-also the length of deck covered by the aircraft before it is bought to rest ifthe touch daw'speed is 25's. (a0 Marks) Fig .5(b) oR Explain about metalic ail ponmetallic materials used rs (a0 Marks) Discuss the importance 6f composite materials. in wiry and enumerste advantages and disadvaftages of composite (10 Marks) Modulend 1 equilibrium equation. (a0 Marks) ment field u = fyi + 3yz) x 0°, Determine the mponents atthe point P(1, 0 (10 Marks) OR Differentiate between determitiant and indeterminabtstructur (06 Marks) Find the for (a4 Marks) Derive the equation for stFait eneray due to axial and bending (08 Marks) State and prave Maxwell reciprocal theorem (08 Marks) ‘An axial pull of SOKN is suddenly applied to a steel bar 2m long and 1000mm" in cross Section if E = 200kN/mm? find maximam instantaneous stress and maximum instantaneous extension. (04 Marks) OR Derive Rankine formula of a column. (08 Marks) Enumerate the Fulers theory assumptions (04 Marks) Find the Euler’s crippling load for a hollow cylindrical steel column of 40mm external diameter and 4mm thick The length of column is 25m and is hinged at both ends, also ‘compute the Rankines crippling load using constants 335MPa and 1/7500 take E = 205GPa, (08 Marks)