6.4 hollow sleeve combined

7/27/2019 6.4 Hollow Sleeve Combined

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AAR Pylon to Wingbox Forward Attachments

Forward Attachments PAGE

Section 6.4.3 - Hollow Sleeve 6.4.50RF

6.4.3 Hollow Sleeve Combined Stresses

6.4.3.1 Introduction

The Hollow Sleeve (M57450115) is analysed for a combination of tensile, bending and shear loads

resulting from the application of loads to the lugs of the External Bracket from the AAR Pod.

The External Bracket is attached to the Internal Bracket by 8 special bolt-in-bolt fasteners,

clamping the Lower Cover and Interface Plate between them. The fasteners consist of the Hollow

Sleeve, with an External Bolt (9B) threaded in its internal threads, and a 10B Nut on its upper end.

Figure 6.4.3-1: AAR Pod Fwd Attachments - General view

Figure 6.4.3-2: AAR Pod Fwd Attachments - Front View

SUBJECT:FILE NO. A400M/TWEOM1E3/D/57-45-046

AUTHOR DATE

H Mir Dec-10

Internal Bracket

Internal Locking Sleeve

External Bracket

Inner Front Spar Web

O/B

I/B

Interface Plate

Spigots

Lower Cover(missing)

Special Fastener

(Hollow Sleeve)

External Bolt

O/BI/B

A

A


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Figure 6.4.3-3: Section A-A through AAR Pod Bolt-in-Bolt Fastener

As the Interface Plate has two spigots engaged in the External Bracket, and a radial clearance

exists between the External Bolt and External Bracket, all shear loads from the POD are assumed to be

transmitted into the lower part of the Hollow Sleeves at the point they contact the Interface Plate.

The tensile loads from the POD are reacted through the External Bolts into the internal threads of

the Hollow Sleeve.

The method of analysis for the Hollow Sleeve can be found in Ref. [16]

6.4.3.2 Applied Loading

Loadcase

Type

Maximum

Axial Load

(N) Bolt No.

Subcase

No.

Page

Reference

Intact 94870 3 4 5.5.3-1

Crash 141209 3 19 5.5.3-2

MLP 107371 3 3 5.5.3-3

Table 6.4.3-1: Maximum Tension Bolt - Axial Interface Loads

MaximumLoadcase Resultant Bolt Loadcase Page

Type Load No. No. Reference

Fr

[N]

Intact 35800 1 455 5.5.2-4

Crash 63526 1 19 6.2-11

MLP 27778 1 606 5.5.2-6

Table 6.4.3-2: Maximum Shear-out Loads


AUTHOR DATE

H Mir Dec-10

Nut

Anti-Rotation Sleeve

Anti-Rotation Plate

Internal Bracket

Lower Cover

Interface Plate

External Bracket

Internal Structure

External Structure

External Bolt

tint

text

t'int

Hollow Sleeve


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6.4.3.3 Analysis Method

Figure 6.4.3-4: Distribution of Shear Loads in Hollow Sleeve (No Moment) - Ref. [16], Figure 4

Figure 6.4.3-5: Distribution of Shear Loads in Hollow Sleeve (Full Moment) - Ref. [16], Figure 5


AUTHOR DATE

H Mir Dec-10

tint

tint_plate

tskin

tint_brk

Lint

Lint

textSapp

R1

R2

1

2 3

4

5

6

The analysis methods used are detailed in Ref [49]. There are two basic methods:

1. No Moment restraint from Nut - schematic shown in Figure 6.4.3-42. Full Moment restraint from Nut - schematic shown in figure 6.4.3-5

a) DistributedLoads

b) Equivalent Pointc) Shear Force

Diagram

d) BendingMoment

tint

tint_plate

tskin

tint_brk

Lint

Lth

textSapp

R1 1

2

4

M1 M1

3

a) Distributed b) Equivalent Point

c) Shear Force

Diagram d) BendingMoment


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6.4.3.1 Geometry

Internal bracket flange thickness tint_brk = 15.0 mm Ref. Page 3.1-6

Cover thickness tskin = 7.0 mm Ref. 4.11-1

Interface plate thickness tint_plate = 5.2 mm Ref. Page 3.2-2

Hollow sleeve outside dia Dint = 20.6 mm Ref. Page 3.5-1

Hollow sleeve inside dia D'int = 14.7 mm Ref. Page 3.5-1

Min major dia of external thread Ds_min = 15.9 mm Ref. Page 3.5-1

Min minor dia of external thread Ks_min = 14.7 mm Ref. Page 3.5-1

Diameter at undercut Dund = 13.9 mm Ref. Page 3.5-1

Load bearing length = MIN[Dint,(tint_brk+tskin)/4] = Lint = 5.5 mm Ref [16]

Internal structure thickness = tint_brk+tskin+tint_plate = t'int = 27.2 mm Ref [16]

6.4.3.4 Material data

Hollow Sleeve Inconel Alloy 718 AIMS 02-002-002 / AMS 5962 / AMS 5662

Stress KDF Resultant allowable

Ftu 1510 0.99 1495 MPa

Fty 1034 0.99 1024 MPa

Fsu 786 0.99 778 MPa

E 203 0.97 197 GPa

G 79 0.97 77 GPa

v 0.29

Table 6.4.3-3: Hollow Sleeve Material Data - Ref Section 4.3

6.4.3.5 Applied Loads

Sapp = 63526 N Ref. p. 6.2-11

Papp = 141209 N Ref [27], Table 5.2.2-3

Ref. [49]

Ref. [49]


AUTHOR DATE

H Mir Dec-10

intint_'int

intint_

2

intint_'int

intint_'int

1

3

232

3

232

Ltt

Lt

SR

Ltt

Ltt

SR

pla te

pla te

app

pla te

pla te

app


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6.4.3.5.1 Method 1 - No Moment Restraint from Nut

Using the Applied Loads in Section 6.4.3.5, the following values can be evaluated to correspond with

Figure 6.4.3-4.

Reaction Force 1 R1 = 78888 N Ref. [49]

Reaction Force 2 R2 = 15362 N Ref. [49]

Shear Force 3-4 SF34 = 63526 N

Shear Force 1-2 SF12 = 15362 N

Bending Moment 6 = Sapp x(tint_plate/2 + Lint BM6 = 281632 Nmm

Bending Moment 5 = R2 x 2 x (L int/3) BM5 = 56326 Nmm

Max. Shear Force Plain Tubular Section Smax_pl= 63526 N Ref. [16]

Max. Shear Force Internal Thread Smax_ithr= 15362 N Ref. [16]

Max. Shear Force External Thread Smax_xthr= 0 N Ref. [16]

Max. Bending Moment Plain Tubular Section Mmax_pl= 281632 Nmm Ref. [16]

Max. Bending Moment Internal Thread Mmax_ithr= 56326 Nmm Ref. [16]Max. Bending Moment External Thread Mmax_xthr= 0 Nmm Ref. [16]

Tensile Loading

Tensile load Plain Tubular Section Pmax_pl= 0 N

Tensile load Force Internal Thread Pmax_ithr= 141209 N

Tensile load External Thread Pmax_xthr= 141209 N

Stresses

Shear Plain Tubular Section tpl= 389 MPa

Shear Internal Thread tithr= 114 MPa

Shear External Thread txthr= 0 MPa

Bending/Axial combined Plain Tubular Sectio spl= 444 MPa

Bending/Axial combined Internal Thread sithr= 954 MPa

Bending/Axial Combined External Thread sxthr= 933 MPa

von Mises Plain Tubular Section svm_pl= 808 MPa

von Mises Internal Thread svm_ithr= 975 MPa

von Mises External Thread svm_xthr= 933 MPa

RFs

Reserve Factor Plain Tubular Section RFmax_pl= 1.85

Reserve Factor Internal Thread RFmax_ithr= 1.53

Reserve Factor External Thread RFmax_xthr= 1.60


AUTHOR DATE

H Mir Dec-10


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Stresses

Shear Plain Tubular Section tpl= 389 MPa

Shear Internal Thread tithr= 0 MPa

Shear External Thread txthr= 0 MPa

Bending/Axial combined Plain Tubular Sectio spl= 585 MPa

Bending/Axial combined Internal Thread sithr= 1450 MPa

Bending/Axial Combined External Thread sxthr= 2158 MPa

von Mises Plain Tubular Section svm_pl= 893 MPa

von Mises Internal Thread svm_ithr= 1450 MPa

von Mises External Thread svm_xthr= 2158 MPa

RFs

Reserve Factor Plain Tubular Section RFmax_pl= 1.67

Reserve Factor Internal Thread RFmax_ithr= 1.03


As the calculated RF for the external thread is low, the Airbus Collection Program ABS116 is used

to account for plasticity. The program calculates inelastic bending moments and end loads for

beam sections of general polygon shape. As the material characteristics Fn and m are required for

input to ABS116, the Airbus Collection Program AMP102 is run first to calculate them.

For input to AMP102, 2 reference stresses and associated strains are required. From Section 4,

the following material properties are defined:

Ftu (MPa) Elongatio Fty (MPa)

AIMS 1350 0.12 1100

AMS 1275 0.12 1034

However, drawing M57450115 specifies heat treat to 220 ksi (1510MPa). As there is no associatedvalue for Fty given, the values from the AIMS and AMS specs are factored by the ratio of Ftu values.

AIMS

AMS

The material Youngs Modulus = 203000 MPa

The associated strain at the heat treated Ftu of 1510MPa 0.007

As the material specifications specify 12% elongation, the proof strain at failur 0.113

The AMP102 inputs are therefore:

E 203000 MPa_1 0.113

_1 1510 MPa

_2 0.002

_2 1225 MPa

The AMP102 output gives: Fn 1107 MPa

m 19.29

The full AMP102 output is shown in Section 7.

Factored Fty (MPa)

1230

1225


AUTHOR DATE

H Mir Dec-10


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As well as the material data, the ABS116 input requires the vertices of the polygon shape to be

analysed. As the shape to be analysed is circular, a coordinate every 15 degrees has be chosen.

Dund = 13.9 mm Ref. Page 6.4-53

Angle X Coord Y Coord

0 6.94 0.00

15 6.70 1.80

30 6.01 3.47

45 4.91 4.91

60 3.47 6.01

75 1.80 6.70

90 0.00 6.94

105 -1.80 6.70

120 -3.47 6.01

135 -4.91 4.91

150 -6.01 3.47165 -6.70 1.80

180 -6.94 0.00

195 -6.70 -1.80

210 -6.01 -3.47

225 -4.91 -4.91

240 -3.47 -6.01

255 -1.80 -6.70

270 0.00 -6.94

285 1.80 -6.70

300 3.47 -6.01

315 4.91 -4.91

330 6.01 -3.47

345 6.70 -1.80

The applied End Load Pmax_xthr= 164168 N p6.4-54

The applied Moment Mmax_xthr= 281632 Nmm p6.4-54

The output from ABS116 is only valid for specific combinations of end load and moment.

The full ABS116 output is shown in Section 7.

From the ABS116 ouput, the allowable moment including plasticity e 278536 Nmm

RFs


Therefore RFmax_xthr= 1.0


AUTHOR DATE

H Mir Dec-10

Method 2 analysis, assuming that there is no support through the stack, is extremely conservative

especially when the sleeve is bending and has gone plastic. In this condition the cover will provide

some support. The low RF is also for the crash case only and failure through this section would not

lead to the failure of the whole system leading to rupture of the fuel tank.

6.4 hollow sleeve combined

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