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An Aerospace An Aerospace Manufacturing Manufacturing
PerspectivePerspective
Aerospace Fastener ApplicationsAerospace Fastener Applications
Part 2Part 2
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Aerospace Rivets
Primarily used to fasten aerospace skins to the sub-structure
Concerned mainly with shear and tension loads. Two types of rivets:
– Solid Rivet– Blind Rivet
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Aerospace Rivets
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• Rivets on the skin of a Boeing 737
Aerospace Solid Rivets
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Aerospace Solid Rivets
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• Universal solid rivets on the skin of a Boeing 737
•Note that they are not flush with the skin
Aerospace Solid Rivets
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• Countersunk solid rivets on the engine pylon of a Boeing 737
• Note that these rivets are flush with the surface
Aerospace Solid Rivets
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Aerospace Solid Rivets - Identification
Rivets manufactured in accordance with the AN/MS standards are identified by a four part code:
1. AN or MS specification and head type
2. one or two letters that indicate the material
3. shank diameter in 1/32nd inch increments
4. a dash followed by a number that indicates rivet length in 1/16th inch increments.
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Aerospace Solid Rivets - Identification
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• Aircraft rivets are made of many materials, and come in a wide variety of shapes and sizes
• How do you select the right size?
• How do you select the right material?
•We must know what the part number tells us…
Aerospace Solid Rivets - Identification
Example: rivet identification standard universal head solid rivet Material: 2117-T4 aluminium 1/8 inch diameter 5/16 inch in length Rivet ID = either AN470AD4-5 or MS20470AD4-5
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Aerospace Solid Rivets - Identification
Same rivet, different material:1100 aluminium – AN470A4-5 or MS20470A4-5.
AN470 or MS20470 denote the specification for universal head types AD is the material code for 2117-T4
– (A=1100, B=5056, C=copper, D=2017, DD=2024, F=stainless and M=Monel)
4 = 4/32 or 1/8 inch diameter -5 = 5/16 inch length
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Aerospace Solid Rivet Installation
Rivet installation summary– Drill appropriately sized holes– Deburr holes– Secure pieces together with Clecos– Install rivet, buck with rivet gun or use a rivet
squeezer
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Aerospace Solid Rivet Installation
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• .032” 2024-T6 sheet aluminum to be joined with rivets•Rivet gun•Bucking bar•Drill•Drill bit and chuck key•Center punch•Cleco•Cleco pliers
Aerospace Solid Rivet Installation
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• Drilling holes with a #30 drill bit
• Use 1/8” rivets with a #30 (.1285”) drill bit
Aerospace Solid Rivet Installation
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• Deburr the holes by rotating (by hand) a much larger drill bit in the holes
• This removes any metal shavings caused by drilling
Aerospace Solid Rivet Installation
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• Position the pieces together and secure using Clecos
•Clecos maintain proper alignment of the pieces while rivets are being installed
Aerospace Solid Rivet Installation
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• Place the rivet in the hole
• Make sure you are using the correct size, material, and type of rivet
Aerospace Solid Rivet Installation
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• Align the rivet gun on the rivet head
• Hold the bucking bar on the opposite end of the rivet
• Pull the trigger on the rivet gun to hammer the rivet in place
Aerospace Solid Rivet Installation
Solid rivets can be installed using a rivet squeezer instead of a pneumatic rivet gun
The squeezer is hand operated
The squeezer uses various inserts depending on the type and size of rivet being installed
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Aerospace Blind Rivets
Used when you cannot physically access one side of the work
Blind rivets are hollow, and thus weaker than solid rivets To retain strength of the joint:
– stronger material, larger diameter rivets, or more are necessary and of course
20–50% heavier than a solid rivet because of steel stem
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Aerospace Blind Rivets
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Aerospace Rivets – Fuselage Repair
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•Note that solid fasteners are used except in the middle of the patch
• Why would you use blind fasteners in this application?
• Exterior of a riveted patch fuselage skin patch
Aerospace Rivets – Fuselage Repair
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•Because the stringer on the interior of the fuselage prevents the bucking a solid rivet requires
• Blind rivets are the only option when access is restricted
• Interior of a riveted fuselage skin patch
Quality Assurance of Aerospace Fasteners
Aerospace Fasteners Material Selection
Aerospace Fasteners Testing
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Aerospace Fasteners Material Selection
Background Some factors to be considered before material selection
are: The max. and min. operating temperaturesThe corrosiveness of the environmentFatigue and impact loading
Always try to use standard fasteners, such as AN, MS, MIL, NAS, SAE
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Aerospace Fasteners Material Selection
Alloy Steels Aluminum Titanium Stainless Steel Superalloys
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Aerospace Fasteners Material Selection
Aluminum is the predominant material used in the manufacture of commercial aircraft.
Table 3 lists the typical aluminum alloys used in commercial aircraft.
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Basic Aerospace Fasteners Application
The basic applications (or needs) for aerospace fasteners are:– Shear – Tension– Fatigue– Fuel tightness– High temperature– Corrosion control
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Aerospace Fasteners Testing
Analyzing a Joint– Calculate all the load required for each type of
joint failure: Rivet Shear Sheet Tensile Bearing Sheet Shear
– Failure will occur in the mode that corresponds with the lowest load carrying capability.
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Aerospace Fastener Standardization
Most aerospace hardware is manufactured per government standards
The three most common aircraft fastener standards used are:– AN = Air Force/Navy– NAS = National Aerospace Standards– MS = Military Standards
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Common Standardized Fasteners
– Bolts– Nuts– Washers– Turnbuckles– Cotter pins– Screws– Rivets– Plumbing fittings (pipes and tubes)
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