Aerospace Fastener Applications Part 2 An Aerospace Manufacturing Perspective

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

Aerospace Rivets Rivets on the skin of a Boeing 737

Aerospace Solid Rivets

Aerospace Solid Rivets Universal solid rivets on the skin of a Boeing 737 Note that they are not flush with the skin

Aerospace Solid Rivets Countersunk solid rivets on the engine pylon of a Boeing 737 Note that these rivets are flush with the surface

Aerospace Solid Rivets

Aerospace Solid Rivets - Identification Rivets manufactured in accordance with the AN/MS standards are identified by a four part code: AN or MS specification and head type one or two letters that indicate the material shank diameter in 1/32nd inch increments a dash followed by a number that indicates rivet length in 1/16th inch increments.

Aerospace Solid Rivets - Identification 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

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

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

Aerospace Solid Rivet Installation .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 Drilling holes with a #30 drill bit Use 1/8” rivets with a #30 (.1285”) drill bit

Aerospace Solid Rivet Installation 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 Position the pieces together and secure using Clecos Clecos maintain proper alignment of the pieces while rivets are being installed

Aerospace Solid Rivet Installation Place the rivet in the hole Make sure you are using the correct size, material, and type of rivet

Aerospace Solid Rivet Installation 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

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

Aerospace Blind Rivets

Aerospace Rivets – Fuselage Repair Exterior of a riveted patch fuselage skin patch Note that solid fasteners are used except in the middle of the patch Why would you use blind fasteners in this application?

Aerospace Rivets – Fuselage Repair Interior of a riveted fuselage skin patch 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

Quality Assurance of Aerospace Fasteners Aerospace Fasteners Material Selection Aerospace Fasteners Testing

Aerospace Fasteners Material Selection Background Some factors to be considered before material selection are: The max. and min. operating temperatures The corrosiveness of the environment Fatigue and impact loading Always try to use standard fasteners, such as AN, MS, MIL, NAS, SAE

Aerospace Fasteners Material Selection Alloy Steels Aluminum Titanium Stainless Steel Superalloys

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.

Basic Aerospace Fasteners Application The basic applications (or needs) for aerospace fasteners are: Shear Tension Fatigue Fuel tightness High temperature Corrosion control

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.

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

Common Standardized Fasteners Bolts Nuts Washers Turnbuckles Cotter pins Screws Rivets Plumbing fittings (pipes and tubes)