Fastener Design Course Part -7 : Rivets | Lockbolts | Fasteners Tensile and Carbon Content Tests
Channel: Fasteners
Date: 2021-03-30

General Types of Rivets & Their Applications:
Rivets stand up to vibration better than normal screws. What differentiates a riveted joint from a bolted joint is that the rivet expands when bucked to completely fill the hole into which it has been installed.

Rivets are among the most common and useful fasteners in industry. They are used in a variety of applications, including automobiles, airplanes, machine tools, furniture, and construction. There are many different varieties, and the choice of rivet type depends on the specific application.

Types of Rivet Heads:
There are four basic types of rivets; tubular, blind, solid and split. 
Rivet heads are one of the few type of fasteners in which the head is actually a separate part that is attached to the shank of the fastener. This means that rivet heads are not usually interchangeable and there are a number of different types of rivet heads that are used in a variety of different applications.

Lockbolts:
lockbolt is a two-piece fastener that combines the features of a high strength bolt and a rivet with advantages over each.
Lockbolts have their own grip gauge and an installation tool is required for their installation. When installed, the lockbolt is rigidly and permanently locked in place. Three types of lockbolts are commonly used: pull-type, stump-type, and blind-type.

Tensile Test:
It is used to find out how strong a material is and also how much it can be stretched before it breaks. This test method is used to determine yield strength, ultimate tensile strength, ductility, strain hardening characteristics, Young's modulus and Poisson's ratio. Tensile strength, or ultimate tensile strength, measures a metal's resistance to breaking or pulling apart in two pieces. To find out how strong a wire is, one could just hang heavier and heavier weights on it until it breaks.

Carbon Content Test:
Total carbon content is determined in dried sediments and total organic carbon is determined in dried and acidified sediments using a LECO CR-412 Carbon Analyzer. Sediment is combusted in an oxygen atmosphere and any carbon present is converted to CO2.

Source: http://www.sti.nasa.gov​
https://www.youtube.com/channel/UCI9BX-UcPOhsfr0fTklLytQ

Richard T. Barrett, Senior Aerospace Engineer of NASA Lewis Research Center presents a comprehensive course on fastener design. A recognized expert in the field of fastener technology Mr. Barrett combines lecture, charts, illustrations with real-world experiences. Topics covered include: materials, plantings and coatings, locking methods threads, joint stiffness, rivets, inserts, nut plates, thread lubricants, design criteria, etc.

Fastener design is the process of using engineering principles to design fasteners for use in a product, system, or structure. One of the best ways to learn fasteners, in particular, is to sit down with an experienced practitioner and listen to him or her explain the ups and downs of their career. Richard T. Barrett is an aerospace engineer (aerospace engineer) at NASA Lewis Research Center in Cleveland. He has been involved in aerospace and rocketry for over forty years, including work on the Space Program, rocket engines, and launch pads. He is one of the world's experts on the subject of fasteners and fastener design.

Match drilling of fasteners holes:
Although proper match drilling can protect and enhance the appearance of a fastener hole, it still has limitations and is not always the best choice for all applications. This video discusses match drilling as a method of locating and creating the pilot hole in the work piece, as well as some of the issues that may arise during the process.

The first step is to drill a hole in the center of the fastener. This hole should be slightly larger than the diameter of the fastener. With the first hole drilled, the next step is to measure the exact distance between the top and bottom of the hole. (The distance between the bottom of the hole and the top of the fastener should be slightly larger than the thickness of the material you are drilling through.)

Dimpled and counter sunk holes:
Most fasteners, such as screws and nuts, have a head that is designed to fit a specific type of fastener recess. The recess is a dimple, counterbore, or counter-sunk hole that allows the nut to hold the screw or bolt firmly in place. The recess is threaded to match the fastener and is designed to prevent loosening in use. There are several different types of fasteners, and each type of fastener is used in specific applications. When selecting the correct fastener for a given application, there are many factors to consider, including the size, shape, and type of material to be fastened; the size and type of the hole in which the fastener will be installed; and the desired design of the finished product.

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