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At least 19 records

The Effect of Surface Irregularities on Wing Drag. I. Rivets and Spot Welds: Rivets and Spot Welds - 1

Tests have been conducted in the NACA 8-foot high-speed wind tunnel to determine the effect of exposed rivet heads and spot welds on wing drag. Most of the tests were made with an airfoil of 5-foot chord. The air speed was varied from 80 to 500 miles per hour and the lift coefficient from 0 to 0.30. The increases in the drag of the 5-foot airfoil varied from 6%, due to countersunk rivets, to 27%, due to 3/32-inch brazier-head rivets, with the rivets in a representative arrangement. The drag increases caused by protruding rivet heads were roughly proportional to the height of the heads. With the front row of rivets well forward, changes in spanwise pitch had negligible effects on drag unless the pitch was more than 2.5% of the chord. Data are presented for evaluating the drag reduction attained by removing rivets from the forward part of the wing surface; for example, it is shown that over 70% of the rivet drag is caused by the rivets on the forward 30% of the airfoil in a typical case.

Hood, Manley J.↗

Riveted assemblies and methods for riveting components

Riveted assemblies are provided that can include: a first component having opposing first and second sidewalls; a second component having opposing third and fourth sidewalls, wherein the second sidewall of the first component abuts the third sidewall of the second component to bind and form an affixing interface comprising the second and third sidewall between the first component to the second component; and a rivet extending between a head along a shank to an end, the rivet piercing the first sidewall with the end of the rivet being between the first and fourth sidewalls. Methods for affixing at least two components using a rivet are also provided. The methods can include: providing a first component having opposing first and second sidewalls; providing a second component having opposing third and fourth sidewalls; abutting the second sidewall of the first component to the third sidewall of the second component; providing a rivet extending between a head along a shank to an end; projecting the rivet through at least the first sidewall of the first component to form an affixing interface comprising the second and third sidewalls.

Joshi, Vineet V.↗

Riveted assemblies and methods for riveting components

Riveted assemblies are provided that can include: a first component having opposing first and second sidewalls; a second component having opposing third and fourth sidewalls, wherein the second sidewall of the first component abuts the third sidewall of the second component to bind and form an affixing interface comprising the second and third sidewall between the first component to the second component; and a rivet extending between a head along a shank to an end, the rivet piercing the first sidewall with the end of the rivet being between the first and fourth sidewalls. Methods for affixing at least two components using a rivet are also provided. The methods can include: providing a first component having opposing first and second sidewalls; providing a second component having opposing third and fourth sidewalls; abutting the second sidewall of the first component to the third sidewall of the second component; providing a rivet extending between a head along a shank to an end; projecting the rivet through at least the first sidewall of the first component to form an affixing interface comprising the second and third sidewalls.

Joshi, Vineet V.↗

Effect of Rivet Pitch upon the Fatigue Strength of Single-row Riveted Joints of 0.025- to 0.025-inch 24S-T Alclad

S-N curves at the range ratio of 0.2 were experimentally obtained for each of the following values of rivet pitch P as used in a single-row lap joint of 0.025- to 0.025-inch 24S-T alclad with one-eight AN430 round-head rivets: p=0.5, 0.75, 1.0, 1.5. Families of constant rivet pitch curves, which define the fatigue life for specimens studied, were developed. Curves showing the variation of the effective stress concentration factor in fatigue with rivet pitch and maximum load per rivet were also established.

Seliger, Victor↗

Friction-based riveting technique for AZ31 magnesium alloy

Rivet materials used in the aerospace and automotive industries are typically alloys of aluminum (Al) or steel. Magnesium (Mg) is an attractive alternative because it is 33% and 75% lighter than Al and steel, respectively. However, a primary barrier for using Mg as rivet material is its poor formability at room temperature, resulting in brittle fracture of the rivet head during cold riveting. Hot riveting is possible but suffers from high cycle time due to the need for pre-heating. A new friction-based riveting technique, Rotating Hammer Riveting (RHR), is reported to fully form AZ31 Mg rivet heads in a mere 0.23 seconds cycle time. Heat and pressure generated through severe plastic deformation during the process was sufficient to form the Mg rivet head without the need for a separate pre-heating operation. Due to dynamic recrystallization, AZ31 Mg grains in the rivet head were significantly refined from about 15 to 2.6 µm during RHR, which favors the formability of Mg rivet by triggering grain boundary sliding and reducing plastic anisotropy of Mg. In addition, RHR joints showed a metallurgical bond between the rivet head and top sheet, which eliminates a significant pathway for corrosion.

36 MATERIALS SCIENCE↗

A Flush-Rivet Milling Tool

The investigation of machine-countersunk flush rivets for aircraft described in reference 1 revealed the necessity of having the height of the rivet heads greater than the depth of the countersunk holes if tightly riveted joints were to be obtained. If ordinary roundhead rivets were inserted from the opposite side of the joint and the countersunk heads formed in the driving of the rivets filled the countersunk holes completely, still tighter joints were obtained. In either case the rivets protruded above the skin surface after driving, and the protruding portion of the rivet heads had to be removed in order to obtain flush rivets. A number of requests have been received for a description of the tool used to mill off the protruding portion of the rivet heads. This report contains assembly and detail drawings of the latest flush-rivet milling tool used at the NACA Structures Research Laboratory. Figure 6 shows the tool in operation. This tool is quite satisfactory for 1/8-inch rivets, but a more powerful motor is recommended for use with larger rivets.

Gottlieb, Robert↗

Assemblies, riveted assemblies, methods for affixing substrates, and methods for mixing materials to form a metallurgical bond

Riveted assemblies are provided that can include a substrate extending between two ends to define opposing substrate surfaces having a first opening extending between the opposing substrate surfaces; a metal-comprising substrate extending between two ends to define opposing metal-comprising substrate surfaces having a second opening extending between the opposing metal-comprising substrate surfaces. The riveted assemblies can further provide that the first and second openings complement one another when the substrate and metal-comprising substrate are engaged; and a rivet shaft extends through the openings and engages the substrate with the rivet head and the metal-comprising substrate with the rivet stop head, at least a portion of the stop head being mixed with, and forming a metallurgical bond with the metal-comprising substrate. Assemblies are provided that can include a rivet stop head mixed with, and metallurgically bonded with a metal-comprising substrate.Methods for affixing substrates to one another are also provided. The methods can include providing a substrate defining an opening configured to receive a rivet shaft; providing a metal-comprising substrate defining a complimentary opening; operatively engaging the substrates with the rivet shaft; and forming a stop head from the rivet shaft to affix the substrates. The method further includes that the stop head mixes with, and forms a metallurgical bond with the metal-comprising substrate. Methods for mixing materials to form a metallurgical bond are also provided. The methods can include forming a metallurgical bond between a stop head of a rivet and a metal-comprising substrate.

Whalen, Scott A.↗

Tensile Tests of NACA and Conventional Machine-countersunk Flush Rivets

An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets.

RIVETS, COUNTERSUNK - NACA↗