Riveted Joints: Types, Related Terms, Causes of Failure

Hello, friends today I am going to talk about riveted joints in which you will be aware of all aspects related to riveted joints such as types of riveted joints, related terms, various causes of failure, etc.

What is Rivet?

A rivet serves as a semi-permanent fastening device used for joining sheets. Comprising three main parts – Head, Shank or Body, and Tail – a rivet is a circular metal rod. Typically constructed from soft metals like copper or brass, the process of securing a rivet in a hole and spreading the end of its tail is known as riveting. Riveting is accomplished by applying pressure to the rivet’s head using hydraulic pressure, pneumatic pressure, or a hammer.

What is Riveted Joint?

The process of connecting metal sheets or plates using rivets is referred to as a riveted joint.

Types of Riveted Joints

Mainly two types of joints are used while joining metal sheets by rivets: 
  • Lap Joint
  • Butt Joint
See in the figure types of riveted joints which are described below in detail.
Riveted Joints Types, Related Terms, Causes of Failure
Riveted Joints Types, Related Terms, Causes of Failure

 

Lap Joint

A lap joint is formed when the edges of two sheets or plates are positioned above or below each other and joined using rivets. This type of joint is created by inserting a rivet through the overlapping sections and securing it to connect the sheets. The rivets are typically applied in a pattern along the length of the joint, ensuring a secure connection. Lap joints are commonly used in various applications to join metal components in structures and other assemblies.

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Lap joint can be divided into the following types:
  • Single Row Lap Joint
  • Double Row Lap Joint
  • Chain Lap Joint
  • Zig Zag Lap Joint
See in the figure different types of lap joints which are described below in detail.
Types of Lap Joint
Types of Lap Joint

 

Single Row Lap Joint

A single row lap joint is formed when a line of rivets is used to connect the overlapping edges of two sheets or plates. In this type of joint, a row of rivets is applied along the length of the overlap, securing the sheets together. The rivets play a crucial role in holding the joint in place and ensuring the stability of the connected components. Single row lap joints are a common configuration in riveted assemblies, providing strength and durability to the joined materials.

Double Row Lap Joint

A double row lap joint is created when two lines of rivets are employed to connect the overlapping edges of two sheets or plates. In this configuration, rivets are applied along two parallel rows, securing the sheets together. The use of two rows of rivets enhances the strength and stability of the lap joint, making it a robust and reliable method for joining materials. Double row lap joints are commonly employed in riveted assemblies where increased structural integrity is desired.

Chain Lap Joint

A chain lap joint is formed when multiple lines of rivets are utilized to connect the overlapping edges of two sheets or plates. In this setup, rivets are arranged in a series of rows, resembling a chain, to secure the sheets together. This design offers additional reinforcement and distributes the load across multiple rows of rivets, contributing to the overall strength and stability of the joint. Chain lap joints are employed in situations where enhanced structural support and durability are essential, providing a reliable method for joining materials in various applications.

Zig-Zag Lap Joint

A zig-zag lap joint is established when two or more lines of rivets are employed in a lap joint, arranged in a zig-zag pattern. In this configuration, the rivets are strategically placed in a back-and-forth manner along the overlapping edges of the sheets or plates being joined. This zig-zag arrangement enhances the structural integrity of the lap joint by providing a more secure and evenly distributed connection. Zig-zag lap joints are utilized when increased strength and stability are required in applications where conventional lap joints may not provide sufficient support.

Butt Joint

In this method, the ends of the sheets or plates are connected by placing a separate piece of sheet on top of them. This additional piece of sheet is referred to as a strap. The strap effectively covers and secures the joint by encompassing the connected ends, providing reinforcement and additional support to the overall structure. This type of joint, utilizing a strap, is employed in scenarios where extra strength and durability are required, ensuring a robust and reliable connection between the sheets or plates.

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In this, two sheets or plates touch each other but do not overlap.
The butt joint can be divided into the following types:
  • Single Row Single Strap Butt Joint
  • Single Row Double Strap Butt Joint
  • Double Row Double Strap Butt Joint
See in the figure different types of butt joints which are described below in detail.
Types of Butt Joint
Types of Butt Joint

 

Single Row Single Strap Butt Joint

In this configuration, a single row of rivets and a single strap are utilized on both sheets intended for joining. This assembly is known as a single row single strap butt joint. The rivets and strap work in tandem to secure and connect the two sheets, forming a robust butt joint. This type of joint is employed when a straightforward yet sturdy connection is required between the sheets, and the use of a single row of rivets and a single strap suffices for the intended application.

Single Row Double Strap Butt Joint

In this scenario, when one row of rivets is paired with two straps, utilized on both sheets to be joined, it is termed a single row double strap butt joint. This type of butt joint involves the incorporation of a single row of rivets along with two separate straps, strategically placed on either side of the joint. The combination of rivets and double straps enhances the strength and stability of the joint, providing a reliable connection between the sheets. This configuration is employed when additional reinforcement and load-bearing capacity are necessary for the specific application.

Double Row Double Strap Butt Joint

In the case where two rows of rivets are accompanied by two straps, utilized on both sheets to be joined, it is denoted as a double row double strap butt joint. This type of butt joint involves the incorporation of two parallel rows of rivets along with two separate straps, strategically positioned on either side of the joint. The inclusion of double rows of rivets and straps enhances the overall strength and stability of the joint, making it well-suited for applications requiring increased load-bearing capacity and robust connections between the sheets. This configuration is employed when the joint demands additional reinforcement and structural integrity.

Terms Related to Riveted Joint

There are the following terms related to riveted joints:
  • Pitch
  • Diagonal Pitch
  • Back Pitch
  • Margin

Pitch

It refers to the center-to-center spacing between two consecutive rivets in the same row, measured parallel to the seam or edge of the plate. This dimension is crucial in determining the distribution of rivets along the joint, influencing the overall strength and stability of the connection. The closer the rivet spacing, the more uniformly the load is distributed, contributing to enhanced structural integrity and load-bearing capacity. Proper spacing is a critical aspect of rivet placement, ensuring optimal performance and durability of the riveted joint.

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Usually, 
Pitch = 3 x the diameter of the rivet hole or rivet after riveting.  

Diagonal Pitch

It represents the transverse distance between the centers of rivets in parallel rows on the same plate. This measurement is essential for determining the spacing and arrangement of rivets across the width of the plate. Proper staggered spacing ensures an effective load distribution, contributing to the overall strength and stability of the riveted joint. The careful consideration of this dimension is crucial in achieving a well-balanced and robust connection between the sheets or plates in the structure.

Back Pitch

It signifies the parallel distance between rows of rivets along the seam or edge of the plate. This measurement is critical for establishing the layout and alignment of rivets in relation to the plate’s longitudinal axis. Proper spacing between rows contributes to the structural integrity and load-bearing capacity of the riveted joint. Accurate placement ensures the effective distribution of forces and enhances the overall stability of the joined sheets or plates.

Margin 

This is the minimum distance from the center of the rivet hole to the nearest edge of the plate.

It is usually kept equal to 1.5 x the diameter of the rivet hole.

Common Causes of Failure of Riveted Joint

Reasons for Failure Remedies
The diameter of the rivet of the plate thickness is too small, the diameter of the rivet must be greater than the thickness of the plate to which it is to be placed. Select the correct diameter of the rivet according to the thickness of the plate. 
The diameter of the rivet is much larger than the thickness of the plate.  Rivets have a tendency to crush the metal in front of them when they are driven. Select the correct diameter of the rivet according to the thickness of the plate.
Punch or drilled rivet holes too close to the edge of the plate.  A crack in the front of the rivet may cause the metal to fail.  Drill or punch the rivet holes at the correct distance from the edge and use the correct lap allowance for the diameter of the rivet chosen.  
Weakening of plates due to making rivet holes too close to each other.  The plates have a tendency to break along the center line of the rivets. Drill or punch the rivet holes to the correct spacing or pitch.  In addition, before the final assembly, clean all burrs, etc. from the holes.

 

In this discussion, I covered various types of riveted joints, terminologies associated with riveted joints, reasons for the failure of riveted joints, and potential remedies.

I hope you all enjoy this topic.

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