Fastening Elements for the Aerospace Sector

Quality and Safety Standards in Aerospace Fasteners

Safety and innovation are the two keywords in the aerospace industry.
To ensure high levels of performance and safety in the construction and use of various devices, it is necessary to use specific fasteners with well-defined characteristics.

In detail, the primary reference is to fastening elements, aeronautical components that play a fundamental role in design as much as in production.
Indeed, aerospace equipment and tools require secure and permanent joints because they are subject to extreme external factors such as:

• High pressure;
  
  
• Velocity;
  
  
• Wind;
  
  
• Unstable temperatures.

These are specific atmospheric conditions and environments, and therefore, the fasteners used must also meet equally specific characteristics. Among these:

• High resistance to oxidation and corrosion to withstand extreme temperatures and pressures;
  
  
• High shear and tensile strength to ensure long-term robustness;
  
  
• Lightweight structure to facilitate takeoff and reduce fuel consumption and related costs;
  
  
• Self-sealing and self-locking capabilities to avoid any type of pressure.

These listed are essential characteristics that fasteners used in this particular sector must meet. Only in this way can the standards of quality and safety be maintained over time.

Advanced Materials for Aerospace Fasteners

To maintain and ensure the criteria mentioned in the previous paragraph, the materials with which aerospace and aeronautical fasteners are made are also fundamental.

Generally, such components are found in:

• Aluminum, a material that resists extreme temperatures and corrosion even under high-stress conditions;
  
  
• Steel, a material characterized by high resistance and surface hardness. Since it is heavier than other materials, its application requires study and analysis for each specific project;
  
  
• Titanium, a valid alternative to aluminum, is a material that meets criteria of resistance and durability.

Its main advantage is the ability to withstand extreme temperatures, both hot and cold, in the long term. The choice of one material over another is to be made based on each device to be designed and realized.
The goal is to improve energy efficiency and therefore fuel consumption in every new project.

Design and Engineering of Bolts for Critical Loads

As highlighted in the previous paragraphs, to achieve the objectives of safety and quality of each device, it is crucial to study, analyze, and create projects that adapt to specific situations.
In this sense, an important role is therefore played by design to drawing, which, if entrusted and realized by specific suppliers equipped with ad hoc laboratories and machinery, will return the best solutions every time.

The steps of the design to drawing

The study and realization of a device and related fastening elements require the following distinct steps:

• Application analysis: the first step is to be carried out in close contact with the client to study the various technical characteristics of the application such as materials, structuring, geographical location, climatic conditions, any complications in installation, etc.
  
  
• Verification of hypotheses: the second step involves formulating some hypothetical solutions based on the problems to be faced. These can be advanced on the materials of an existing product, on the shape, on accessory characteristics, or on completely new drawing fasteners. Once the ideal solutions are evaluated, proceed with verifying them on parameters such as reproducibility, measurability, performance, etc.
  
  
• 3D drawings and video animation: once the actual possibility of realizing the product is established, faithful reproductions in 3D and animations can be made, to then proceed with the actual production;
  
  
• Prototyping and testing: in this phase, sampling batches are produced, a step that allows testing in the laboratory and, possibly, bringing the imagined solution to the construction site. Tests on a new generation product concern the technical sphere (resilience, traction, hold to unbuttoning) but also the usability sphere (ease of installation), the convenience on the construction site (possible packaging), and all accessory aspects that can contribute to turning a good technical solution into an excellent product.
  
  
• Production and supply: If the product passes every phase and meets the initial needs of the client, it moves to the final step and is ready for production and supply.

Fasteners in the Assembly of Aerospace Structures

Tested and certified fastening elements guarantee quality and safety.
In general, there are various types of tests, more or less specific, to subject the various fastening elements to, such as:

• Chemical analysis;
  
  
• Metallographic analysis;
  
  
• Tensile test;
  
  
• Fatigue test.

As for the possible certificates to request from manufacturers and suppliers of fasteners, we remember:

• Product specification;
  
  
• Test report type 2.2 UNI EN 10204;
  
  
• Inspection certificate type 3.1 UNI EN 10204;
  
  
• CE conformity declaration.

Such procedures and certifications serve to guarantee the maximum reliability of aeronautical and aerospace fastening elements.

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