Tensile test failure velocity

In summary, during a tensile test on a threaded bar and nut, if the nut thread reaches failure and shoots off, the velocity and force it would hit a wall 20cm away can be calculated by integrating the stress strain diagram to find the total energy stored in the threaded bar. This energy is stored evenly along the bar and if the bar fails suddenly, the remaining elastic portion will accelerate towards the nut, carrying the mass of the bar and nut from the machine. The kinetic energy of the ejected mass will be slightly less than the potential energy stored as tension in that portion of the bar. The type of material used for the threaded rod and nut will determine the behavior of the failure, with ductile materials exhibiting slow creep and brittle materials
  • #1
BruceD
1
0
Hi, so when doing a tensile test let's say on a threaded bar and a nut. The nut thread reaches failure and shoots off. How would you calculate that velocity and the actual force that it would hit say a wall 20cm away. just for information the failure point was at about 300kN
 
  • #3
As tension is increased, almost all energy will be stored in the threaded bar and the elastic properties of the testing machine's framework. Very little energy will be stored as axial compression in the nut.
If the thread on the nut and/or bar strips due to tension, the failure will usually be a slow creep and not shoot-off fast. The stored energy is expected to go into deforming the contact material. The situation will be different with glass or metals that are not ductile.

Integrate the stress strain diagram to find the total energy stored in the threaded bar. That energy is stored evenly along the bar. If the bar then fails suddenly, the proportion of the length of elastic bar still attached to the nut will accelerate towards the nut, then carry the mass of the bar and nut from the machine. The kinetic energy of the ejected mass will be slightly less that the potential energy stored as tension in that part of the elastic rod.

What material is the threaded rod and nut ? Is it ductile or brittle ?
 

Related to Tensile test failure velocity

1. What is tensile test failure velocity?

Tensile test failure velocity is the speed at which a material fails or breaks under tension. It is an important measure of a material's strength and durability.

2. How is tensile test failure velocity measured?

Tensile test failure velocity is measured by subjecting a material to a tensile force until it breaks, and then calculating the velocity at which the failure occurred. This can be done using specialized equipment such as a tensile testing machine.

3. What factors can affect tensile test failure velocity?

Tensile test failure velocity can be affected by various factors, including the type and quality of the material, its temperature and environmental conditions, and the rate of loading during the test. Other factors may include manufacturing processes, defects, and material properties such as ductility and toughness.

4. Why is tensile test failure velocity important?

Tensile test failure velocity is an important measure in materials science and engineering as it provides valuable information about a material's strength, performance, and potential failure points. It can also help in the design and selection of materials for different applications, as well as in quality control and failure analysis.

5. How can knowledge of tensile test failure velocity be applied in real-world scenarios?

Understanding the tensile test failure velocity of a material can be applied in various real-world scenarios, such as in the development and testing of new materials for different industries, including aerospace, automotive, construction, and manufacturing. It can also be used in product design and material selection to ensure safety and reliability. Additionally, knowledge of tensile test failure velocity can aid in failure analysis and identifying potential areas of improvement in existing materials and structures.

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