Failure analysis of a 2 OD solid 6063 aluminum round bar

In summary: Ok thanks for the assistance. I appreciate it.EMCSQ: That type of requirement is written such that the given load, P, already includes the ultimate factor of safety, dynamic amplification factor, and any fatigue factor. All you need to do is apply the given load, and ensure the bending stress does not exceed the material strength. When you perform an elastic analysis, you immediately see your bending stress exceeds the material tensile yield strength, Sty = 214 MPa. Therefore, you know the beam is yielding, and an inelastic analysis is required. To perform a simplistic plastic analysis, you can divide the elastic bending stress by an ultimate plastic shape factor, sf. In your particular case, sf = 1.822
  • #1
EMCSQ
2
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Failure analysis of a 2" OD solid 6063 aluminum round bar

I have a 6 foot piece of 2" OD solid 6063 aluminum bar that is supported at both ends. Hanging from the center is a 5000 pound weight. What techniques and equations would be used to determine if the aluminum bar will successfully bear this load?

This setup is going to be used as an anchor point for fall arrest protection on a communications tower.

Any help anyone can provide would be appreciated.
 
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  • #2


Well, the static case is quite simple. Easiest way would be to simple look up the load case in Roark. Find your max stress (should be at the center). Compare that to the strength of your material. Factor in your safety factor.

However, if the load is going to essentially be dropped onto it, then there are additional factors one needs to account for. I won't get into it in detail, but there are factors that you can use to account for sudden loading. There is a section also in Roark (while you're there) that gives the factors.

Make sure that you account for any possible decrease in strength in the material being that this is essentially used as human safety. Corrosion, heat, anything, PLUS use a beefy safety factor.
 
  • #3


minger said:
Well, the static case is quite simple. Easiest way would be to simple look up the load case in Roark. Find your max stress (should be at the center). Compare that to the strength of your material. Factor in your safety factor.

However, if the load is going to essentially be dropped onto it, then there are additional factors one needs to account for. I won't get into it in detail, but there are factors that you can use to account for sudden loading. There is a section also in Roark (while you're there) that gives the factors.

Make sure that you account for any possible decrease in strength in the material being that this is essentially used as human safety. Corrosion, heat, anything, PLUS use a beefy safety factor.

I agree with the advice minger gave and will stress the importance of accounting for the additional load due to the fall arrest requirement. Additionally, you might want to consider the fatigue life of it since it will probably be in service for a while based on the application.

CS
 
  • #4


Ok thanks for the assistance. I appreciate it.
 
  • #5
EMCSQ: That type of requirement is written such that the given load, P, already includes the ultimate factor of safety, dynamic amplification factor, and any fatigue factor. All you need to do is apply the given load, and ensure the bending stress does not exceed the material strength. When you perform an elastic analysis, you immediately see your bending stress exceeds the material tensile yield strength, Sty = 214 MPa. Therefore, you know the beam is yielding, and an inelastic analysis is required. To perform a simplistic plastic analysis, you can divide the elastic bending stress by an ultimate plastic shape factor, sf. In your particular case, sf = 1.822. Therefore, for your given problem, the bending stress is sigma = 8*P*L/(pi*d^3) = 8(22 241 N)(1829 mm)/[pi*(50.8 mm)^3] = 790.16 MPa. The ultimate bending stress level is therefore R = sigma/(sf*Sty) = (790.16 MPa)/[1.822(214 MPa)] = 202.7 % > 100 %. Ensure R does not exceed 100 %. Therefore, the above indicates you need to, e.g., increase the beam section modulus, and/or decrease the beam length.
 
  • #6


reign16 said:
what is the cause of that failure??

What failure?

CS
 

1. What is the purpose of failure analysis on a 2" OD solid 6063 aluminum round bar?

The purpose of failure analysis is to determine the root cause of the failure of the aluminum round bar. This can help identify any design or manufacturing flaws, material defects, or external factors that may have contributed to the failure.

2. What are the common failure modes of a 2" OD solid 6063 aluminum round bar?

The common failure modes of this type of aluminum round bar include fatigue failure, ductile or brittle fracture, and corrosion. Other potential failure modes may include plastic deformation, creep, or stress corrosion cracking.

3. What methods are used in failure analysis of a 2" OD solid 6063 aluminum round bar?

Typically, failure analysis involves a combination of visual inspection, mechanical testing, and chemical analysis. This may include techniques such as microscopy, spectroscopy, and non-destructive testing to identify any defects or failure mechanisms.

4. How can failure analysis results be used to prevent future failures?

The findings from failure analysis can be used to improve the design, manufacturing processes, and material selection for the aluminum round bar, as well as identify any external factors that may have contributed to the failure. This can help prevent similar failures from occurring in the future.

5. How long does a failure analysis of a 2" OD solid 6063 aluminum round bar typically take?

The duration of a failure analysis can vary depending on the complexity of the failure and the methods used. It may take anywhere from a few days to several weeks to complete a thorough analysis and provide a comprehensive report on the findings.

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