Discussion Overview
The discussion centers around the concept of proof load for bolts, including how to calculate or determine it. Participants explore definitions, measurement methods, and specific values related to different types of bolts, with a focus on both theoretical and practical aspects.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- Ana inquires about the definition and calculation of proof load for bolts, indicating difficulty in finding information.
- CS states that proof load is the load tested above the normal working load to verify the design.
- Another participant claims that proof load is slightly below the yield strength and emphasizes that it should be measured through tensile testing.
- araanandv2 suggests an average formula for calculating proof strength as Sp = 0.90*Sty, where Sty is the bolt's tensile yield strength, but notes that published values for each bolt property class are more accurate.
- Another participant clarifies that the ease of finding proof strength values applies primarily to carbon steel bolts marked with specific property classes.
- One participant discusses the importance of using proof load instead of yield strength due to stress concentrations at edges and threads, which can lead to local yielding.
- A participant asks about the proof load for AN bolts and NAS1351 screws, indicating a need for specific information on these types of fasteners.
Areas of Agreement / Disagreement
Participants express differing views on how proof load is defined and measured, with no consensus on a single method or value. Some participants propose formulas while others emphasize the necessity of measurement through testing.
Contextual Notes
There are limitations regarding the assumptions made about the types of bolts discussed, as well as the dependence on specific definitions and classifications of bolts. The discussion does not resolve the mathematical steps involved in calculating proof load.