[Discussion Post 20] How to choose the question about the allowable stress of materials?
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This post was last edited by kareale88 on 2019-3-4 15:54 bg4.png [Discussion Post 20] How to choose the question about the allowable stress of materials? Calculation formula for material allowable stress in GB/T150.1~150.4-2011 () Multiple choice question A. Tensile strength/safety factor ； B. Yield strength/safety factor ； C.Strength limit/safety factor ； D. The source of the elastic limit/safety factor question is "Material Mechanics" and GB/T150.1~150.4-2011 "Pressure Vessels". Do you have any other different opinions on the following sentences?: 1. In static strength design, the allowable stress of brittle materials is equal to (strength limit) divided by the safety factor. 2. In static strength design, the allowable stress of plastic materials is equal to (yield limit) divided by the safety factor. 3. The safety factor considered in the design calculation of the allowable stress method is not the safety multiple of the material strength reserve.
A. Tensile strength/safety factor
Let's debate whether there is any explanation. :handshake
I paid to download it from Baidu, and also pasted in some other information for your reference.：
The multiple-choice question is not appropriate. The standard requires the minimum value of several strength/safety factors. How to choose one alone?
So the question I'm looking at is a bit contradictory. Let's see if anyone has any other explanations, or make assumptions from several aspects and demonstrate it under certain conditions.
The moderator's answer to this question matches the one in the attached picture.
Calculation formula for material allowable stress in GB/T150.1~150.4-2011 () Multiple choice question A. Tensile strength/safety factor； B. Yield strength/safety factor ； C.Strength limit/safety factor ； D. The question of elastic limit/safety factor seems to reflect the word limit, combined with strength or yield, so I should choose C.
Calculation formula for material allowable stress in GB/T150.1~150.4-2011 () Multiple choice question A. Tensile strength/safety factor； B. Yield strength/safety factor ； C.Strength limit/safety factor ； D. If you choose the elastic limit/safety factor question, you must choose C. The allowable stress of the material considered in GB150 is the ultimate stress divided by the corresponding safety factor, and the minimum value is taken. Various ultimate stresses include strength limit, yield limit, endurance limit and creep limit.
It seems that this kind of topic is still relatively rare. To grasp the word of extremes, one must also grasp one of several extremes.