p6g2p6
Mechanical
- Jul 28, 2021
- 35
Hi,
I am still new to using the AMSE BPVC, and I am a little confused by the bolt load calculations. I understand that you need to calculate the bolt loads required for the design conditions (Wm1 and Wm2) and select the greater of the two to use as your minimum required torque, however I don't fully understand the need for the flange design bolt load parameter, W. Is this only used for calculating the flange bending moments, based off the assumption that the actual bolt load will be higher than the calculated minimum bolt load? Why wouldn't you just use what your targeted torque is going to be to calculate the bending moment on the flange?
For example, I am going through these calculations right now to determine the minimum required bolt load. I calculated a value of approx. 100,000 lbs for the required bolt load for effective gasket seating (Wm2), which would result in a bolt stress well within the yield stress of the bolt. I was told to aim to torque the bolts to an extent that will result in the bolt stress being in the 40-60% range of its yield stress. Therefore, I figured my next step would be to calculate the flange stress and the gasket stress using the 40% bolt stress (which would result in a bolt load of approx. 1,000,000 lbs) and ensure that its within the limits of the flange and gasket material. This way I know that I will have enough clamping force to provide an effective seal, while also staying within the mechanical limits of the bolts, gasket, and flanges. Is this an acceptable method?
Thanks in advance.
I am still new to using the AMSE BPVC, and I am a little confused by the bolt load calculations. I understand that you need to calculate the bolt loads required for the design conditions (Wm1 and Wm2) and select the greater of the two to use as your minimum required torque, however I don't fully understand the need for the flange design bolt load parameter, W. Is this only used for calculating the flange bending moments, based off the assumption that the actual bolt load will be higher than the calculated minimum bolt load? Why wouldn't you just use what your targeted torque is going to be to calculate the bending moment on the flange?
For example, I am going through these calculations right now to determine the minimum required bolt load. I calculated a value of approx. 100,000 lbs for the required bolt load for effective gasket seating (Wm2), which would result in a bolt stress well within the yield stress of the bolt. I was told to aim to torque the bolts to an extent that will result in the bolt stress being in the 40-60% range of its yield stress. Therefore, I figured my next step would be to calculate the flange stress and the gasket stress using the 40% bolt stress (which would result in a bolt load of approx. 1,000,000 lbs) and ensure that its within the limits of the flange and gasket material. This way I know that I will have enough clamping force to provide an effective seal, while also staying within the mechanical limits of the bolts, gasket, and flanges. Is this an acceptable method?
Thanks in advance.
