Local stress in ear-type supports
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A heat exchanger is designed with a stress of 1.28 MPa, a design temperature of 150 degrees, an inner diameter of 3000 mm, a wall thickness of 16 mm, a corrosion allowance of 1.5 mm, a length of 5200 mm, a weight of 46 tons, an air pressure of 300, and an acceleration of 0.24； I have chosen the standard ear-type supports A8, in quantity of 4. The allowable bending moment [ML] cannot be found in the tables; I would like to carry out calculations using local stress. In SW6 software, how should I enter the values for the radial force along the Z-axis, the horizontal force along the X-axis, the horizontal force along the Y-axis, the bending moment along the Z-axis, the bending moment about the X-axis, and the bending moment about the Y-axis? Please advise me Thank you!
According to Appendix A of JB/T4712.3-2007, the load Q acting on the support is calculated; this value represents the force Fx parallel to the axis of the housing. Then, Fx is multiplied by the lever arm (i.e., the distance from the center of the bolt hole in the bracket to the outer surface of the gasket), thereby yielding My. Once this value is obtained, it can be used in SW6 for further calculations. The above calculation is based on the rectangular attachments on the column shell; the length and width of these rectangular attachments correspond to the sides of the gusset plates. The additional thickness of the cylinder wall is: corrosion allowance + negative deviation of the cylinder material. Note: For the distance L \"between the attachment center and the tangent to the head\", if this value does not meet the requirements, a length greater than that suggested by the system can be entered; this has little impact on the calculation results.
I would like to ask the experts above: How are the positive and negative signs for Fx and My determined? Don’t I need to enter codes for the other Fy, Fz, My, Mz? Thank you!
Reply to 3# yzs1982: Fx and My should be positive, while all the other values such as Fy, Fz, My, and Mz should be entered as 0
Can’t it be determined using the linear interpolation method in Appendix B?
Fx and My are both positive, while all the other values of Fy, Fz, My, and Mz should be entered as 0. So Fx and Mx are both positive, right?
It seems to be My; I’m a bit confused.
It seems that using the support formula is simpler for calculations; the formula can be found in the chapter on standard ear-type supports