Calculation of strength and seismic stability of ball valves
By the order of OOO NPO "Armgazinvest", specialists of NTC APM company performed calculation of strength and seismic resistance, taking into account the requirements of GOST 30546.1 ball valves DN 100 PN 160 and DN 15 PN 160.
Three-dimensional solid models of cranes, created by the customer's specialists with the help of COMPASS-3D software, were presented as initial data.
The calculation model was prepared using the APM FEM - finite element strength analysis system for KOMPAS-3D. The calculation was carried out using the APMStructure3D module of the automated calculation and design system for mechanical equipment and structures of APM WinMachine, part of the CAD / CAE settlement complex.
The calculation models were formed as follows:
- The original models were loaded into KOMPAS 3D;
- A specialized library of strength analysis APM FEM was connected;
- Fixing was established, loads were applied from the working medium and from the pipeline side;
- In the automatic mode contact zones and finite element mesh were created;
- The resulting models were transferred to APMStructure3D;
- Elements of the assembly were assigned the required material;
- Thermal action from the working medium;
- The necessary type of calculation was carried out;
- The results obtained were evaluated.
At the first stage, the natural frequencies of the ball valves were calculated. In accordance with the value of the first natural frequency and the items 4.2 and 5.6 of GOST 30546.1-98, the values of vertical and horizontal accelerations are selected. For a comprehensive assessment of seismic resistance, two options for the combined effect of vertical acceleration and acceleration in the horizontal plane along and across the crane axes are considered.
To assess the strength, the simultaneous effect of excess pressure of the working medium of cranes, loads on the pipeline side, as well as changes in the temperature of the working medium from -60 ͦ C to 80 ͦ C, is considered.
To view the calculation results for each individual object, click on the corresponding icon.
Ball Valve DN 15
Model of the crane DN 100
Analyzing the presented results for all the calculated variants of model downloads, we can draw the following conclusions:
- Seismic impact does not make a significant contribution to the overall picture of the stress-strain state of the crane, since the stress level from the action of the seismic load both along the axis of the nozzles and perpendicular to the axis of the nozzles does not exceed 1 MPa.
- Comparing the maximum operating stresses with the allowable yield strength for a given steel, we can assume that the structural strength condition is satisfied.