Examples of tasks performed by PMD
Company VAMET Ltd. has solved a number of industrial, engineering and academic tasks in the fields of power engineering, chemical technology, mining and nuclear industries during its existence. Examples of selected tasks solved are listed below with a brief commentary and characteristics.
Thermal calculations
Steam valve
The focus of this project was the identification of critical areas of the steam valve design. The valve was loaded by extreme temperature and pressure shocks. First, a stationary temperature field was determined, serving as an initial condition for calculating the transient temperature field in the time range 0-60 s. Thermal stresses were superimposed to stresses due to pressure and finaly evaluated according to NTD A.S.I.
Linear thermo-elastic-static calculations
Gas cooler
Stationary temperature field, both elastostatic and seismic response was calculated. The model, discretized by means of semi-Loof shell elements, includes the inner installation, tube sheet and pipe bundles.
Natural frequencies and modes
Vessel for uranium cartridge
The vessel is intended for the transportation and storage of spent nuclear fuel. The seismic resistance of the apparatus, natural frequencies and modes and effects of vibration on the surrounding area was studied.
Seismic calculations
Gas cooler
Seismic response, consisting of quasistatic and modal parts was assessed. Resulting stress state was determined by SRSS (Square Root of Sum of Squares) method according to NTD A.S.I.
Linear (bifurcation) buckling
Ionic Filter - holder
The calculation was made within the evaluation of the anchoring of the Ionic Filter. The model was loaded by weight of the Filter’s pressure vessel. The aim was to determine the safety of the structure loaded by compression. Linear buckling model was used.
Thermo-elastic-plastic calculations
Gas cooler - socket
More accurate information on stress and local plastic deformation of the inlet steam socket was required. Therefore elastic-plastic analysis using small deformation theory and material non-linearity was performed. An ideally plastic material model was considered.
Geometrically non-linear calculations
U-pipe of an exchanger
Information on the extent of plastic deformation of the bent pipe was required. Data obtained was used to predict the lifespan of the equipment. Both material and geometric nonlinearity were considered. Elastoplastic model with isotropic hardening and total Lagrangian formulation was used.
Linear dynamic calculations - implicit integration and modal superposition
Dynamic response of the Ion filter
The PMD system provides solutions to the structural dynamic response of structures by using two standard approaches - direct integration (Newmark Method) and modal superposition. In this particular problem a forced vibration pattern of the structure was analyzed in a transient state. Newmark method was used.
Nonlinear dynamic calculations - explicit integration
Impact of cylidrical bodies
Response of a dynamic structure could be solved within PMD by two standardized approaches - direct integration (implicit, explicit methods) and modal superposition. The task was solved in cooperation with the Institute of Thermomechanics of Academy of Sciences of the Czech Republic. Stress wave propagation has been analysed and experimentally verified. The explicit scheme was used for numerical integration.
Calculations of contact
Pipe system component
Stress analysis was performed of a reinforced inlet socket of a steam pipeline, in the area of contact between the reinforcement and piping itself. Obtained contact stress formed input for calculation of creep damage.
