Explosion response analysis
Gexcon's in-house Time-Domain Single Degree of Freedom (TDSDOF) software enables data to be presented as quasi-static design loads. These loads are presented in graphical form: quasi-static design load vs. structural natural period and ductile deformation capacity. The results can be applied both to structural and equipment design, e.g. input to design accident load specifications and equipment enquiry data sheets.
Structural resistance is assessed to SCI Technical Note 4 "Explosion resistant design" and TN5 "Stainless steel blast walls" (based on Eurocode 3 part 1). Reserves due to ductile capacity and membrane action are considered in the code-checking programmes used (spreadsheet based). The assessment technique together with detailed drawing review allows rapid screening to identify critical areas and more detailed assessment of weak areas. In some instances NLFEA will be recommended. NLFEA work is primarily by LSDYNA3D and handled by subcontract. For reassessments it is normally more cost-effective for NLFEA work to be undertaken only after the overall mitigation strategy has been formulated: our analytical methods are geared to this philosophy.
The in-house TDSDOF software can read FLACS output directly (scenario-based design) and has a pre-processor that can combine and average impulses. Time histories of deflection, resistance mobilised, acceleration, support reaction etc are given together with projectile energies for items which fail during the impulse load. This facility is useful for assessing cascade failures (multiple lines of defence) and is a necessary partner to FLACS assessment of platforms not originally designed for blast.
Where loads are determined by probabilistic methods the FLACS output is given both in terms of peak pressure and impulse duration. Structures are assessed to determine the probability of failure and the probable failure mode. Checks are then carried out for scenarios giving loads close to the assessed strength threshold so as to account for particularities of impulse shape.
Our response analysis tools can be used in conjunction with FLACS for onshore facilities (far-field effects) and anti-terrorist design of buildings.
Contact
Ronan Abiven
Phone no: +47 415 04 229
Email: ronan(at)gexcon.com
