Solver

  • New version of LIRA-SAPR program presents high-precision (with nodes on sides) linear finite elements (plates and solids). With these elements the program significantly improves the solution accuracy even with coarse mesh.
  • The sixth degree of freedom (DOF) for the shell is realized rotation about the axis perpendicular to the plane of the plate. With new DOF the program improves the quality of the FE model when solving certain problems (to simulate mass eccentricity, to avoid geometrically unstable models, etc.) without mandatory use of special simulation techniques. Appropriate setting is added to analysis parameters.
  • To solve dynamic problems with the spectrum method, an algorithm of mass condensation is implemented; it can significantly reduce the time to search for mode shapes. In this approach when mode shapes are searched for, only masses of the main structure are considered, while masses from the flexible part (for this problem the user is not interested in natural vibrations of this part) are concentrated at the common nodes. Eccentricities for account of torsion may be assigned to the nodes where mass condensation is performed.
Mass condensation for dynamic analysis
Mass condensation for dynamic analysis
Advanced settings to manage the analysis procedure
Advanced settings to manage the analysis procedure
  • An alternative method of summing up components during earthquake analysis is implemented. This algorithm enables you to consider the proximity of frequencies and recommendations of many regulatory documents in analysis & design of earthquake-resistant construction, for example, formula (5.9) mentioned in paragraph 5.11 of SP 14.13330.2018.
  • New dynamics module is introduced according to the spectra NTP RK 08-01.1-2017 'Design of earthquake-resistant buildings and structures', referred to by NP to the SP RK EN 1998-1: 2004/2012 (R2).
  • New option to carry out 'Time History Analysis' after using the ASSEMBLAGE system or 'Step-type nonlinearity'. That is, it is possible to take into account the stress-strain states of structures before dynamic load due to the generation the history of loading / erection.
Verification test to evaluate the solution accuracy when high-precision FEs are used
Verification test to evaluate the solution accuracy when high-precision FEs are used
Verification test to evaluate the solution accuracy when standard FEs are used
Verification test to evaluate the solution accuracy when standard FEs are used
  • New variant of the iterative behaviour of the FE of joint is introduced. With this variant it is possible to avoid the disadvantages of the step-type analysis method. The iterative method has the following advantages: the element is turned off in uplifting, the element is turned on when direction of load is changed, the force in iterative element will not be greater than allowed one. See demonstration "Analysis of large panel buildings in LIRA-SAPR' (slide 21)
  • For iterative and step-type FEs of the platform joint, shear stiffness may be corrected depending on the vertical deformation.
  • For problems with 'Time history analysis', load cases with dynamic loads, masses and damping forces may have arbitrary numbers.
  • It is possible to define the local failure to elements in problems with 'Time history analysis' (option is available with the new system 'Progressive collapse').
Comparison of analysis results for high-precision and standard FE
Comparison of analysis results for high-precision and standard FE
Pathological test from verification report of LIRA-SAPR (volume II)
Pathological test from verification report of LIRA-SAPR (volume II)
  • Enhanced options for solving problems by the iterative method. In the analysis you can use:
    • 'Method 1' classic method of compensating loads;
    • 'Method 2' modified method of compensating loads, it is recommended to use this method for problems with structural nonlinearity;
    • 'Auto select' convergence rate is evaluated during analysis and appropriate method for solution is selected.
  • New types of FE: 245, 246 and 247 (physically nonlinear analogues for FE of thick shell).