GSA User Group 2018
Brick elements and Soil-structure interaction Peter Debney Application Specialist
Motivation for brick elements
GSA soil-structure interaction analysis uses Pdisp solver for soil settlement analysis Pdisp solver is not an FE solver (semi-theoretical and semi-empirical)
Analysis sometimes difficulty to convergence Pdisp flexibility matrix is dense and can be very large‌ ‌ leading to inefficiency in memory usage
Motivation for brick elements
Would the analysis be better using brick elements in GSA to model soil rather than GsRaft? • Make analysis faster? • Fewer convergence problems? • Be more realistic in soil and interface modelling?
Brick elements would also be useful generally in GSA
Brick elements Solid 3D Element 8-node brick elements
Infinite 8-node brick elements
Brick element results Text output
Diagram
Brick element results Surface contour
Filled contour
Contact elements Gap element • compression only spring with initial gap Friction element • Ff = µ x Fn Lock-up element • 1D spring element with initial gaps Connector element • to connect two rigid bodies
Damper elements • Zero and 1D damper elements • Axial • Torsional • General
• For use in explicit time history analysis • To model • Explicit structural dampers • Absorbing boundary conditions
Damper elements Definition of damper element properties