The latest 3D release brings cutting edge functionality to users. The Concrete model (formerly Shotcrete) has become part of our standard soil material library, instead of a UDSM. Users can now apply the UDCAM-S model, together with a cyclic accumulation tool in order to estimate degraded soil properties based on cyclic loading for 3D analyses. The Dynamics module is extended with moving loads, scaling and plotting options for accelerations in Input, an updated mesh option and there’s much more. Read the full details below.
Users can assign Movement to point and line loads to model moving loads i.e. trains, cars or lorries. A movement function must be defined with a linear, harmonic or table based signal, specifying an initial velocity, acceleration, or variation of the velocity through time. Output is extended to show the location of the load through time for any of the saved intermediate steps, active loads are available in the loads table.
The Output program has been extended with new curve plots for dynamic analyses. The Fourier amplitude spectrum curve plot involves a fast–Fourier transform transforming a plotted quantity from the time domain into the frequency domain. The Arias intensity curve plot is used to determine the significant duration of a motion. The extreme values are now also highlighted in curve plots, but can also be inspected through tables which can be accessed when viewing the curve plots.
Dynamics users can now also perform dynamic calculations with the “updated mesh” setting in order to account for large displacements, which may occur during dynamic events, especially when dealing with liquefaction.
When selecting table input for accelerations in the displacement multipliers window for Dynamic multipliers, users are now offered tools to scale the dynamic signal by means of an overall scaling factor, or a scaling type based on a maximum multiplier. A duplicate button allows the users to quickly make copies of each scaled signal. The user can also inspect the Fourier and Response spectra and Arias intensity of their original and scaled signals in the Input program.
With the new zoom and view commands users can now orient their model in Output to script results generation for automated plot export or even model fly-throughs. Jupyter and the option to run Jupyter notebooks have been added, for organized storage and running of scripts with inline responses in the notebooks.
A new type of SoilTest is available, the Cyclic triaxial test. It enables users to easily simulate triaxial laboratory tests with cyclic loading in order to determine the dynamic properties of the soil. Users can evaluate the shear modulus G and damping ratio and determine the liquefaction potential for sand in undrained conditions.
Users can now import point clouds through the GUI. The point cloud is converted to a NURBSsurface and through a grid density option users can change how the NURBssurface approximates the point cloud. In the Flow conditions mode, a point cloud can be imported as well in order to generate a water level through the new import water levels button. IFC files can now also be imported. PLAXIS 3D filters the file, ensuring only objects relevant for the analysis are imported.
In Output users can now directly create load-displacement curveplots from post-calculation nodes of soil or structural elements where loads are applied. For rigid body objects users can now add the rigid body reference point as a post-calc curve point and create curveplots as well. All the information can also be retrieved through the Output command line, and through scripting. This makes it more user friendly to create load-displacement curveplots to for example assess the ultimate load capacity or time versus force development.
For large projects, users will experience improved rotation and selection tool response in Input, especially when dealing with imported geometries. Mode and phase switching speeds have been improved. The automatic Enhanced Mesh Refinement procedure is improved, noticed by the capability of PLAXIS 3D 2018 to generate meshes for models of even higher complexity. For Output a significant performance increase was realized for generating curves in Output, and loading times and phase switching response have been improved.
Based on the UDCAM (UnDrained Cyclic Accumulation Model) originally developed by the Norwegian Geotechnical Institute, PLAXIS now offers the simplified UDCAM-S model combined with a cyclic accumulation and optimization tool. Through the tool, users can transform the full cyclic load history into an equivalent number of cycles. This allows for determining stress-strain curves that are representative of the behavior of the soil in DSS and triaxial conditions. Through these different modes, the tool provides assistance in generating UDCAM-S material properties, which properly reflect the degraded soil conditions based on the simulated cyclic load.
The tabulate command has been extended allowing users to compare for example the activation state, assigned material sets or load values and much more, across a number of phases or a group of objects. Users can also select objects via the GUI and issue tabulate on the selection. This extension allows users to query their model in a convenient way to check the consistency and trace (potential) errors in their input.
An apply strength reduction option is added to structural elements and soil volumes. This option allows the user to now include structural elements, or exclude certain soil clusters from the safety analysis. This is for example useful for speeding up calculations, excluding clusters where the user knows nothing will happen anyway, or to exclude certain clusters that generate unrealistic shallow failure mechanisms.
The former UDSM Shotcrete model is available as a native PLAXIS model for VIP subscribers and has been renamed to Concrete model. The model was developed in cooperation with Graz University of Technology, and allows users to take into account time dependent strength and stiffness of concrete, strain hardening/ softening in compression and tension as well as creep and shrinkage. Most of the input parameters for the concrete model can be derived from standard uniaxial tension and compression tests. While the model was mainly developed to model the behaviour of shotcrete, it has also proven useful in applications related to soil improvements, for example jet grout columns.
The new tunnel splitting tool allows users to split off parts of one main tunnel as separate tunnels, while maintaining the geometrical consistency of the original tunnel. Each split off tunnel can have its own slicing, properties and Sequencing defined. With the splitting tool the user is offered full control of the sequence definition and tunnel advancement procedure in Staged construction, as each tunnel can have an independent pace of progressing the excavation, previously not possible when modeled through a single tunnel with its single sequence definition.
Additional information and alternative input parameters are available for segments and subsections, making it easier for the user to model tunnel cross-sections. Checks on the geometry are performed, warning about potential errors, especially useful with imported tunnel cross-sections. All is available through scripting as well, making automated model creation easier and more precise. Contraction has been revised and can now be modeled with the Sequencing mode.
Users can now add Reinforcement to their tunnels. and select between the previously existing Rock bolt, and the new Umbrella arch as configuration types. Spacing input has been simplified and reinforcement is now automatically added symmetrically, with the top of the tunnel as symmetry axis, further easing input.
PLAXIS 3D VIP subscribers can contact Sales to get their free licence upgrade.