Phase2 8.0Faster, easier,more powerfulthan ever.

Phase2 8.0

It’s faster, easier and more powerful than ever.

Phase2 8.0 is an important upgrade which will benefit advanced users and beginners alike. This

article summarizes the major new features of version 8.0 including:

1. 64 bit multi-core parallel processing

2. Probabilistic analysis using the point estimate method

3. Discrete strength function

4. Customized mesh regions

5. Many other additions and improvements

64-bit, Multi-core Parallel Processing

Phase2 8.0 is the first Rocscience program available as a 64-bit version, and is built for Intel 64

microprocessor architectures. Intel 64 is the most popular 64-bit microprocessor architecture

among Windows users that run 64-bit versions of the Windows operating system. For Phase2

users, this new 64-bit version means that they can run much larger models with many more

degrees of freedom than ever possible with the 32-bit version of the program.

Figure 1 – Kersten lecture model, reinforced tunnel beneath excavated slope

With larger models, the computation time needed to solve the problem increases multifold.

Phase2 8.0 is designed to use all processor cores available in the system to accelerate

computation and speed up analysis. Using state-of-the-art multi-threading techniques, Phase2

8.0 users can expect a 2, 3, or 4+ fold faster computation time commensurate with the number

of cores on the system. With multi-core processors being common place today, Phase2 8.0

optimizes its use of the system’s resources to quickly provide users with solutions.

Underneath the hood, Phase2 8.0 has undergone significant improvements to boost its overall

scalability and performance. In terms of complex models with joint networks and advanced

mesh generation, Phase2 8.0 is now even more efficient so users can rapidly create detailed

models and denser meshes in much less time, using much less memory. This, combined with

64-bit processors and parallel processing, enables Phase2 8.0 users to create, mesh, compute

and analyze much larger models much faster than previously possible while having the same

ease-of-use that Phase2 is known for.

An example of the improved performance of Phase2 8.0 64-bit is summarized in Table 1 using

Example 1: Kersten Lecture (without liners).

Number of DOFs Meshing Time (s) Compute Time (s)

V7 V8 V7 V8 V7 V8

51190 56464 50 5 347 65

174986 176918 546 15 1994 334

n/a 1254369 n/a 95 n/a 5617

Table 1: Comparison of meshing and compute times of Phase2 7.0 32-bit versus Phase2 8.0 64-

bit using Example 1. Machine specs: Intel® Xeon® CPU E5520, 2 processors, 4 cores each, 24 GB

RAM.

For more information about 64-bit versus 32 bit computing, click here to read another article

published in an earlier Rocscience newsletter, during the preliminary development period of

Phase2 8.0.

Probabilistic Analysis

Probabilistic finite element analysis has become a practical possibility in recent years due to the

tremendous advances in processor speed and data storage capability. As a first step in this

direction, Phase2 8.0 offers probabilistic analysis using the point estimate method.

For the point estimate method, random variable distributions are represented by two point

estimates at plus / minus one standard deviation from the mean. For n random variables the

analysis is repeated for all possible combinations of point estimates, which gives 2^n solutions.

Assuming normal distributions for all input random variables, the mean and standard deviation

of the analysis results can be determined.

The point estimate method has proven to be a very useful method of obtaining statistical

analysis results with very simple input data. At present, random variables may include material

properties, joint properties and field stress (additional variables may be considered in future).

Figure 2 illustrates the definition of random variables for a material with Hoek-Brown strength

parameters. Note that only the mean and standard deviation are required for each variable.

Figure 2 – input dialog for material property statistics

In the Phase2 Interpret program, you can view the mean and standard deviation of analysis

results (e.g. displacements, stresses) in the form of contour plots on the model. You can also

view error plots of data along any material query (e.g. the minimum and maximum

displacement values along a boundary), and you can view statistical shading of yield zones.

These are illustrated in Figure 3 on the following page.

Figure 3 – statistical analysis results displayed in Phase2 Interpret

Probabilistic analysis can be used in conjunction with SSR slope stability to determine a

probability of failure for a slope model. Preliminary testing indicates that results are consistent

with limit equilibrium probabilistic analysis results produced by the Rocscience slope stability

program Slide.

For further information, the following tutorials will be very helpful. In the first example, a tunnel is analyzed with three random variables and analysis results are discussed.

Phase2 Tutorial # 31 – Probabilistic Analysis

The second example demonstrates how to carry out a probabilistic slope stability analysis using

SSR analysis and the point estimate method. Results are compared with Slide.

Phase2 Tutorial # 32 – Probabilistic Slope Stability Analysis

Discrete Strength Function

The Discrete Strength Function option in Phase2 8.0 allows you to define Mohr-Coulomb shear

strength parameters (cohesion, friction angle) at a grid of discrete points within a material. The

shear strength for each finite element is interpolated from the data at the grid points. This

allows you to define any type of strength distribution within a material (e.g. linear, non-linear,

random).

Elastic modulus can also be defined at each grid point, and randomization can be applied to the

values of strength or modulus by defining a statistical distribution for each parameter.

Figure 4 – discrete strength function input dialog

Figure 5 – randomize option for discrete strength function parameters

For example, the following model shows a random distribution of soil cohesion for a bearing

capacity problem, generated by the discrete strength function option. Random strength

distributions can be used to simulate materials with heterogeneous properties.

Figure 6 – random distribution of cohesion generated by discrete strength function

Customized mesh regions

Ease of mesh generation and the ability to customize the mesh has always been a hallmark of

Phase2.

In Phase2 8.0, an important new capability has been added to the mesh customization options:

it is now possible to define regions of uniform mesh density within a graded mesh.

This allows you to create a dense uniform mesh in critical areas of the model (e.g. around

excavations), while maintaining a graded mesh outside of these regions. This combines the

advantages of uniform and graded meshing - you can easily maximize the mesh density where it

is needed, while keeping the overall number of elements low.

Figure 7 – Mesh setup dialog and application of customized mesh region

Custom mesh regions can be selected with a single mouse click (any closed region of the model)

or you can click and drag a rectangle over any area of the model. In either case, Phase2 will

create a uniform mesh with a user-defined average element length in the selected region.

This new feature has been successfully used in preliminary studies of brittle spalling around

excavations, where fine meshes are required in order to capture the material behaviour.

For further information, please see the following Developer’s Tip. Advanced Mesh Regions

Additional new features and improvements

Additional new features you will find in Phase2 8.0 include:

Greatly improved speed of file saving and loading for large models

Improved mesh quality for models with large joint networks due to application of

geometry cleanup

Much faster meshing, file saving and loading for models with large joint networks

Ability to define residual (post-peak) properties for: Young’s modulus, tensile strength

and joint strength

Display of property tables for bolts, liners, joints, composite liners

For a complete listing of What’s New in Phase2 8.0 click here.

Summary

With new 64-bit and multi-core parallel processing, Phase2 8.0 is capable of solving much larger

and more complex models in less time than ever before. The version 8 upgrade is highly

recommended for advanced Phase2 users who require state-of-the-art modeling features and

maximum computational power. The many new features and improvements in version 8 will be

appreciated by both new and experienced users alike. For a free evaluation copy contact us at

software@rocscience.com.