Modules Currently Available

MAESTRO Basic Package

The MAESTRO Basic Package includes the graphical modeler for developing MAESTRO structural models and full post-processing capability. This includes full model viewing capability and generation of loads for input to the MAESTRO Analysis/Evaluation Solver. Post-processing includes such features as graphical display of loads, deflections, stresses, and failure evaluation results from the MAESTRO Analysis/Solver. MAESTRO’s two central operations, analysis and evaluation, are also performed by this module.

This module completes a finite element analysis and structural integrity evaluation (failure modes and other limit states based on Professor Owen Hughes’ textbook Ship Structural Design, Wiley, 1983) of every member and every load case. The solver performs three integrated tasks:

• Finite element analysis to obtain the actual stresses and deflections throughout the model for all load cases.
• Calculation of the failure stresses for all relevant modes of failure, for every member and every load case.
• A complete evaluation of the structural adequacy of every member under each load case, and thereby obtaining a rigorous assessment of the current design of the structure, which includes identifying the most critical failure mode and load case for each member.

Fine Mesh Analysis with Alternate Limit State Criteria

The MAESTRO Fine Mesh module allows the user to automatically create refined 3-D FEA models of any portion of the MAESTRO global model while maintaining the original scantling properties and loads. The user creates a group made up of elements from the “area of interest” then refines the group based on two options. The first option being the Top-down mode.

In this mode, Fine Mesh Analysis applies displacements from the global analysis to the fine mesh model for boundary conditions. In the Embedded mode (the second option), Fine Mesh Analysis replaces the coarse mesh portion of the model with the fine mesh. The Finemesh module also includes several alternative limit state criteria for use in MAESTRO’s adequacy parameter evaluations: ABS-HSNC (High Speed Naval Craft), ABS-Offshore Buckling Guide, ABS-SVR-2002, CSR-OT, and Bureau Veritas-Naval Vessel Rules.

Natural Frequency Analysis including Added Mass

MAESTRO allows the user to perform a natural frequency analysis and visually identify the dominant global modes. The analysis can be performed in a dry or wet mode, in which the added mass of the seawater is automatically applied to the “wettable” elements based on the immersion condition.

NASTRAN Translator

This module translates either the entire MAESTRO finite element model or a portion thereof into Nastran, including loads and groups (from FEMAP Neutral files). Alternatively, Nastran models can be translated into MAESTRO (only Nastran geometry).

MAESTRO Hydrodynamic Loading & Analysis

The MAESTRO-Wave module provides the ship designer with an integrated frequency-domain/time-domain computational tool to predict the motions and wave loads of floating structures. Because this tool is integrated into the MAESTRO interface, the learning curve is greatly reduced and the need to transfer data between programs is eliminated. MAESTRO-Wave takes advantage of the existing structural mesh and defined loads to formulate the equations of motion. This approach results in a perfect equilibrium for the structural model so no inertia relief or artificial loads are required to balance the model. Bending moments, shear forces and torsional moments are all automatically in closure. MAESTRO-Wave can also account for tank sloshing loads and provides several roll damping options. The computation of hydrodynamic forces is based on one of several user-selected analysis methods:

• 3D panel potential theory using the zero speed Green function with a speed correction parameter
• 2D Strip Theory using either the Free Surface Green Function or the Rankine Source Method
• 2.5D High Speed Strip Theory using the Rankine Source Method including the forward speed term

Regardless of the method used, the MAESTRO-Wave output provides a unit wave database and panel pressure loads for all of the speeds, headings, and wave frequencies run. A variety of visualizations and output data are available to aid the user with post-processing.

Extreme Load Analysis

The ELA module imports unit wave load data from a hydrodynamic analysis (MAESTRO-Wave or other) via *.smn file format. It then allows the user to calculate hull girder load response RAOs, and provides the necessary short-term and long-term statistical computations to predict extreme values of the maximum loads for a given vessel. This includes the ability to define or import wave scatter diagrams, operational profiles, and wave spectra, as well as to compute hull girder RAOs for the most common dominant load parameters (e.g., vertical bending moment). Finally, extreme equivalent regular waves (equivalent design waves) are internally computed and selected for assessment of extreme global loads. The user has a variety of options to add still water loads to the wave-induced loads and to re-balance these components.

Spectral Fatigue Analysis

The Spectral Fatigue Analysis (SFA) module provides the ability to perform global fatigue screening of the vessel. The SFA module introduces additional functionality to the ELA module to compute Stress RAOs, displacement RAOs, define and associate structural groups to SN curves and Stress Concentration Factors (SCFs), and compute fatigue damage based on the Miner cumulative damage principle.

MAESTRO Structural Optimization

The MAESTRO Optimization module (not for resale) allows optimization of a given structure ranging from a single stiffened panel to a hull girder cross section to a full-ship model using a multi-objective, heuristic-based optimization approach. The optimization uses the MAESTRO loading patterns and ultimate limit state (ULS) evaluations (and their safety factors) to optimize the structure for minimized weight and cost while maximizing structural safety, given a set of user-defined constraints. These constraints can be defined by structural member size limits, ratios, or by the MAESTRO structural element library.

During the optimization setup, design clusters are defined which ensure scantling properties are consistent throughout the cluster to support realistic and producible designs. For each optimization iteration, a new finite element analysis is run with the updated scantling properties and adequacy parameters are evaluated and used to optimize the structure for the next iteration. The optimization module allows the user to select from a variety of optimization methods including Simulated Annealing, Genetic Algorithms, Monte Carlo, and an exhaustive search.

Modules Not Currently Available

ALPS/HULL

The ALPS/HULL module calculates the progressive collapse behavior of ship hulls.

ALPS/ULSAP MAESTRO Module

The ALPS/ULSAP module adds an additional set of limit state criteria to MAESTRO’s automatic failure mode evaluation.

ProColl Hull MAESTRO Module

ProColl Hull provides the ability to calculate compartment level progressive collapse behavior of lightweight aluminum ship structures and conventional steel vessels.

Slamming Analysis

Slamming analysis in Hydrodynamic Loading & Analysis package.

U.S. Navy DPC100-4/MIL-519 Criteria

The MAESTRO DPC100-4/MIL-519 module applies the traditional U.S. Navy design procedure and structural strength criteria.

Underwater Shock Analysis (UNDEX)

Underwater Shock Analysis (UNDEX) in Hydrodynamic Loading & Analysis.