MasterFrame Concepts

Introduction

The following chapter outlines the basic concepts involved in using MasterFrame to model a physical structure, including modelling the loading applied to the structure and the support conditions. It can often be helpful to understand the general concepts behind a MasterFrame model when creating an analytic model of a real structure as this can assist in creating an appropriate structural model for the analysis. This can be particularly helpful when dealing with models involving Finite Element Surfaces.

MasterFrame models

MasterFrame uses an analytical model based on analytical nodes and analytical elements to model the interconnected 3-dimensional elements that comprise a physical structure. The analytical model used in MasterFrame forms a mathematical representation of the physical structure, from which the stiffness matrix, required as part of the analysis of the structure, is compiled.

Analytic Nodes – analytic nodes represent points in space. Nodes are associated with an ordered triplet which represent the global Cartesian coordinates of the point within the model space.

Analytic Member – analytic members are 1-dimensional line elements which are defined between two points in space, the points being represented by analytical nodes. Analytic members must be straight line segments.

Analytic nodes and analytical members together form a mathematical model of the whole, or part of, a physical structural element. These analytical elements represent the shear centre of the real element. In doubly symmetric structural sections, the shear centre and centroid are coincident and so for these type of structural section, the analytical member represents the element centroid.

Analytic members are always associated with two analytic nodes. The analytic nodes represent the end points of the analytic member. Several analytic members may be coincident at an analytic node, in which case the node represents the end point of several analytic members. Only one node may occur a point in space.

The physical properties of the physical sections are applied to an analytical member as a set of mathematical values. These mathematical values are used in the analysis and subsequent design modules. Regardless of the physical values assigned, the analytical members always remain 1-dimensional line elements.

Analytical nodes and analytical members can be used to form a MasterSeries physical member, which is itself a representation of a physical structural element. A MasterSeries physical member can comprise of one or more analytical members. An example of a physical member in a model would be a primary floor beam supporting secondary beams. The physical beam would be made up a several segments or beam portions, each segment being a single analytic member. The intermediate nodes would be shared among at least two analytic members, allowing for the connecting secondary members.

The MasterFrame physical members are given graphical properties which reflect the physical properties of the structural element they represent. MasterFrame physical members can be displayed in the 3D graphics and will have a section shape, orientation and dimensions which are representative of the real physical member. However, the 3-dimensional nature of the graphical view is purely graphical, since the underlying model is based on the analytical elements.

MasterFrame physical members can be connected and arranged within the model space to create a 2 or 3-dimensional model. The positions of the MasterFrame physical members represent the physical position of the elements of the structure to be modelled. The MasterFrame coordinates of the nodes representing the connections between elements represent the joints in the structure.

Once a model has been built, it can be viewed in both a wire frame and a 3D view. However, it is important to remember that the underlying analysis model is based on the wire frame model, which in turn is based on the member shear centres.

The intended functionality of MasterFrame is to minimise the time spent by the user dealing with analytical nodes and analytical members. In general, when creating or modifying a model within MasterFrame, the software automates the process of creating the MasterFrame physical members, with the creation of the analytical elements of the model being done automatically in the background.

Once a model has been partially or fully created, changes are often required to be made. These changes can include the layout of parts of the floor plans, adding or removing beams, or column positions or bracing members having to be added or repositioned. Wholesale alterations may need to be included or new parts of the structure added. The loadings on floors and roofs may also have to be modified. To make the user’s experience of modelling as simple as possible, MasterSeries provides a range of very useful tools for the quick altering and modifying of the members, etc. within the model.