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OFFICIAL LANGUAGE OF geselem.hu, ANY FILES, APPLICATIONS DOWNLOADED FROM geselem.hu IS HUNGARIAN.
ENGLISH VERSION OF geselem.hu, AND ENGLISH VERSION OF ANY FILES, APPLICATIONS DOWNLOADED FROM geselem.hu IS ONLY FOR REFERENCE.
Help for geselem.exe
General description
Model building
Structure
Constraints
Loads
Further information
Calculation
Results
Time limitation
Main window
Handling the mouse
Menu
File menu
View menu
Settings menu
Modify menü
Finite elements menu
Home
General description
OPERATIONS BEFORE CALCULATION. (MODEL BUILDING.)
==== Building the structure. ====
The structure to be modelled has to be built up from a finite number of elements. These elements can be straight beams or triangular shaped plates. During static calculations the elements are represented by their nodes. Every element has its own spatial right-handed Cartesian coordiante system, called the local system. In this system, the local degrees of freedom of the element are defined, these can be nodal displacements and rotations. During the calculation the nodal deformations (displacements and rotations, respectively) arising on the structure under the given constraints and loads are calculated. From this result, after further calculations the reaction forces acting in supports and the force and moment diagrams of beam elements are yielded. The element "set" of the application is - currently - comprising of threeo kinds of elements; their features are summarized in the chart below.
----------------------------------------------------------------------------------------------
! ! ! Degrees of freedom of nodes !
! Element ! Number of nodes !-----------------------------------------!
! ! ! Displacement ! Rotation !
! ! ! ! !
!--------------------------------------------------------------------------------------------!
! Truss ! 2 ! 1 ! - !
! ! (in the end points) ! (in X direction) ! !
!--------------------------------------------------------------------------------------------!
! ! 2 ! 3 ! 3 !
! Beam ! (in the end points) ! (in X, Y and Z ! (around X, Y and Z !
! ! ! directions) ! axes) !
---------------------------------------------------------------------------------------------!
! Constant strain triangle ! 3 ! 3 ! !
! (CST) ! (corner points) ! (in X, Y és Z ! - !
! ! ! directions) ! !
!--------------------------------------------------------------------------------------------!
! Triangular bending element ! 3 ! 3 ! 2 !
! (united with CST) ! (corner points) ! (in X, Y és Z ! (around X and Y !
! ! ! directions) ! axes) !
----------------------------------------------------------------------------------------------
The local coordinate system and the nodal degrees of freedom of the elements are shown by the figures below.
The local X axis of truss element coincides with the neutral axis of the beam, the origin is on one end of the beam which is a node as well. There are one degree of freedom per node, which is translation aligned with the neutral axis, i.e. this element is able to simulate a rod under tension or compression. Therefore the directions of the other two axes of the local system are irrelevant.
The local X axis of beam element coincides with the neutral axis of the beam, the origin is on one end of the beam which is a node as well. The other two axes of the local coordinate system must be located such that they coincide the principal axes of the cross section which contains the origin.
The oroigin of the local coordinate system of constant strain triangle (CST) element coincides the first corner point of the triangular shaped element. (The corner which is given as "Point 1" during creation of the element.) The local y axis is aligned with the section connecting the first and second corner points, the positive direction of the Y axis points towards 'Point 2". The local X axis lies in the plane of the triangle so that the X coordinate of the third corner point is positive.
The triangular bending element contains a CST united with a 9 dof nonconforming triangular bending element, with the field variable expressed in natural coordinates for the latter.
The means of building up a structure comprising of elements, is placing the elements in a spatial right-handed Cartesian coordinate system, called the workpiece coordinate system. Naturally, the local system of the elements and the workpiece coordinate system does not coincide in general, therefore a degree of freedom which is unidirectional in the local system became three directional in the global system. The elements can connect to each other at their nodes, to establish a connection, one has to place the nodes to the same point in space (in workpiece coordinate system); the connection of the elements means the automatic connection (communizing) of the respective degrees of freedoms as well. I.e., if placing two truss elements in workpiece system such that one of their nodes get to the same place of space, then their displacement degrees of freedom in that node become common, consequently can have only a common value. As truss elements does not have rotation degree of feedom, connecting their degrees of freedom simulates a (friction free) ball-and-socket joint (spherical joint) linking. Connecting nodes of beam elements means, that, in the common node, the elements can neither translate nor rotate relative to each other, this simulates continuous material connection. Connecting nodes of truss and beam elements simulates ball-and-socket joint, implicitly.
When building in an element one has to input its strength properties as well:
Truss element: area of cross section (A), modulus of elasticity (E). The material is isotropic.
Beam element: area of cross section (A), modulus of elasticity (E) and shear modulus of elasticity (G) (the material is isotropic), area moments of inertia with respect to principal axes (Iyy, Izz), polar moment of inertia (Ipo). (If the element is loaded by twisting moment then the cross section must be circular.)
Constant strain triangle element: width, modulus of elasticity (E, isotropic material), Poisson's ratio.
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==== CONSTRAINTS ====
At the nodes of the structure constraints can (and have to) be defined. Constraint means known deformation, by means of constraints is the structure (and all of it's sub-structures) supported, i.e. bound to its environment. Constraints have to be applied such that the internal constraints existing inherently between the connencted parts of the structure (these are automatically created during model building) and the applied external constraints (shortly: constraints) together have to assure, that the whole structure and any part of the structure as well, has to be completely constrained. The structure can also be over constrained, but, off course, must not be partially or improperly constrained.
IMPORTANT NOTICE ! (Also) proper application of constraints is the responsibility of the user. The program does not warns if constraining of the structure, or a part of the structure is not proper ! In such case, the "results" provided after calculation are useless. In many case it is not easy to recognize that the result is wrong, therefore care is needed when defining constraints.
At the end of calculation a trial vector is generated. If one or more elements of it significantly differs from 1 (unity), then a possible reason is improper constraining. (See the description of calculation as well.)
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==== LOADS ====
External loads can be operated on the model. Loads can be concentrated forces or moments acting on the nodes. The necessary condition of defining concetrated force on a given node is that displacement must exist amongst the degrees of freedom of that node - i.e. concentrated force may act on any node. The necessary condition of defining concetrated moment on a given node is that rotation must exist amongst the degrees of freedom of that node.
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==== FURTHER INFORMATION ON MODEL BUILDING ====
The model is three dimensional in every case. Two dimensional cases can also be simulated of course, but one has to pay attention to that the program handles the structure as three dimensional.
Units: There is no possibility to assign units to input data, and no units are assigned to the results. It is the users task to be consequent during entering the inputs and interpreting the results. Example: If length is given in mm (= millimeter, as unit is thought after the entered number), area is given in mm2, area moment of inertia is given in mm4, modulus of elasticity is given in N/mm2, force is given in N, moment is given in Nmm, then displacement is yielded in mm, force in N, moment in Nmm.
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CALCULATION
Every part of the structure stays under the elasticity limit.
Main steps of calculation:
Creating the global stiffness matrix. (K)
Creating the global load vector. (P)
Incorporating boundary conditions (constraints).
Calculating the global nodal deformations (Fi) by solving the equatuion system K.Fi = (P)
Calculating the vector of reaction forces and moments. (R)
Calculating the forces and moments acting on beam elements (force and moment diagrams): tension-compression (N), shear force (Qy, Qz, Q), torsion moment (T), bending moment (My, Mz, M).
In order to check the reliability of computation the K.FiPRÓBA = PPRÓBA equation system is also solved, where the ith element of vector PPRÓBA equals the sum of the elements comprising the ith row of matrix K, i = 1..number of degrees of freedom (DOF). I.e., the accurate (theoretical) result of this equation system is a vector in which all element equals 1. The real reult is FiPRÓBA, the element of which can be viewed in the "Trial" column of the Equation system viewer. The closer these elements are to 1, the more accurate the solution of the trial equation system and the equation system belongig to the actual computation task is. By clicking on the "Error" radio button, the relative error of the elements of the trial solution can be displayed using the formula (FiPRÓBAi-1)/1*100%.
Number representation during calculations, except solving the equation system:
Range: +/- 5.0x10-324 .. 1.7x10308.
Significant digits: 15.
Number representation during equation system solving:
Range: +/- 1x10-32768 - 1 digit .. 1x1032767 - 1 digit.
Significant digits: customizable by the user, lower limit is 16, upper limit is the memory available.
If the value of any result or interim result flows over the given range, a calculation error occurs.
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RESULTS
Results, which can be visualized after calculation:
Reaction forces and moments.
Force and moment diagrams of beam elements (N, Q, T, M). (These can only be visualized on the original structure, and cannot on the deformed one.)
The deformed figure of the model. (Can only be represented without the force and moment diagrams.) The value of the function simulating the deformation of the neatral axis of the beam is calculated in 10 points along the beam and the results are connected by straight sections.
After calculation the description of the model and the main results are written into a .txt file.
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TIME LIMITATION
The application contains one limitation: the model created can be edited only for a given period of time starting from the beggining of building the model. Actually, this period of time is 30 days. (Please note: the 30 days limitation is not related to the application but to the model build up using the application.) The period during which the model file is editable starts with starting the application or choosing File->New from menu, respectively. After the given period of time elapsed the model is no more editable, however the calculation results are available, assuming that the calculation succesfully finished before the time period elapsed, or at least the calculation can be succesfully executed at the moment when the period elapse.
At the moment when the period elapse, an attempt is automatically made to do the calculation. After this calculation .txt file is not created regardless of how this function is configured.
If the model (structure of the model) is not edited after the last succesful calculation which was made within the allowed time period, then the result of this calculation exactly match the result of the automatic calculation at the end of the time period, of course.
If such a model is opened, for which the allowed time period for editing was elapsed beforehand, then the calculation is automatically made after opening.
=== Main window ===
=== Handling the mouse ===
Beside the functions common in Windows, the following operations can be pursued on the graphic area (in which the figure of the model appears) of the application.
Rotating the model: moving the mouse with the left button pressed down.
Rotation may be imagined as if the whole model were embedded into a transparent sphere which is located in a fixed socket. Rotating the model with the mouse approximately corresponds to touching the point of the sphere closest to us with finger, and turning the sphere in the socket by moving the finger. The centre of the virtual sphere is always in the fixed point.
Moving the model: moving the mouse with the right button pressed. The model is moved paralelly to itself in that direction and in such measure where and how far the cursor is moved.
Zoom function: moving the mouse with the left button and the SHIFT button pressed. If the cursor is moved from the side of the graphic area to the center, the model gets smaller, if the cursor is moved from the center of the graphic area to the side then the model gets larger.
Attention ! With zoom only those dimensions of the model are altered, which are to be interpreted in length unit (practically these are the sections depicting the elements). Those dimensions of the model, which are interpreted in other unit than length unit (e.g. formations depicting force and moment vectors) do not change in size with zooming.
Assigning entity: moving the cursor over an entity of the model (finite element, node, force or moment vector, force or moment diagram), then the entity gets in assigned state, its color os changed to the assigning color. (Look at the description of the Display control as well). Features of the assigned entity appear in the Construct window (supposing, that the Planning window is switched on). Moving the cursor farther (away from the entity), the assigned status ceases and values in the Planning window disappear. However, if the left mouse button is pressed when the entity is in assigned state, then the assignment gets fixed and stays regardless the position of the cursor until the ESC button is pressed.
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=== File menu ===
New...
Common function for Windows and Office users. Starts counting the time limit period for the model file.
Open...
Common function for Windows and Office users. At opening, the program checks whether the file about to open can be deleted. If the model file cannot be deleted, it will not open.
Save as... and Save
Common function for Windows and Office users. The model file is saved in a file with .mdl extension. Counting the allowed time period for editing does not restart, neither with Save as... nor with Save.
Close
Common function for Windows and Office users.
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=== View menu ===
Z-view
Similar to General view except that the "Direction" vector need not to be defined, as it is set to (0;0;1) vector, i.e. it is paralell with the Z axis of the workpiece coordinate system and points to the same direction as the positive direction of this axis.
General view
The placement of the workpiece coordinate system (and the workpiece in it) model with respect to the screen can be defined using two vectors: the "View" and the "Direction" vector. Both of these vectors have to be given in workpiece coordinate system.
After executing the "General view" command, the placement of the workpiece coordinate system with respect to the screen is altered such, that the "View" vector become perpendicular to the screen and points towards the user. With this, the workpiece coordinate system is not exactly bound to the screen, as it may rotate around the "View" vector. This rotation is fixed with the "Direction" vector. After executing the "General view" command, looking from the user"s view, the "Direction" vector is vertical and points upward (supposing that the screen itself is not rotated).
The "View" and "Direction" vectors can be entered in the command field with their coordinates. If the entered "Direction" vector is not perpendicular to the "View" vector then it is automatically transformed to the perpendicular projection of itself before executing the command. If the entered "View" and "Direction" vectors are parallel, an error message is generated.
Rotation
By entering "Point 1" and "Point 2" position vectors and an "Angle" into the command field we define a straight section around which the model is rotated by "Angle" degrees. Direction of rotation: looking at the vector pointing from "Point 1" to "Point 2" from the front, the counterclockyise direction is positive. The location of "Point 1" and "Point 2" remains unaltered, i.e. fixed point does not count in this operation.
View plane
The model built with the program is three dimensional, however the graphic interface available for the user (graphic area) is two dimensional. The mouse cursor is traveling on a plane, which normal direction is given by the "View" vector. The "View plane" scalar value defines the signed distance of this plane from the origin of the workpiece coordinate system. The unit of "View plane" is the same as the length unit of the model. Positive value places the plane away from the user's point of view, negative value places the plane towards the user from workpiece coordinate system origin.
Fixed point
The fixed point can be defined with respect to the workpiece coordinate system. This is a point which position is not changed by the rotation operation executed using the mouse. (See also Rotating the model in Handling the mouse section.)
Total image
The zoom ratio and the placement of the model in the screen is changed such that the figure of the model fills the entire graphic area.
Zoom
By left clicking in two different positions on the graphic area, a part of the model is designated, which will be enlarged to fill the graphic area.
Pan
By left clicking in two different positions on the graphic area, a section is defined along which the model is moved. The amount of movement equals with the length of the section.
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=== Settings menu ===
Display control
In the appearing window the user can set which parts (entities) of the model are to be drawn, and by which color.
Switching on and off the display of the respective entities of the model occurs by the setting of the appropriate tick box or pressing or releasing the appropriate button, respectively.
Remarks:
- Switching "Original finite elements" and "Deformed finite elements" to ON excludes each other. "Deformed finite elements" can only be switched on after the calculation.
- By ticking the "Wireframe" tick box the beam elements and the borders of plate elements are displayed.
- By ticking the "Surface" tuck box, the interior of plate elements is filled.
- Switching "Constraints" and "Reactions" to ON excludes each other.
- The "Force and moment diagrams" tick box is disabled, plays informative role.
- The force and moment diagrams of beam elements can be switched on by pressing down the appropriate button under the "Force and moment diagrams" tick box, and switched off by releasing the button. The force and moment diagrams can only be switched on after the calculation. Only one kind of force or moment diagram can be switched on at the same time. If "Deformed finite elements" is switched on, force and moment diagrams cannot be switched.
Clicking on the rectangles on the right side of the window the color of the corresponding entities, the color of the assigned entities and the color the background can be set.
Construct window
Functions:
- entering the features of new entities (finite element, constraint, load);
- displaying the features of the assigned entity;(See Assigning entity as well.)
- modifying the features of the assigned entity.
In certain cases a 
image appears in the left column of the Construct window, beside the name of the parameter. This means that the parameter is associated with a list, wich contains all those values of the parameter which actually occur in the model. By pressing the left and right buttons of the keyboard the value of the parameter is modified based on the list.
In certain cases a 
image appears in the left column of the Construct window, beside the name of the parameter. This means that the parameter is associated with a fixed list, wich contains all possible values of the parameter. By pressing the left and right buttons of the keyboard the value of the parameter is modified based on the list.
Settings
Scaling tab (see figure):
Method of scaling in case of entities which graphic figure appear in force or moment dimension:
Constant vector length: Force and moment vectors do not follow force and moment scale, but appear in constant legth and broken form. Scaling of force and moment diagrams is automatic. Input fields for force and moment scale are inactive.
Automatic scale: Scaling of force and moment vectors and force and moment diagrams is automatic. Small (short) force and moment vectors do not follow force and moment scale, and appear in broken form. Input fields for force and moment scale are inactive.
User defined scale: Scale for force and moment vectors and force and moment diagrams is defined by the user. Az erő- és nyomatékvektorok, valamint az igénybevételi ábrák léptékét a felhasználó adja meg. Small (short) force and moment vectors do not follow force and moment scale, and appear in broken form.
Calculation tab:
Significant digits in arithmetic operations: Specifying number of significant digits for that number representation method, which is used during equation system solving.
Range of (difference between maximum and minimum value between) the order of the elements of reaction matrix: Because of calculation errors (rounding) reactions may be created in such constraints, in which no reactions would arise in case of perfectly accurate calculation. The existence of such reactions may be confusing. If the Applied tick box is checked, then, after calculation, all those reactions are eliminated, which order is smaller than the order of the highest element minus the value given in the input field. (Under this order, all reactions are eliminated, not only those generated by failure, but also those being really part of the result - if any.) Checkong the orders occurs separately for reaction forces and moments, of course. The eliminated reactions are not only disappeared from the graphic field, but deleted from the model itself.
Settings for text file generated automatically after calculation: There is a possibility for saving the input data and the results into a text file after calculation. The text file is saved into the same folder from which the mode file was opened.
No text file: Text file is not generated and saved.
Automatic overwriting: The name of the saved text file is the same as the name of the model (.mdl) file. After every calculation the text file is overritten.
Automatic increment of file name: The name of the saved text file = the name of the model file + positive integer number. Before saving, starting from 1 and incrementing in steps of 1, the program examines which names exist already. Saving will occur under a name with the smallest number, which is not reserved yet.
Whether choosing Automatic overwriting, or Automatic increment of file name the name of the text file can not be specified.
Number format tab (see figure):
Display format of numbers can be chosen for different groups of information.
General format: The number is displayed in ddd,ttt format, supposing that number of digits on the left side of the comma is not more than 15. In the Tenths input field the number of digits on the right side of the comma can be specified. Trailing zeros are not displayed. If the number of digits on the left side of the comma are more than 15, then the number is displayed in normal format.
Normal form: The number is displayed in ddd,tttE±k format. The total number of digits on the left and right side of the comma can be specified in the Displayed digits input field.
Note that the settings on the Number format tab only specify the displaying of the numbers. The number representation (in memory, for calculation) occurss according to the CALCULATION section.
Vector koordinates: Coordinates of vectors in the command field, coordinates of the cursor in the status bar, vector parameters of entities in the Construct window.
Scalar parameters: Scales on the Scaling tab of Settings window, scalar parameters of entities in the Construct window.
Elemets of equation system: Elements of matrices visualized Equation system viewer.
Result text file: Format applied in the text file saved after calculation.
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=== Modify menu ===
Copy
In copying the transformation between the entities to be copied and the copies is translational motion.
Process of copying:
1. The entities to be copied have to be assigned. It can happen by left clicking over the entity or by typing a "V" (finite element) or "K" (constraint) or "T" (load) character followed by the number of the entity into the upper left cell of the command field (e.g.: "V6"). More than one entities can be assigned within one copy process. In the command field the identifiers of the enitites have to be separated by a comma. Clicking again over an alreadi assigned entity or deleting the identifier of the appropriate entity from the command field, the assignment of the entity can be cancelled. The assignment step is closed by pressing Enter.
2. The copy of the assigned entities appears drawn by the assignment color on the graphic area such that the origin of the element which was assigned at first is placed at where the cursor is.
3. The position of the new entities have to be defined by typing an "absolute" or a "relative" vector into the command field. The absolute vector is the position vector of the origin of the copy of the entity which was assigned at first in the workpiece coordinate system. The relative vector is the vector of the translational motion. Whichever from these two vectors have to be given and the copy process closed by pressing Enter.
After executing point 1., by moving the cursor over the graphic area the coordinates of the absolute and relative vectors are continuously refreshed according to the actual position of the cursor.
Erase
The entities cab be deleted by left clicking over the entities, one by one.
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=== Finite elements menü ===
This menu contains the menu points needed to consruct the entities of the model and menu points relating calculation. Entity creation occurs through tje Construct window. Concerning usage see Tervező ablak as well. When creating a new entity the title of the Construct window changes from "Features" to "New entity". After all the necessary parameters were succesfully entered, then the title changes back to "Features". If a parameter is erroneously given, an error message is displayed.
Truss
Beam
In case of beam element the nodes (i.e. the beginning and the endpoint) have to be classified into groups. By the help of groups the rotation degrees of freedom of local nodes of beam elements being connected to each other can be separated. An example is demonstrated on the picture below.
The structure to be simulated is on figure "A". It is composed of four beams, beam 1 and 2 are welded to each other, and so do beam 3 and 4. The sub-structures comprising beam 1 and 2 and beam 3 and 4 are connected by a ball-and-socket joint in node "a". The structure is loaded by the concentraded force designated by the arrow.
It is obviuous that for simulating this structure (at least) four beam elements are needed. Let's lay down that the origin of the local coordinate system of the four beams (i.e. the beginning point of the elements) are placed in node "a". (Choosing the beginning and endpoint is arbitrary, therefore we can do it whitout any consequence.)
Truss element cannot be used for simulating the structure as "welded" connection (continuous material connection) is not possible to create whit that. However, continuous material connection would be automatically cretaed with beam elements by placing nodes into same position - without utilizing groups. This model would simulate the structure presented in figure "B", which is not the same than the structure to be simulated as all the four elements are rigidly connected to each other in point "a".
The ball-and-socket joint between the sub-structures can be created by classífying local nodes placed in point "a" into different groups. Elements which local node in point "a" is classifyed into the same group are rigidly connected to each other in point "a". Sub-structures classified into different groups connect to each other with ball-and-socket joint; their displacement degrees of freedom are common, rotation degrees of freedom are not. Groups are designed by positive integer numbers, maximum 255 groups can be defined per global node.
In the current example, for simulating the structure presented in figure "A", one has to classify the beginning points of elements 1 and 2 (which is lying in point "a") into e.g. group "1" and the beginning points of element 3 and 4 into e.g. group "2". These numbers have to be written into the "Group of beginning point" field of the Construct window.
If all the beginning points of the four elements are classified into the same group - i.e. the same number, e.g. "1", is written in the "Group of beginning point" field for all the four elements - then the model conforms to the structure on figure "B".
In case of beam element, one has to enter the direction of the Y-axis of the local coordinate system with respect to the global coordinate system. Thus, that principal axis of the cross section of the beam is directed to which the area moment of inertia Iyy is related. Direction of the Z-axis yields automatically. In the local coordinates system of the element beam, the Y and Z axes coincide the principal axes of the cross section, it has to be taken into consideration when entering the inputs.
The direction of the Y-axis is stored as a unit vector, but entering it as unit vector is not obligatory during data input or data modification. The vector entered is automatically converted to a unit vector, which is parallel with and points to the same direction as the projection of the entered vector to a plane perpendicular to the local X-axis. If the entered vector does not have a projection perpendicular to the X-axis, an error message is generated.
Constant strain triangle
Triangular bending element
The construct window is identical to that in case of CST element except that the 
input field appears. This is a two state switch. In the local coordinate system the rotation degrees of freedom around Z-axis do not exsist. In genereal case the global (workpiece) coordinate system is not identical to the local one, therefore rotations have to be extended to three dimensions and local stiffness matrix has to be expanded accordingly; thus the size of the stiffness matrix will be 18x18. In local coordinate system, rows and colums corresponding to rotations around Z-axis contain zeroes in "Off" state of switch, and the terms given in KT matrix on page 92, Bojtár-Vörös [7] in "On" state of the switch.
Editing a node
Nodes can not be created directly. Nodes are automatically generated by creating finite elements. After displaying the properties of a node in the Construct window, there is a possibility to define a nodal coordinate system. It is needed if such a constraint is necessary which is not parallell with any out of the X, Y and Z axes of the workpiece (= global) coordinate system.
Displacement constraint
The "Direction" of the constraint must be paralell with one of the axes of the nodal coordinate system. Therefore, the possible directions are: x,-x,y,-y,z,-z. Directions differing only in sign are not substantially different. Sign is the free coice of the user, however it is to be noted that the this sign is applied to the number entered as the "Value" parameter.
At most one displacement constraint can be applied paralelly to each axes of the nodal coordinate system, i.e. maximum three displacement constraint can be applied per node.
With the "Value" scalar parameter, one can define the amount of displacement of the node along "Direction". In general, constraints simulate a support and 0 (zero) has to be given for "Value", as the support fixes the displacement of the node. It may happen however, that the loading of the structure comes from the displacement of one (or more) node; in such case the amount of this displacement has to be given.
Rotation constraint
The same applies to rotation constraints as written in case of displacement constraint, except that different rotation constraints can be applied to different groups. Therefore the maximum number of rotation constraints per node is the number of the groups of the node times three.
Describing of groupsis given in the explanation of the beam element.
Concentrated force
The point of application can only be a node.
The direction of the concentrated force has to be given in nodal coordinate system.
Concentrated moment
The point of application can only be a node.
The direction of the moment has to be given in nodal coordinate system.
Calculation
The calculation is executed.
The description of the model and the results are saved into the result text file.
The value of elements of the stiffnes matrix, the deformation vector (nodal displacements and rotations), the load vector and the reaction vector can be viewed in the Equation system viewer window.Nodal displacements and rotations are presented in nodal coordinate system in the equation system viewer, whereas in the result text file these are saved in workpiece (= global) coordinate system.
The force and moment diagrams and the deformed figure of the model can be visualized using Display control.
Calculation results can not be saved into the .mdl file. After closing the program, the calculation results are lost (excluding the result text file), and can only be recreated by opening the model (.mdl) and executing the calculation again.
After calculation the program turns from "Model building" to "Evaluation" mode. Some functions needed for model building are not available in "Evaluation" mode and vice-versa. If case of an intention to modify the model, one has to return to "Model building" mode by left clicking on the "Model building" panel in the status bar. By clicking on the "Model building" panel, calculation results are lost.
Equation system viewer
The format of numbers displayed in Equation system viewer can be defined on the Number format tab of the Settings window.
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