Visualisation of a Simple Beam under a Load in Virtual Environment

Visualisation is generally considered to be a problem in structural design. Being an iterative process, structural design is time consuming for engineers, and results are difficult for clients to visualize. Current numerical methods have slow dynamic visualisation capability, which is usually separate from the calculation phase. This paper investigates whether an analogue virtual reality (VR) model of a structure can integrate calculation and visual representation. Early results of this research show that it is possible to have analogue virtual reality models of structures capable of real time user interaction. The paper shows how the user can interact with a VR analogue model of a simple beam, move a concentrated load along the length of the beam, change the value of the force, and visualise deflection of the beam using the analytical solution of the problem. 1: Virtual beam model The geometry of the vis ual beam object was defined as an element with a finite number of cross sections. The force was presented as an arrow shape, indicating the direction and orientation of the vector on the screen. The VR visual beam model divided in 10 segments is shown in the figure 1. The parameters adopted for the model were based on the properties of steel. Consequently, the force was calibrated to be capable to make significant deflection of the steel simple beam, to make the visualisation easier. Figure 1 The VR visual beam model of a simple beam of length L = 10 m, height h = 1 m, depth d = 1m, Young’s modulus E = 207 GN/m, second moment of area I = 0.0833333 m, with application of a vertical concentrated load of F = 250 MN at position of x = 6.506 m from left support of the beam and with displayed values of deflection for each cross-section between segments When the cursor is over the force, dragging the arrow changes the value of the force proportionally to the dragging distance and within a range between a maximum and minimum value of the force. The value of the force is displayed by the arrow interactively. At the same time, the colour of the arrow changes proportionally to the force from blue for zero, to red for maximum value. For the model shown in the figure 1, the maximum value of the force is F = 250 MN, which corresponds to the red colour of the force. Also, the position of the force was programmed to have a left and right limit of motion, which covers all the length of the beam. The force in the model shown in the figure 1 was designed to move from the left support of the beam with co-ordinate x = 0 m, to the right support of the beam with co-ordinate x = 10 m. The communication between the two objects, the beam and the force, is based on information exchange between them. The value and the position of the force on the beam, is sent to the visual beam object. The visual beam is designed for displacement of defined cross sections using the analytical solution for deflection of the simple beam as function of the position of the force, obtained from the classical solution in the field of Strength of Materials [1]. Let us consider a section of the beam a distance z from the left support of the beam. When the vertical force is at a distance "a" from the left support of the simple beam, the deflection of the cross sections between the left support and vertical force (for z < a) is given by: For the same position of the vertical force, the deflection of the cross sections between the vertical force and right support (for z > a) is given by: