Bridge Simulator Hardware Development

Bridge Simulator Hardware Development

1. Bridge Description
FEA bridge is made based on miniature steel frame bridge, the geometry of the steel frame bridge can be seen in the following figure 1.

bridge frame
Figure 1. Geometry Bridge Steel Frame (in cm)

The steel frame comprises a 3cm elbow profile with 1.5mm thick, and a steel plate as a vehicle floor with 2.5 mm steel plate thickness. Connect plate using plate with 4mm kebetabalan, with 8mm diameter connector bolt.

 

2. FEA Bridge Simulation
FEA models and simulations of miniature steel frame bridges are performed using the 2015 CSi Bridge application. The details of the modeling will be described as follows.

2.1 Model Element Development
There are two types of elements in the bridge miniature model, the steel frame defined as the frame element, and the steel plate defined as the element area of ​​the FEA model (See Figure 2).

steel frameSteel flat

(a)                                                                                            (b)

Figure 2.  (a) Steel Frame For Element Frame In FEA Model and (b) Steel Plate In The Element Area In FEA Model

 

2.2 Element Properties Definition
The properties of each element can be defined in the FEA model. In this miniature bridge, frame material is used in the form of elbow steel, and steel plate. The material properties used in the FEA model can be seen in the following Table I.

Table steel

 

 2.3 Model Element Construction
Each frame and plate elements are then arranged according to the geometry of the bridge miniature. The plate element is connected to the steel frame structure through the nodal point at the end of the frame element on the steel frame structure. The connection to the steel frame structure on the bridge miniature is connected by bolts, so in the FEA model it is assumed that the connections of each frame do not withstand the rotation (pin connection). FEA model elements consisting of frames and plates that have been prepared are as Figure 3.

Figure 3

Figure 3.  Finite Element Bridge Model

 

 3. Loading
The loading on the miniature bridge consists of static loads which are the bridge’s own weight (steel frame frame and steel plate) and rubber sheet (7 kg / m2) placed on a steel plate. In addition to static loads, miniature bridges are also provided with moving vehicle loads from the Scania remote control scale of 1:14. Miniature bridge placement using joint-roll placement.

Figure 4

Figure 4. FEA Bridge Placement and Sensor Location

 

4. Bridge Model Analysis
Some analyzes of the FEA Bridge model are carried out with some variation in truck weight and speed, mimicking the conditions on the miniature bridge in the laboratory. The work of bridge model analysis will be explained as follows.

4.1 Static and Dynamic Analysis
After making the FEA model of the bridge, a static analysis was performed on the miniature bridge. From the static analysis, the miniature bridge was able to withstand its own weight and live load (a point load) of 300 kg in the middle of the bridge span. While the largest stress ratio that occurs on the steel frame is 0.848. So the bridge is able to withstand the static load that occurs.

Figure 5

Figure 5.  Stress Ratio On Static Analysis Miniature Bridge.
As for dynamic analysis, bridge response analysis is done due to moving vehicle load. Acceleration data from FEA miniature bridge due to moving vehicle load can be seen in the following Figure 6.

Figure 6

Figure 6.  Dynamic Model of FEA Bridges Due to Moving Vehicle Expenses.

 

4.2 Frequency Analysis
Frequency analysis is also carried out by taking the natural frequencies of each mode that occur in the FEA model of the bridge. Frequency analysis will be used to validate the FEA model of the bridge. From frequency analysis results on CSi Bridge, natural frequencies are generated in the first 4 (four) modes of the FEA model of the bridge which can be seen in the following Figure 7.

Figure 7

Figure 7. FEA Bridge’s Mode Shape.