ANSYS STRUCTURAL: Truss Bridge Static Simulation

In this project, we performed a structural simulation of a Truss Bridge in ANSYS Static Structural.

What are Truss Bridges?

Bridges are structures built to carry traffic loads safely from one side to the other and cross over ths obstacles, such as roads, rivers, valleys, or railways. Truss bridges are designed with straight structural members arranged in a repeating triangular pattern, so that the members can carry the load mainly through tension and axial compression rather than bending. They are widely used bridges because of a very high stiffness and load capacity with a relatively low self-weight.

Geometry Definition:

We modeled the geometry of the computational domain with Design Modeler software. The computational domain corresponds to a truss-type bridge in which a flat rectangular plate is constructed from triangular trusses, creating the triangular arrangements.

Mesh:

We meshed the computational domain to create a discretized domain. An unstructured grid was created, so that about 22,786 elements were generated.

ANSYS Static Structural:

There are different solvers and software available for users for structural modeling. For the present simulation, we utilize the ANSYS Static Structural Solver. The overall procedure and main steps required for static structural simulations include the definition of materials, connections, different types of boundary conditions, and post-processing.

How to define boundary conditions?

It is assumed that a uniform pressure load is applied to the plate. This uniform pressure load is applied vertically downward to the bridge body, representing the weight of the structure and the traffic passing over it, such as vehicles. Next, we defined a fixed support boundary condition on the two transverse edges at the beginning and end of the bridge structure. This constrained the bridge body from movement with no degrees of freedom.

What is the purpose of this simulation?

This investigation aims to evaluate the structural response of the truss bridge under loading and study the solid behavior with analysis of distributions of the total deformation, elastic strain, and von Mises stress.

Results and discussions:

The total deformation distribution indicates that maximum deflection occurs in the middle regions of the bridge due to pressure loading, while the two edges at the beginning and end of the bridge structure remain fixed. The stress distribution indicates that the maximum stress appears near the fixed support at the two transverse edges, while the stress decreases toward the middle zones.