In modern earthquake engineering, design for seismic isolation has become increasingly important for the prevention of devastating damage in a major earthquake. One effective and practical method for seismic isolation is the use of friction pendulum bearings, of which many may be used in a bridge structure.
Hydroelectric power plants are used for economic and environmentally friendly electric power generation all around the world. One of the technical challenges in the design of such structures is to consider the fluid-structure interaction effects. For example, when the water pressure fluctuates as it passes through the fluid passage and the hydraulic turbine, it creates a pulsatile loading that causes vibration of the powerhouse structure. Displacement (magnified) In this blog post, we present some results of a study dealing with the vibrations of a powerhouse structure due to the fluid-structure interaction, obtained using ADINA. Figure 1 depicts a schematic of the powerhouse structure, the fluid passage, and the turbine. Figure 2 shows the finite element model of the coupled system. The nonlinear transient response of the coupled system was solved using 3000 implicit integration time steps, with a time step of 0.002 seconds (see Ref). The fluid was modeled as a Navier-Stokes fluid. The turbulent behavior of the fluid was modeled using the shear stress transport (SST) model. The sliding mesh boundary condition was used to incorporate the large rotations of the turbine blades. Figure 1: Schematic of the powerhouse Figure 2: Finite element mesh of the (a) powerhouse structure
The California Department of Transportation (Caltrans) initiated the California Toll Bridge Seismic Retrofit Program to determine the vulnerability of California’s major toll bridges to damage associated with strong earthquakes and to design retrofits to improve seismic safety. ADINA was selected by Caltrans and contractors in this Retrofit Program. A very important part in the bridge analyses is the modeling of the braces in the bridge structures (a photograph of the San Francisco-Oakland Bay Bridge is shown below). Typical braces, which are laced built up members with rivets, were tested in the laboratory. Since there are many such braces in each bridge structure, it was necessary to establish a simple and effective finite element model of a typical brace. In the following we briefly describe, courtesy of SC Solutions, California, the modeling and verification of the behavior of these braces using the ADINA moment-curvature beam elements. This ADINA capability has proven to be of major importance for the nonlinear analyses of bridges. For the verification study, braces subjected to axial and flexural stresses were modeled in detail with shell elements, and then simplified with the moment-curvature beam elements in ADINA. The following figures show that a drastic reduction in degrees of
In response to customers’ requirements, ADINA supports the Bergström-Boyce and Three-Network viscoelastic material models.
ADINA is used worldwide for complex analyses. The Southwest Jiaotong University conducted an analysis under contract to study the structural integrity of the roof of a large railway station at Hohhot, Inner Mongolia, in China.