The above animation depicts an axisymmetric model of a mono-tube gas shock absorber, with its schematic beside it. The piston inside the casing pushes its way through the oil (the hydraulic fluid which in reality is a mixture of oil and gas) creating resistance as the oil is pushed through the small holes in the piston. The contact between the piston (solid model) and the casing is modeled by specifying a friction coefficient, which is usually very small due to the lubrication provided by the oil. The spring is initially extended and then released. Its subsequent motion is damped by the oil flowing through the holes in the piston. The figure below shows the acceleration of the piston during a 0.2-second damping event.  

FSI (fluid-structure interaction) analysis has many applications in the automotive industry such as the analysis of shock absorbers and valve mechanisms. In the ADINA System, the ADINA-FSI program provides fully coupled analysis of fluid flow with structural interaction problems, meeting the needs of automotive and other industries.

Nonlinear cyclic symmetry analysis is a new feature in ADINA 8.1 that can be used for static, dynamic and frequency analyses. In static and dynamic analyses, the loads applied to each cyclic part must be identical (when rotated around the cyclic axis). In this case, called periodic symmetry, most nonlinear features available in ADINA can be present (including contact, plasticity, deformation dependent centrifugal loads). Nonlinear cyclic frequency analysis can also be performed after a periodically symmetric static or dynamic analysis. In this case, the frequencies and mode shapes of the deformed structure can be obtained at a fraction of the computational time and storage space used without this option.

The new surface tension option is implemented in the ADINA program, version 8.0. This new option allows the user to assign a surface tension value to selected lines (for 2-D planar and axisymmetric problems) or surfaces (for 3-D problems). The surface tension option can be used even if the boundaries undergo excessive deformation. This feature is useful in accurately modeling viscous materials such as cells, living tissues and heated glass. The effect of surface tension is also significant in MEMS sensors/actuators and other small-sized devices.

One interesting feature in the ADINA 8.0 version is the bolt option. A pre-stress beam (pipe) element with a given constant force creates a bolt element. Constant pre-stressing is assured by imposing an initial iteration scheme, during which (under no other, external or internal load condition) the pre-stressing force remains unchanged even if the structure deforms. 

The new surface tension option is implemented in the ADINA program, version 8.0. This new option allows the user to assign a surface tension value to selected lines (for 2-D planar and axisymmetric problems) or surfaces (for 3-D problems). The surface tension option can be used even if the boundaries undergo excessive deformation. This feature is useful in accurately modeling viscous materials such as cells, living tissues and heated glass. The effect of surface tension is also significant in MEMS sensors/actuators and other small-sized devices.

Hydraulic engine mounts are used to reduce automotive engine vibration and noise. The performance of the hydraulic engine mount due to variations in the excitation frequency and amplitude is of interest to the designer.

The animation shows the dynamic analysis of a simplified piping system, similar to those used in nuclear power plants. The analysis is performed using the ADINA subsonic potential-based fluid elements to model the water in the pipe and the ADINA 4-node shell elements (MITC4 elements) to model the pipe walls.

Mass flow rate, , is the mass of fluid passing through a boundary per unit of time. It is defined as: