This example shows further results of a helmet impact analysis (courtesy of MET S.p.A., Italy). This time the head and helmet both have an initial speed of 5 m/s and side-impact a rigid anvil. This is one of several impact tests that MET uses to evaluate their new helmet designs. The results of another analysis compared with laboratory test results were presented some time ago. The objective of the analysis is to ensure that the helmet provides adequate protection for the head. ADINA is used to check that the deceleration of the head does not exceed 250g, and that the stresses in the helmet do not exceed the capacity of the material. More information can be found in a previous News. The animations above and below show a simplified aeroengine disk with 30 blades connected to the disk using dovetail attachments. A large deformation periodic static analysis is first performed where the centrifugal force leads to contact between the blades and the disk (above animation). The frequencies and mode shapes of the whole disk-blades assembly are then obtained using frequency analysis with cyclic symmetry. This frequency analysis accounts for the deformed geometry, the initial stresses, the contact constraints and the spin softening

ADINA is known for its powerful capabilities in the solution of fluid structure interaction (FSI) problems. For many years, ADINA FSI solutions have been used successfully for many applications in a wide range of industries.   Although ADINA FSI is a powerful tool for many problems involving structures and fluid flow, there are certain classes of problems involving structures and fluids that do not require the use of ADINA FSI but can be solved effectively through a purely structural analysis. An example of such problems is the analysis of fluid-filled cavities inside a solid or structure. In this Tech Brief, we demonstrate the use of the hydrostatic fluid feature in ADINA Structures that can be used to model the pressure and volume variation in cavities filled with compressible fluids. An example of such application is the simulation of a compressed fluid-filled rubber capsule as shown in the animation above. For the hydrostatic fluid model, it is assumed that the fluid pressure in the cavity is uniform at any point of time. The model only requires the hydrostatic fluid pressure to be applied on the internal surface of the cavity, with no material definition required. The variation of the hydrostatic fluid

Blow molding is a process frequently used to manufacture hollow plastic objects such as bottles and tanks. A molten plastic tube (parison) is extruded into the mold and pinched at one end. Compressed air is then blown into the parison cavity, which takes the shape of the mold. As the material properties of the parison are highly temperature dependent, the heat exchange between the parison and the blown air is very important during the process. The thermal coupling capability of ADINA-FSI allows the modeling of such conjugate heat transfer effects. The animation above depicts an axisymmetric blow molding simulation using ADINA-FSI. The parison is modeled as a temperature-dependent viscoelastic material undergoing large displacements and large strains. The internal part of the mold is modeled as a contact surface and the compressed air is injected using a time-dependent normal traction boundary condition.  

Bolts are an integral part of engineering designs, and bolted structures can show a complex mechanical behavior. Not long ago, bolted structural parts were commonly treated as rigidly connected. With recent advances in computer-aided modeling and finite element analysis, engineers can now get insight into bolted connections that was previously difficult to obtain. Engineers can ask questions regarding, e.g., the bolt forces required to prevent leaking of fluid, the frequencies of a bolted structure when contact and friction play an important role, and the contribution of the bolted connections to noise and vibration. Also, there are often many bolts in assemblies that need to be tightened in a certain sequence. With the practical requirements of today’s design engineers in view, the bolt modeling capability in ADINA allows bolt tightening specified either by a force value or by a bolt shortening. The program allows bolts to be tightened in a specified sequence in order to model the actual assemblage process. To illustrate the ADINA bolt option, we present a typical bolt-type problem, a mount of an axle used in heavy machinery (courtesy of John Deere). A panoramic view of the assembly is shown in the movie above. 10-node tetrahedral elements are

In fluid flow analysis, we ideally can use relatively coarse meshes and still get reasonable solutions in the flow and pressure predictions, even for high Reynolds and Peclet number flows. We would also like to have a true consistent tangent matrix in the Newton-Raphson iteration. This is particularly important in FSI solutions where large deformations in the structure and the fluid mesh can occur. Of course, if the fluid mesh is increasingly made finer, the flow and pressure predictions will become increasingly more accurate. Here we present the solutions of simple test problems to illustrate the power of the new elements. Note that these are only test problems. Left: Coarse Mesh   Right: Fine Mesh Re = 1 Re = 100 Re = 10,000 Re = 1,000,000 A Laminar Cavity Flow model The laminar cavity flow model depicted shows particle-tracing results for Reynolds numbers 1, 100, 10 000 and 1 000 000. This is an example of hierarchical modeling using the new Flow Condition Based Interpolation (FCBI) elements in ADINA-F. Hierarchical modeling means “assume first laminar flow conditions.” The figures show that a reasonable solution is obtained using a coarse mesh. When the mesh is made finer, more details of the