Applications - Other Analysis

Bra analysis

The search for a bra with a perfect fit has been made by many women over the years. However, until recently there has been little application of engineering to bra design despite an early patent brought by an aeronautical engineer. In fact, the basic design has not changed dramatically since its appearance in 1885. In the past year there has been an emergence of interest in designing the perfect bra.

Most recently it became the subject of a program broadcast on UK TV Channel 4 on the 24 June 1998. 'Designs on Your Bra' followed London based industrial designers, Dick Powell and Richard Seymour, as they attempted a radical redesign of the bra.

They were assisted during the project by the consulting engineers, Arup's Advanced Technology Group, who were able to give an insight into the engineering performance of the bra using advanced computer techniques.

Heart valve analysis

Bioprosthetic heart valves mostly fail from either tearing of the leaflets, calcification, or a combination of both. The exact mechanism of this calcification is unknown but it is strongly linked with areas of high mechanical stresses.

In conjunction with Sheffield University a non-linear material characteristic based on an exponential strain energy density function has been developed for soft tissues in LS-Dyna and implemented for solid, shell and beam elements.

Using LS-Dyna with this new material model, the closing and opening motion of linear and non-linear models of bioprosthetic heart valves has been analysed and compared over the entire cardiac cycle.

The differences in the behaviour of a linear and a non-linear material model can be seen in the animations below.

The valve shown on this page is based on a bicuspid bovine pericardial bioprosthetic valve. LS-Dyna has also been used to model tricuspid porcine bioprosthetic valves and to model the aortic root.

Work is currently in progress modelling heart valves using the coupled fluid-structure capabilities of LS-Dyna.

Impact tests on electronic products

• Electronic products (mobile phones, pagers, portable computers) can be designed against accidental damage.
• Examples of accidental damage are:
  • Dropping equipment on the floor.
  • Sitting on equipment.
  • Spilling tea on equipment.
• These products can also be designed such that in the case of accidental damage certain components act as energy absorbers. These damaged components can then be economically repaired or replaced.
• The pictures below show a finite element model of a generic pager being accidentally dropped from 2m. The impact event was simulated using LS-Dyna.
• The model is capable of predicting the stresses and strains experienced by the pager components during the impact event.
• An efficient and economical design of these products can be achieved using computer simulations where the designs can be confidently tested to the required design targets.

LS-DYNA, LS-OPT and LS-PrePost are registered trademarks of Livermore Software Technology Corporation.