Spent Fuel (SF) storage racks are fully submerged in water and stand freely at the bottom of the Spent Fuel Pool (SFP). The water column acts as a coolant for residual heat removal from nuclear fuel and provides radiation shielding. Due to the storage of large quantities of nuclear material, Appendix D to NUREG-0800 Section 3.8.4 [1] specifies that the functionality of the SF racks be demonstrated for the D + L + Fd load combination, where Fd is the force caused by the accidental drop of the heaviest load from maximum height. D and L are the dead and live loads acting on the SF racks.
Modeling drop tests of various goods has always been one of the classic problems for explicit structural dynamics. Current requirements for such tests often require the consideration of multiple sequential impacts, such as the procedures described by the International Safe Transit Association. CADFEM is investigating the possibilities of automating such sequential drop tests in the Workbench LS-DYNA environment. With the automated calculation of sequential drop tests, these can be integrated into optimization cycles.
With the enforcement of the revised Road Traffic Act, wearing helmets has become a mandatory effort for all cyclists since April 1, 2023 in Japan. However, there are still many people who do not wear helmets. Therefore, we considered developing a foldable helmet that can be easily carried by applying the concept of origami engineering. Origami engineering is a research field proposed with the aim of developing lightweight, high-strength structural components based on the idea of origami, a traditional Japanese paper craft in which various shapes are created by folding paper-like materials. Under the same conditions of the safety test for industrial helmets, a 5 kg striker was dropped from a height of 1.0 m onto a dummy head wearing the hat in which impact energy absorption material was installed, and the impact load received by the dummy head was computed in the simulation. As a result, it was confirmed that it was possible to reduce the impact load by devising the proper material properties and folding shape.
The use of electronics in harsh environments has increased significantly in the past few decades. For example, in automobiles, where electronic assemblies experience wide temperature extremes, temperature cycling, and shock, the cost of electronics was 18% of the total vehicle cost in the year 2000 and 40% of the total vehicle cost in 2020 [1]. Automotive electronic assemblies experience mechanical shock in a variety of scenarios such as a door slam, a vehicle crash or going over a pothole. In addition to the impact of component power dissipation on component temperatures, the automotive environment can include significant temperature variation due to diurnal solar loading, climate control, and engine heating/cooling cycles. The solder joints that connect electronic components to circuit boards are common failure locations in electronic assemblies, particularly in high shock/vibration environments and extreme temperature cycling conditions. Solder joint failure behavior is heavily influenced by the component’s package construction and materials.
For obvious security reasons, wearing a helmet is highly recommended when riding a bike or a skateboard. In order for the manufacturers to design safe helmets some regulations have been established and must be respected before any market release. The process enabling to meet the regulation targets can be quite long considering the numerous impact points and test configurations that have to be repeated for each helmet size. The use of simulation and the appropriate tools can be a real asset to save time and reduce experimental tests while increasing security and comfort. Indeed, the numerical simulation offers the opportunity to explore more designs and test almost an infinite number of impact configurations. Especially when the numerical tools are powerful enough to significantly speed up the product development process.
The cost-sensitive development project for a new sewing machine series within Bernina International AG includes optimizing the packaging to the new logistical conditions and adapting it to the new product design. Packaging protection also had to be increased. Regarding specifications, no acceleration forces more significant than 100G may occur on the machine during a standardized drop test from a height of 0.9m. Furthermore, polystyrene should be reduced by at least 20% for cost and environmental reasons. For the end customer, the package should be easy to transport by hand and leave a tidy and logical impression when unpacked, which was difficult to specify and led to some loose ends concerning the arrangement of accessories.
Accidental Fuel Drop on Spent Fuel Pool Storage Racks