Automated resolution of the spiral torsion spring inverse design problem.

Many mechanical applications take advantage of spiral torsion springs due to their robustness, compactness, and simplicity. Brand-new manufacturing methods allow to create spiral springs with unconventional geometries and materials that suit a wider range of uses demanding either linearity or nonlinearity. Designing a spiral torsion spring with a nonlinear desired torque curve may be a great challenge, due to their many degrees-of-freedom (length, width, thickness, arbor, and barrel diameters, etc.

An enhanced whole-body vibration emission index for railway vehicles.

Whole-body vibration (WBV) is a concept that is gaining importance in the railway sector. Occupational disorders, such as back pain and sciatica, frequently cause sick leave and have resulted in lawsuits against employers. Railway operators require a clear procedure for specification and purchase of certified rail vehicles that evaluate the vehicle from the point of view of the effect of WBV.

Rapid Prototyping of Personalized Articular Orthoses by Lamination of Composite Fibers upon 3D-Printed Molds.

Advances in additive manufacturing technologies and composite materials are starting to be combined into synergic procedures that may impact the biomedical field by helping to achieve personalized and high-performance solutions for low-resource settings. In this article, we illustrate the benefits of 3D-printed rapid molds, upon which composite fibers can be laminated in a direct and resource-efficient way, for the personalized development of articular splints. The rapid mold concept presented in this work allows for a flexible lamination and curing process, even compatible with autoclaves.

Author Correction: Epoxy toughening through high pressure and shear rate preprocessing.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Epoxy toughening through high pressure and shear rate preprocessing.

We have successfully conceived and demonstrated a simple, scalable process for improving the fracture energy of epoxy resins. The process is based on the combined application of high pressures (in the order of GPa) and shear rates (in the order of 10 m) in the pre-cured polymer, obtaining mechanical forces sufficiently high to increase the reactivity of the monomers due to the scission of the epoxy groups. To achieve these high values of pressure and shear rate, we take advantage of the elastohydrodynamic phenomena occurring at lubricated higher kinematic pairs as, for example, the rolling element - track pair in ball bearings.