S. Saha, A. Ramirez, C. DiBiasio, M. Culpepper
Massachusetts Institute of Technology, Cambridge, MA, USA
Charles Stark Draper Laboratory Inc., Cambridge, MA, USA
Introduction: Flexures are low-cost bearings that are capable of providing motion guidance with high repeatability and low friction (Figure 1). However, applications of flexure bearings are often limited by their low range. This is because motion guidance in flexures is provided by bending/flexing of members; thus, range is limited by the bending stiffness. As the bending stiffness can be ...
Numerically Closing the Loop of the Adaptive Optics Sensor: the Validation of the COMSOL Multiphysics® Simulation - new
C. Del Vecchio, R. Briguglio, A. Riccardi
National Institute for Astrophysics, Arcetri Astrophysical Observatory, Florence, Italy
As any other modelling of a physical behavior, the numerical simulation of the mechanical response of an adaptive secondary mirror requires that the results match the experimental data. Such an agreement was recently demonstrated for the local mirror stiffness of the LBT and VLT Deformable Mirrors; a reliable modeling is a good tool for the extrapolation of the missing optical data (spider ...
G. Maizza, R. Cagliero, and A. Santoro
Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Torino, Italy
Powder metallurgy is a key technology for manufacturing advanced components based on TiAl alloys. Cold compaction is the primary step to produce green parts. Cold deformation of TiAl powder is difficult due to its typical poor ductility. Plastic deformation and cracking susceptibility of TiAl powder strongly depends on micro-mechanical phenomena. To manage real compaction problems more reliable ...
Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
The fundamental frequency and the corresponding damping value are the main design parameters for footbridges against excessive vibrations induced by pedestrians. Since pedestrians typically walk at a pace of 1.6–2.4 Hz, this frequency range as well as the range of the second harmonic, namely 3.5–4.5 Hz, should be avoided. However it has been observed that the fundamental frequency of a bridge ...
S. Newbauer, D. Cook, and D. Pettis
Milwaukee School of Engineering
Designing a component with multiple functions, e.g. load bearing and noise attenuation, can increase the effectiveness of each component and reduce the complexity of the overall system, thereby improving system efficiency as well. Current multifunctional components include metal foam. It is posited that the cellular pores of the metal foam can be engineered and optimized for desired ...
L. Teresi, V. Varano
LaMS - Modelling & Simulation Lab, Università degli Studi Roma Tre, Roma, Italy
Nematic Elastomers (NEs) possess both the elastic properties of rubbers and the orientational properties of liquid crystals. Those two properties makes the configuration of NEs very sensitive to isotropic-nematic phase transition. Our goal is to replicate with numerical experiments the phenomena of shape formation in Twist-Nematic Elastomers (TNEs): a flat bar evolves into a helicoidal shape ...
Università degli Studi di Milano Bicocca, Milano, Italy
We present numerical models and field data that aid understanding of volcano-tectonic processes related to the propagation of inclined sheets and dykes under a stress field resulting from the inflation of a shallow magma chamber. Structural field data from the classical Cuillins cone-sheet complex (Isle of Skye) show that sheets have a constant average dip angle (45°), with pure dilational or ...
Numerical and Experimental Analysis of Natural and Mixed Convection Heat Transfer for Vertically Arranged DIMM
G. Petrone, and G. Cammarata
University of Catania, Catania, Italy
It is commonly recognized that careful thermal design of electronic equipments represents an unavoidable pre-production step in order to ensure reliability and performance of those components during their functioning. This paper mainly concerns a comparison between experimental and numerical results obtained in studying thermal dissipation in natural and mixed convection conditions for RAM ...
Optimization of a High-Temperature High-Pressure Direct Wafer Bonding Process for III-V Semiconductors
R. Martin, J. Kozak, K. Anglin, and W. Goodhue
University of Massachusetts Lowell
Many optoelectronic devices utilize a heterojunction of a pair semiconducting materials including high-efficiency MEMS devices, solar cells, LEDs, and VCSELs. One fabrication technique which achieves such a device is direct wafer fusion. To optimize the process, COMSOL Multiphysics 4.0 was used to test various geometric configurations of the fixture. 2D and 3D models were created in order ...
M.S. Yeoman, A. Cizinauskas, C. Lowry, G. Vincent, S. Collins, D. Simpson
Continuum Blue, Tredomen, Ystrad Mynach, United Kingdom
Corin Group, Cirencester, United Kingdom
Imoprhics, Manchester, United Kingdom
Bone resorption around hip stems, in particular periprosthetic bone loss, is a common observation post-operatively. A number of factors influence the amount of bone loss over time and the mechanical environment following total hip replacement (THR) is important. Conventional long stem prostheses have been shown to transfer loads distally, resulting in bone loss of the proximal femur. More ...