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Mechanical nonlinearities (Geometric or Contact) in inertial MEMS sensors
Mechanical nonlinearities play an important role in inertial MEMS sensors and cannot be avoided. The trend to push the performance to the limits caused second-order nonlinear effects to become a critical phenomenon that must be considered: these effects are already visible and characterized on mass production devices. External shocks and vibrations could also induce other Read more
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Experimental characterization of nonlinear motion of MEMS resonators
Mechanical nonlinearities play an important role in inertial MEMS sensors, in particular due to geometrical and process constraints. The trend to push the performance to the limits caused second-order nonlinear effects to become a critical phenomenon that must be taken into account: these effects are already visible and characterized on mass production devices. Several methods Read more
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Out-of-plane stroboscopic analysis of MEMS motion sensors
Goal: implement a system for optical stroboscopic analysis of TDK’s MEMS accelerometers and gyroscopes, aimed at the characterization of out-of-plane resonant modes in those devices Strategy: enhance TDK’s existing system for in-plane stroboscopic optical analysis, based on the usage of infrared microscope and synchronously controlled light source, to add the out-of-plane capability. Work phases Estimated Read more
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Design of a metamaterial for a novel MEMS mechanical circulator
Several works in literature and from our research group have shown that periodic structures with space-time varying properties lead to a non-symmetric (non-reciprocal) response. In short, in some frequency intervals (band gaps), these metamaterials allow the propagation of waves only in one direction and block them in the opposite direction. This thesis aims to design Read more
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Active & passive meta-MEMS devices for signal processing
During this thesis, the student will design a multifunctional metastructure at the micro-scale, where a tailored arrangement of unit cells allows performing certain operations to an incoming elastic signal. Examples that we want to explore are (i) performing derivative/integrals and arbitrary transfer functions, (ii) frequency conversion, (iii) Wave-diode effect (nonreciprocity), (iv) waveguiding, trapping and focusing. Read more
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Substructuring techniques and pROMs for the optimization of a MEMS voice recognition device
This thesis aims to develop strategies to alleviate the computational burden of optimising a novel, purely mechanical voice recognition device. The device is composed of many repeated cells, each slightly varied through parametric optimisation of a high-fidelity finite element model with millions of degrees of freedom. Direct simulation of such models is computationally prohibitive, making Read more
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Design of MEMS structure for adhesion characterization
Stiction is a critical phenomenon in MEMS structure which consists in the movable MEMS structure being unable to release from fixed structure when engaged. Stiction depends on many physical mechanisms but can be simplified to a negative balance between restoring forces which try to unstuck the movable mass and the adhesion forces which keep the Read more
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Optimization of systems with Internal Resonances
MEMS design is usually done following linear vibration theory, however, their real behavior often turns out to be nonlinear. To address this issue, our group developed optimization algorithms to target backbone curves, which are striclty connected to the nonlinearity of the vibration modes. As of now, the backbone computation can target only a single mode. Read more
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Topology Optimization in nonlinear dynamics
Topology optimization techniques for the design of MEMS devices in a linear dynamics framework have already been studied in several works in the literature. However, since there is no control of the degree of nonlinearity of the structure during the optimization process, the outcome of these routines often departs significantly from linearity. The consequence is Read more
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Level-set robust topological optimization applied to MEMS accelerometers
MEMS technology is becoming increasingly important for several inertial applications (e.g., gyroscopes and accelerometers devices). The objective of this thesis is to improve the layout of an existing MEMS accelerometer by implementing level-set topology optimization algorithms in existing software written in C++. Robust techniques will be implemented as well in order to minimize the influence Read more
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feMEMS: parametric optimization using semi-lumped parameter models
The design of MEMS devices usually involves several Finite Element (FE) analyses, each with different parameters (e.g. beam thicknesses) to tune the characteristics of the sensor. This trial-and-error procedure is tedious and time-consuming, even more so considering that typical FE models may count 100k-1M degrees of freedom. For this reason, our group developed a Matlab Read more
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ROM for large rotations in a MEMS micromirror
MEMS micromirrors are micro components used to deflect light rays in many applications, such as to build projectors. Mainly due to their large rotations, these devices exhibit a nonlinear behavior that challenges the construction of traditional nonlinear Reduced Order Models. In this thesis, the candidate will investigate the subject of large rotations (moving on from Read more
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Parameter continuation of SSM for parametrized defects
In this project we aim to develop an analytic formulation for Spectral Submanifolds (SSMs) depending on a parameter. In particular, the focus is on a formulation for shape defects previously studied in Marconi et al., where a different MOR strategy was used. Indeed, the problem of shape defects is very important in the MEMS field industry, Read more
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Design of a small-footprint MEMS gyroscope
MEMS gyroscopes are micro sensors for angular rate, which can be found in almost any electric device, from smartphones to drones, cars, and robots. The trend of the industry nowadays is to go for ever smaller footprint sensors so that they can be embedded in a smaller system, absorb less energy, and last (but not Read more