Ning Liu | EPFL Graph Search

Ning Liu a obtenu le diplôme de bachelor en conception et ingénierie aéronautique de l'Université Polytechnique du Nord-Ouest, Xi'an, Chine en 2016, et le diplôme d'ingénieur (équivalent du master) en génie mécanique de l'Institut National des Sciences Appliquées (INSA), Lyon, France en 2017, et le diplôme de doctorat en Automatique de l'institut FEMTO-ST (UMR CNRS 6174), Université Bourgogne Franche-Comté, Besançon, France, en 2020.Depuis 2021, elle est chercheuse postdoctorale au Laboratoire des actionneurs intégrés, École polytechnique fédérale de Lausanne (EPFL), Neuchâtel, Suisse.Ses intérêts de recherche incluent les actionneurs à base de polymère électro-actif, les systèmes Hamiltoniens à ports, les méthodes de discrétisation préservant la structure et les commandes basées sur la passivité.

Control-oriented modeling and analysis of tubular dielectric elastomer actuators dedicated to cardiac assist devices

Yoan René Cyrille Civet, Ning Liu, Thomas Guillaume Martinez, Yves Perriard, Armando Matthieu Walter

This paper deals with the control-oriented modeling of a multilayered dielectric elastomer actuator based tube. The actuator is clamped at both sides and performs a radial displacement. The hyperelastic deformation and the viscoelastic performance, together with the electro-mechanical coupling are considered in the model. With the chosen Yeoh’s model for the Helmholtz free energy function, we aim to model the snapthrough effect of this tubular actuator at high applied voltage. Simulation results of the nonlinear dynamic model are later compared with experimental ones in order to identify unknown parameters of the dielectric elastomer, especially to fit the snapthrough effect and the high frequency performance. With proper identification process, our model has a good accuracy to fit the physical system (more than 90.27% for a ramp input and more than 82.7% for a step input) and is ready for the future controller design.

2022

Sustainable Architecture for Educational Space in Africa and China

Ning Liu

Countries in the Global South are producing the most important educational needs of the 21st century. Fast-growing cities can provide the most striking examples of these current tendencies. Just over a decade after the start of the new millennium, the needs for quality-education and appropriate learning space are huge. Yet they are still largely underestimated in many countries of the Global South. With high-level demographical growth and fast-expanding urban boundaries, the developing metropolis provides a fascinating place to analyze societal mutations. School â as one of the fundamental institutions in modern society â deserves timely observation and careful analysis. The research work is dedicated to the study of educational architecture in two African cities Ouagadougou (Burkina Faso) and Cape Town (South Africa) and one Chinese city: Hangzhou. Because of the fundamental relationship between school and society, learning places need to make statement of their urban positions. The hypothesis proposes to question the concept of sustainability in the framework of cultural-environmental qualities between school and city, between users and space. Conducted by an architect, this thesis is the synthesis of a research process together with the professional practice. It is benchmarked by a path of three steps: critical analysis of literature, in situ case-study and cross-cultural comparison with proposal of an assessment method that opens up for future perspectives. The thesis argues that the current time is crucial for our society to reconsider the place of educational architecture in the city. A truly sustainable architecture is transformable in the time-span of its usage and transformative in the changing urban environment. With a discursive comparative view between built cases located in these three cities, this work attempts to provide new insights on the design of the learning space in the urban future. The synthesis provides a panel of cultural-environmental quality profiles as guidelines to future design innovation opportunities.

EPFL2015

Sustainable Architecture for Educational Space in Africa and China

Ning Liu

EPFL2015