Publications related to Stiffness

Filiform Variable Stiffness Technologies for Medical Robotics

In recent years, soft robotics has surged in applications like wearables, drones, smart fabrics, and medical instruments. Due to their compliance, these devices excel in tasks demanding dexterity and adaptability, such as manipulation, locomotion, crash re ...

EPFL2024

Energy dissipation in fiber-polymer composites adhesive joints under cyclic loading

Ghazaleh Eslami

Sustainable development has emerged as a paramount consideration in various fields of industry, including construction, to preserve the environment and its finite resources. Lightweight structures, such as fiber-polymer composite structures, address both s ...

EPFL2023

Shear strength and shear stiffness analysis of compacted Wyoming-type bentonite

Alessio Ferrari

Wyoming-type bentonite is one of the materials to be used as part of the Engineered Barrier System (EBS) in deep geological disposal facilities for the safe disposal of spent nuclear fuel.In the KBS-3 type repository, the canisters containing the spent fue ...

ELSEVIER2023

Auto-tuning deep forest for shear stiffness prediction of headed stud connectors

Xianlin Wang, Yuqing Liu

The shear stiffness of headed stud connector is a critical parameter for the calculation of deflection and inter-facial shear force for steel-concrete composite structure. Thus, this study presented a promising data-driven model auto-tuning Deep Forest (AT ...

2022

Deformation and Fracture of Tough Microstructured Hydrogels

Michael David Kessler

Many natural materials are structured on different length scales. This structuring often leads to an intricate interplay between soft and stiff components, which significantly improves the fracture toughness of these materials. A class of soft material tha ...

EPFL2022

Electro-Adhesive Tubular Clutch for Variable-Stiffness Robots

Dario Floreano, Yi Sun, Hoang Vu Phan, Krishna Manaswi Digumarti, Omar Aloui

Electro-adhesive clutches have become effective tools for variable stiffness functions in many robotic systems due to their light weight, high speed and strong brake force. In this paper, we present a novel, tubular design of an electro-adhesive clutch. Ou ...

IEEE2022

Load cell with positive, negative and zero stiffness operating modes for milli- to nanonewton contact force monitoring in electrical probing

Michal Stanislaw Smreczak

Monolithic integrated circuits (ICs) have been miniaturized over the past five decades, and today their components range in size from hundreds of microns to several nanometers. Making point contact with electrical samples under a microscope is referred to ...

EPFL2022

Triple Crossed Flexure Pivot Based on a Zero Parasitic Center Shift Kinematic Design

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann

Thanks to their absence of play, absence of contact friction and possible monolithic fabrication, flexure pivots offer advantages over traditional bearings in small-scale, high accuracy applications and environments where lubrication and wear debris are pr ...

2022

A Variable Stiffness Magnetic Catheter Made of a Conductive Phase-Change Polymer for Minimally Invasive Surgery

Dario Floreano, Yegor Piskarev, Jun Shintake

Variable stiffness (VS) is an important feature that significantly enhances the dexterity of magnetic catheters used in minimally invasive surgeries. Existing magnetic catheters with VS consist of sensors, heaters, and tubular structures filled with low me ...

2022

Manufacturing and toughening effects on the material properties of wind turbine blade adhesives

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

Hybrid adhesives can be developed using commercially available adhesive materials and customized to the required loading conditions. In this paper, SPABONDTM 820HTA (non-toughened) and SPABONDTM 840HTA (toughened) adhesives are hybridized by two strategies ...

2022

Active load cell with positive, negative and zero stiffness operating modes for micronewton range contact force monitoring in electrical probing

Simon Nessim Henein, Charles Baur, Hubert Pierre-Marie Benoît Schneegans, Michal Stanislaw Smreczak

This article describes a novel method for applying a contact force in the range of 1 to 100 μN with pointed probe on a microscale sample in order to perform ohmic electrical measurements. The solution is based on the new TIVOT active load cell combining th ...

2022

A numerical approach to characterize the viscoelastic behaviour of fibre beds and to evaluate the influence of strain deviations on viscoelastic parameter extraction

Véronique Michaud, Vincent Werlen, Christian Rytka

The development of a robust material model able to accurately describe fibre bed compaction at different strain and strain rates is highly desirable because it is essential for the simulation of many composite manufacturing processes. In this study, we inv ...

2021

Shear Response of Wet Weak Carbonate Rock/Grout Interfaces Under Cyclic Loading

Eleni Stavropoulou

The development and construction of offshore wind farms requires the correct estimation of the friction that can be mobilised at the rock/grout interface. In conventional studies, the shear behaviour of a joint is usually investigated with laboratory tests ...

2021

RC U-shaped walls subjected to in-plane, diagonal, and torsional loading: New experimental findings

Katrin Beyer, Ryan Hoult

Although reinforced concrete U-shaped walls are popular in construction practice internationally, there is a paucity of experimental research investigating the seismic performance of such salient elements. The present paper summarizes an experimental campa ...

2021

Numerical modeling of two-dimensional delamination growth in composite laminates with in-plane isotropy

Thomas Keller, Anastasios Vassilopoulos, Congzhe Wang

The two-dimensional (2D) delamination growth in fiber-reinforced polymer (FRP) laminates with in-plane isotropy under Mode I loading condition was numerically investigated using finite element analyses. Two sizes of plate models were developed, focusing on ...

2021

Decay of Torsional Stiffness in RC U-Shaped Walls

Katrin Beyer, Ryan Hoult

Reinforced concrete (RC) U-shaped walls are a popular construction choice, commonly used to resist the lateral loads from wind and earthquakes. In many buildings, the center of stiffness of a floor is eccentric from the center of mass and the building will ...

2020

Microstructural simulation and measurement of elastic modulus evolution of hydrating cement pastes

Karen Scrivener, Cyrille Dunant, Arnaud Charles Albert Muller, Arnaud Müller

Predicting the evolution of stiffness in cement paste requires linking morphological properties of the microstructure to the evolution of mechanical properties. Measures are typically difficult to obtain with sufficient time resolution to capture the trans ...

Pergamon-Elsevier Science Ltd2020

Poly(lactide)/cellulose nanocrystal nanocomposites by high-shear mixing

Véronique Michaud, Nicolas Candau, Oguzhan Oguz, Adrien Julien Demongeot, Mehmet Kerem Citak, Fatma Nalan Cetin

There is currently considerable interest in developing stiff, strong, tough, and heat resistant poly(lactide) (PLA) based materials with improved melt elasticity in response to the increasing demand for sustainable plastics. However, simultaneous optimizat ...

WILEY2021

Tuning stiffness nonlinearty: theory and applications

Simon Nessim Henein, Ilan Vardi, Mohamed Gamal Abdelrahman Ahmed Zanaty

Perfect elasticity is not achievable in real-life situation, so spring stiffness is not perfectly constant. In this paper, we study the effect of modifying non-linear stiffness terms while keeping the nominal stiffness constant. We introduce three methods ...

ASME2020

Concurrent multiscale modeling and theory of solute-strengthening for dilute and complex concentrated alloys

Shankha Nag

Under common processing conditions, both dilute and complex concentrated alloys are often realized as random alloys, with no correlation in the occupancy of lattice sites by the constituent atom types. The current thesis primary addresses two problems in r ...

EPFL2020