Vibration Damping of Carbon Nanotube Assembly Materials

Vibration reduction is of great importance in various engineering applications, and a material that exhibits good vibration damping along with high strength and modulus has become more and more vital. Owing to the superior mechanical property of carbon nanotube (CNT), new types of vibration damping material can be developed. This paper presents recent advancements, including our progresses, in the development of high-damping macroscopic CNT assembly materials, such as forests, gels, films, and fibers. In these assemblies, structural deformation of CNTs, zipping and unzipping at CNT connection nodes, strengthening and welding of the nodes, and sliding between CNTs or CNT bundles are playing important roles in determining the viscoelasticity, and elasticity as well. Towards the damping enhancement, strategies for micro-structure and interface design are also discussed

Made-by-hand: [re]valuing traditional (Japanese) textile practices for contemporary design

Textiles touch all our lives – from the cradle to the grave – and serve increasingly diverse purposes. Historically, and as one of the first industrialized commodities, the skill and knowledge required to construct fabrics to clothe and furnish has dominated cultures worldwide. Contemporary Japanese textile design draws on countless traditions of often ancient but sustained craft practices. These traditions both respond to and employ the natural condition of things, exercising heightened and honed sensibilities to material know-how. Discussed through the discipline of woven textiles and, in particular, ‘traditional’ Japanese production systems, this article seeks to identify the location and distribution of both practical and aesthetic expertise in textile making and its transferable value for contemporary practices. The article presents case studies of surviving vernacular ‘cottage’ industries, where highly organized systems of knowledge exchange, spanning agricultural fibre production to direct technical instruction in thread making, ensure effective engagement with and ‘management’ of very specific materiality. The notion of intangible cultural property will be discussed in the context of inherited knowledge and how traditional social hierarchies and knowledge systems have served to nurture and perpetuate the sharing of skills and understanding through generations of textile makers and making

Smart Textiles in Building and Living Applications: WG4 CONTEXT Insight on Elderly and Healthcare Environments

Over the past 30 years, the development of new technologies and especially of smart textiles has unavoidably led to new applications of traditional textiles in the built environment. Depending on special constructional needs (i.e., acoustic insulation, thermal insulation, shading system, etc.) or health monitoring and supporting needs (i.e., for patients with chronical disease, etc.), an increasing number of possible applications has been proposed to improve human well-being. This is especially the case for healthcare environments (like elderly or nursing homes, etc.), but also educational environments (like schools, etc.) where young or old customers can benefit from technological innovation in several ways. As an ongoing activity of WG4 members for the CA17107 “CONTEXT” European research network, this study presents a review on selected applications for building and living solutions, with special attention to healthcare environments, giving evidence of major outcomes and potentials for smart textiles-based products

A Wearable Heating System with a Controllable e-Textile- Based Thermal Panel

Flexible textile heating systems present great advantage due to their ability to bend and hence could ensure uniform heating for irregular geometries. In cooler outer environment, the user requires his/her body to be kept warm for monitoring vital body functions within realistic thermal body balance constraints. In this chapter, heated vest with controllable e-textile-based thermal panel has been studied. Several e-textile-based thermal panels with different conductive yarns were produced using hot air welding technology under different manufacturing parameters. E-textile-based thermal panels were tested for their heating behaviors at varying direct current (DC) power levels. Based on the experimental results, the optimum e-textile-based thermal panel design was chosen considering its flexibility and uniform heating behavior. Moreover, a control algorithm with electrical circuit and electrical connection network was designed and assembled in an electronic control module. Finally, the electronic module consisting of power control and management system was integrated to attachable e-textile-based thermal panel in order to form a wearable heating vest

Multi-Scale Models to Simulate Interactions between Liquid and Thin Structures

In this dissertation, we introduce a framework for simulating the dynamics between liquid and thin structures, including the effects of buoyancy, drag, capillary cohesion, dripping, and diffusion. After introducing related works, Part I begins with a discussion on the interactions between Newtonian fluid and fabrics. In this discussion, we treat both the fluid and the fabrics as continuum media; thus, the physical model is built from mixture theory. In Part II, we discuss the interactions between Newtonian fluid and hairs. To have more detailed dynamics, we no longer treat the hairs as continuum media. Instead, we treat them as discrete Kirchhoff rods. To deal with the thin layer of liquid that clings to the hairs, we augment each hair strand with a height field representation, through which we introduce a new reduced-dimensional flow model to solve the motion of liquid along the longitudinal direction of each hair. In addition, we develop a faithful model for the hairs' cohesion induced by surface tension, where a penalty force is applied to simulate the collision and cohesion between hairs. To enable the discrete strands interact with continuum-based, shear-dependent liquid, in Part III, we develop models that account for the volume change of the liquid as it passes through strands and the momentum exchange between the strands and the liquid. Accordingly, we extend the reduced-dimensional flow model to simulate liquid with elastoviscoplastic behavior. Furthermore, we use a constraint-based model to replace the penalty-force model to handle contact, which enables an accurate simulation of the frictional and adhesive effects between wet strands. We also present a principled method to preserve the total momentum of a strand and its surface flow, as well as an analytic plastic flow approach for Herschel-Bulkley fluid that enables stable semi-implicit integration at larger time steps. We demonstrate a wide range of effects, including the challenging animation scenarios involving splashing, wringing, and colliding of wet clothes, as well as flipping of hair, animals shaking, spinning roller brushes from car washes being dunked in water, and intricate hair coalescence effects. For complex liquids, we explore a series of challenging scenarios, including strands interacting with oil paint, mud, cream, melted chocolate, and pasta sauce

Spacesuit Integrated Carbon Nanotube Dust Mitigation System For Lunar Exploration

Lunar dust proved to be troublesome during the Apollo missions. The lunar dust comprises of fine particles, with electric charges imparted by solar winds and ultraviolet radiation. As such, it adheres readily, and easily penetrates through smallest crevices into mechanisms. During Apollo missions, the powdery dust substantially degraded the performance of spacesuits by abrading suit fabric and clogging seals. Dust also degraded other critical equipment such as rovers, thermal control and optical surfaces, solar arrays, and was thus shown to be a major issue for surface operations. Even inside the lunar module, Apollo astronauts were exposed to this dust when they removed their dust coated spacesuits. This historical evidence from the Apollo missions has compelled NASA to identify dust mitigation as a critical path. This important environmental challenge must be overcome prior to sending humans back to the lunar surface and potentially to other surfaces such as Mars and asteroids with dusty environments. Several concepts were successfully investigated by the international research community for preventing deposition of lunar dust on rigid surfaces (ex: solar cells, thermal radiators). However, applying these technologies for flexible surfaces and specifically to spacesuits has remained an open challenge, due to the complexity of the suit design, geometry, and dynamics. The research presented in this dissertation brings original contribution through the development and demonstration of the SPacesuit Integrated Carbon nanotube Dust Ejection/Removal (SPIcDER) system to protect spacesuits and other flexible surfaces from lunar dust. SPIcDER leverages the Electrodynamic Dust Shield (EDS) concept developed at NASA for use on solar cells. For the SPIcDER research, the EDS concept is customized for application on spacesuits and flexible surfaces utilizing novel materials and specialized design techniques. Furthermore, the performance of the active SPIcDER system is enhanced by integrating a passive technique based on Work Function Matching coating. SPIcDER aims for a self-cleaning spacesuit that can repel lunar dust. The SPIcDER research encompassed numerous demonstrations on coupons made of spacesuit outerlayer fabric, to validate the feasibility of the concept, and provide evidence that the SPIcDER system is capable of repelling over 85% of lunar dust simulant comprising of particles in the range of 10 m-75m, in ambient and vacuum conditions. Furthermore, the research presented in this dissertation proves the scalability of the SPIcDER technology on a full scale functional prototype of a spacesuit knee joint-section, and demonstrates its scaled functionality and performance using lunar dust simulant. It also comprises detailed numerical simulation and parametric analysis in ANSYS Maxwell and MATLAB for optimizing the integration of the SPIcDER system into the spacesuit outerlayer. The research concludes with analysis and experimental results on design, manufacturability, operational performance, practicality of application and astronaut safety. The research aims primarily towards spacesuit dust contamination. The SPIcDER technology developed in this research is however versatile, that can be optimized to a wide range of flexible surfaces for space and terrain applications-such as exploration missions to asteroids, Mars and dust-prone applications on Earth