Uncovering the Nonlinear Dynamics of Origami Folding

Origami, the ancient art of paper folding, has found lots of different applications in various branches of science, including engineering. However, most of the studies on engineering applications of origami have been limited to static or quasistatic applications. Origami folding, on the other hand, could be a dynamic process. The intricate nonlinear elastic properties of origami structures can lead to interesting dynamic characteristics and applications. Nevertheless, studying the dynamics of folding is still a nascent field. In this dissertation, we try to expand our knowledge of fundamentals of origami folding dynamics. We look at the problem of origami folding dynamics from two different perspectives: 1) How can we utilize folding-induced mechanical properties for dynamic applications? and 2) How can we fold origami structures using dynamic excitations? In order to answer these questions, we conduct three different projects. Regarding the first perspective, we study a unique asymmetric quasi-zero stiffness (QZS) property from the pressurized fluidic origami cellular structure, and examine the feasibility and efficiency of using this nonlinear property for low-frequency vibration isolation. In another project, we analyze the feasibility of utilizing origami folding techniques to create an optimized jumping mechanism. And finally, regarding the second perspective, we examine a rapid and reversible origami folding method by exploiting a combination of resonance excitation, asymmetric multi-stability, and active control. In addition to these studies, Witnessing the rich and nonlinear dynamic characteristics of origami structures, in this dissertation we introduce the idea of using origami structures as physical reservoir computing systems and investigate their potentials in sensing and signal processing tasks without relying on external digital components and signal processing units

Laser additive manufacturing of Miura-origami tube inspired quasi-zero stiffness metamaterial with prominent longitudinal wave propagation

Origami metamaterials have become frontiers of research in many disciplines due to their infinite design space, simple size variation, and topologically variable properties. In this study, a novel metamaterial inspired by Miura-origami tubes with a complex quasi-zero-stiffness (QZS) structure was fabricated via laser powder bed fusion (LPBF). The unit of the QZS metamaterial consists of a two-layer quadrilateral frame and two vertical springs attached to its diagonal points. The geometric accuracy, densification level and mechanical properties of the QZS parts fabricated at various processing conditions were investigated and the optimised processing parameters were determined. The displacement response of the QZS parts was analysed by experiments in conjunction with simulation analysis. The results show that the LPBF-fabricated QZS metamaterials form four extra-wide longitudinal wave band gaps under low frequencies from 660 Hz to 2500 Hz. The proposed LPBF-fabricated QZS metamaterial shows great potential in impeding the longitudinal vibration of engineering structures

Role of Material Directionality on the Mechanical Response of Miura-Ori Composite Structures

This paper aims to understand the role of directional material properties on the mechanical responses of origami structures. We consider the Miura-Ori structures our target model due to their collapsibility and negative Poisson's ratio (NPR) effects, which are widely used in shock absorbers, disaster shelters, aerospace applications, etc. Traditional Miura-Ori structures are made of isotropic materials (Aluminum, Acrylic), whose mechanical properties like stiffness and NPR are well understood. However, how these responses are affected by directional materials, like Carbon Fiber Reinforced Polymer (CFRP) composites, lacks in-depth understanding. To that end, we study how fiber directions and arrangements in CFRP composites and Miura-Ori's geometric parameters control the stiffness and NPR of such structures. Through finite element analysis, we show that Miura-Ori structures made of CFRP composites can achieve higher stiffness and Poisson's ratio values than those made of an isotropic material like Aluminum. Then through regression analysis, we establish the relationship between different geometric parameters and the corresponding mechanical responses, which is further utilized to discover the Miura-Ori structure's optimal shape. We also show that the shear modulus is a dominant parameter that controls the mechanical responses mentioned above among the individual composite material properties within the Miura-Ori structure. We demonstrate that we can optimize the Miura-Ori structure by finding geometric and material parameters that result in combined stiffest and most compressible structures. We anticipate our research to be a starting point for designing and optimizing more sophisticated origami structures with composite materials incorporated

Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio

Materials and structures with negative Poisson’s ratio exhibit counter-intuitive behaviour, i.e., under uniaxial compression (tension), these materials and structures contract (expand) transversely. The materials and structures that possess this feature are also called ‘auxetics’ by Evans. The terminology of ‘auxetic’ becomes a common adjective to describe materials and structures with negative Poisson’s ratio. Many desirable properties resulting from this unusual behaviour have been reported, e.g., higher shear resistance, indentation resistance, fracture resistance, improved acoustic and higher energy absorption, synclastic behaviour and variable permeability. These superior properties offer auxetics broad potential applications, e.g., smart filters, sensors, medical devices and protective equipment. However, there are still many challenging problems which impede wider applications of auxetics. First of all, most of the studied auxetic materials are two-dimensional (2D) and very few three-dimensional (3D) auxetic materials have been designed and investigated. Secondly, the base materials of the most existing auxetic metamaterials are rubber-like materials, hence these auxetic metamaterials are limited to the elastic deformation. In contrast to elastic auxetic metamaterials, metallic auxetic metamaterials exhibit some new features in mechanical properties, e.g., localisation of plastic strain, strain hardening and irreversible deformation. Furthermore, metallic metamaterials are usually stronger than those made of elastomers, which leads to superior loading resistance and energy absorption. Last but not the least, although most of the publications mention that auxetic materials possess many desirable properties, very few auxetic materials have been designed and fabricated to the practical stage. Therefore, it is worthy of carrying out more original research to explore new applications for auxetic materials. In order to fill the research gap mentioned above and create better auxetic materials for applications, in this study, extensive numerical and experimental investigations have been conducted. Firstly, a novel methodology was proposed to generate a 3D metallic cubic auxetic material based on a cubic buckling-induced auxetic material. It was found that the base material affected the auxetic behaviour of the buckling-induced cubic auxetic materials. When the elastomer base material was replaced with a ductile metallic material, the previously observed auxetic behaviour of the buckling-induced auxetic material would disappear. Inspired by this unexpected behaviour, a new methodology of generating 3D metallic auxetic materials was developed. The effectiveness of the methodology was then proved experimentally and numerically. The mechanical properties of the designed 3D metallic auxetic materials could be easily tuned by one single parameter of pattern scale factor (PSF). In the second part of this study, a simple auxetic tubular structure which exhibited auxetic behaviour both in compression and tension was generated by using the newly proposed PSF methodology. This simple auxetic tubular structure could also be tuned by one single parameter of the PSF. When the scale of PSF reached a certain value (around 60% in this study), the designed tubular structure exhibited an approximately identical auxetic effect both in tension and compression. In the third part of this study, a simple 3D auxetic metamaterial was designed which demonstrated the unexpected 2D auxetic behaviour. By utilising the proposed PSF methodology, the 2D auxetic behaviour could be successfully transformed to 3D auxetic behaviour. Hence, the functionality of the proposed PSF methodology was further extended. In the last part of this study, the first auxetic nails were designed, fabricated and experimentally investigated. According to the experimental results, the designed auxetic nails could not demonstrate superior mechanical performance to non-auxetic nails. Therefore, it would prudent to re-examine the potential applications for auxetic materials because many existing publications in the field might have overestimated the superiorities of auxetic materials and their limitations and disadvantages have been rarely discussed

Using Origami Folding Techniques to Study the Effect of Non-Linear Stiffness on the Performance of Jumping Mechanism

This research uses Origami patterns and folding techniques to generate non-linear force displacement profiles and study their effect on jumping mechanisms. In this case, the jumping mechanism is comprised of two masses connected by a Tachi-Miura Polyhedron (TMP) with non-linear stiffness characteristics under tensile and compressive loads. The strain-softening behavior exhibited by the TMP enables us to optimize the design of the structure for improved jumping performance. I derive the equations of motion of the jumping process for the given mechanism and combine them with the kinematics of the TMP structure to obtain numerical solutions for the optimum design. The results correlate to given geometric configurations for the TMP that result in the two optimum objectives: The maximum time spent in the air and maximum clearance off the ground. I then physically manufacture the design and conduct compression tests to measure the force-displacement response and confirm it with the theoretical approach based on the kinematics. Experimental data from the compression tests show a hysteresis problem where the force-displacement profile exhibits different behavior whether the structure is being compressed or released. I investigate two methods to nullify the hysteresis when compressing or releasing the mechanism and then discuss their results. This research can lead to easily manufacturable jumping robotic mechanisms with improved energy storage and jumping performance. Additionally, I learn more about how to use origami techniques to harness unique stiffness properties and apply them to a variety of scenarios

Technology for large space systems: A bibliography with indexes (supplement 22)

This bibliography lists 1077 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion

Index to NASA tech briefs, 1971

The entries are listed by category, subject, author, originating source, source number/Tech Brief number, and Tech Brief number/source number. There are 528 entries

Cumulative index to NASA Tech Briefs, 1970-1975

Tech briefs of technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Abstracts and indexes of subject, personal author, originating center, and tech brief number for the 1970-1975 tech briefs are presented

Large space structures and systems in the space station era: A bibliography with indexes (supplement 04)

Bibliographies and abstracts are listed for 1211 reports, articles, and other documents introduced into the NASA scientific and technical information system between 1 Jul. and 30 Dec. 1991. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems