Optical Waveguide Theory

생체의 모델링과 Simulation

A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.

https://iopscience.iop.org/article/10.1088/0964-1726/24/6/063001/pdf

Buckling-induced smart applications: recent advances and trends

Nonlinear finite element analysis of solids and structures by M.A. Crisfield

A review of topology optimization for additive manufacturing: Status and challenges

Variable compliance mechanisms are considered as an effective way for interaction with changeable environments. Existing designs of variable compliance mechanisms can only change the amplitude of compliance rather than the orientation of compliance. In this paper, a novel hybrid mechanism is designed to realize changeable compliance orientation in a large range. The mechanical structure and working principle of the designed mechanism are firstly presented. Then, the closed-form relationship between compliance orientation and configuration of the designed mechanism is analyzed. Spherical coordinates are used to characterize and evaluate the orientation of compliance. Theoretical analysis shows that the orientation of compliance can be changed in a large range spatially. Finite element analysis is also performed to verify the theoretical model. It shows that the orientations of deformation during simulations are close to the theoretical compliance orientations. Under unchanged loading conditions, a large change in deformation orientation can be achieved by changing the mechanism’s configuration. This indicates that the designed mechanism can change the compliance orientation in a large range.

Design of a Variable Compliance Mechanism with Changeable Compliance Orientation

The invention discloses a planar complex structural space and large stroke type lamina emergent torsional joint. The planar complex structural space and large stroke type lamina emergent torsional joint comprises a rectangular plane unit for realizing out-of-plane twisting function, and a fork-shaped plane unit for realizing in-plane rotating function, wherein the fork-shaped plane unit is of a fork-shaped structure which is formed by intersecting two flexible straight-beam thin sheets, and the fork-shaped structure is provided with an included angle; and the rectangular plane unit and the fork-shaped plane unit are connected in an outer linking manner or an embedding manner. The planer complex structural space and large stroke type lamina emergent torsional joint overcomes problems of anexisting planar structural lamina emergent torsional joint, such as that the existing planar structural lamina emergent torsional joint is equivalent to a single-degree-of-freedom large stroke low movement pair, an LEMs (Lamina Emergent Mechanisms) are equivalent to a multi-degree-of-freedom lamina emergent torsional joint, and the overall stroke is small

Planar complex structural space and large stroke type lamina emergent torsional joint

The invention discloses a multi-steady-state compliant Bricard mechanism and a steady-state analysis method thereof. The multi-steady-state compliant Bricard mechanism is formed by connecting a plurality of Bricard basic units in an end-to-end manner so as to form an annular closed structure; each Bricard basic unit comprises two flexible hinges and two rigid connecting parts, which the two flexible hinges are provided with different planes orthogonal to each other, and two rigid connecting parts are used for enabling the flexible hinges to be connected; every two flexible hinges are connectedthrough one rigid connecting part; one flexible hinge is connected to one flexible hinge of the adjacent Bricard basic unit through the other rigid connecting part; the two rigid connecting parts inthe same Bricard basic unit have to be equal in length; but the rigid connecting parts of different Bricard basic units do not have to be equal in length. The multi-steady-state compliant Bricard mechanism and the steady-state analysis method thereof have the advantages that the continuous rotation, multiple steady states and the like of a compliant triple Bricard mechanism can be achieved, meanwhile, the mechanism topology is changeable, the unit number is adjustable, and implementation and popularization are easy.

Multi-steady-state compliant Bricard mechanism and steady-state analysis method thereof

The development of automation at the nanoscale has been calling for precision motion sensing for robotic nanopositioners. This study presents a microvision-based measurement system for the accurate and efficient motion sensing of three-degree-of-freedom (DOF) nanopositioners. In this measurement system, an optimized target searching (OTS) scheme is proposed for automatic tracking target selection. A strategy is designed to combine feature matching with phase correlation to balance the measurement accuracy and efficiency. By proposing a multiple target tracking scheme, high-precision angular measurement is achieved, and velocity estimation is also provided in this microvision-based measurement system. Subsequently, offline simulations and online experiments are performed to comprehensively evaluate the performances of the microvision-based system with comparisons to traditional instrumentation. The simulation and experimental results demonstrate that the proposed system and marker-free method can realize excellent extensibility, strong robustness, and high precision of motion tracking for the nanopositioners, with measurement accuracy higher than 93 nm and 96 $\mu $ rad.

A Microvision-Based Motion Measurement System for Nanopositioners Using the Feature-to-Phase Method

A compliant joint that has a large stroke in a planar composite structure space, comprising a rectangular planar unit (1) used for implementing an out-of-plane torsion function and a fork-shaped planar unit (2) used for implementing an in-plane rotation function, wherein the fork-shaped planar unit (2) is a fork-like structure that has an included angle into which two flexible straight beam sheets (201) intersect, and the rectangular planar unit (1) and the fork-shaped planar unit (2) are connected in an external or embedded manner. The present joint overcomes the problems in which existing planar structure compliant joints may only be equivalent to a single-degree-of-freedom large-stroke low-motion pair and existing LEMs compliant mechanisms are equivalent to multi-degree-of-freedom compliant joints that have smaller overall strokes, and has the advantages of a simple structure, easy processing, easy analysis and calculation, equivalent large stroke space and multiple degrees of freedom flexibility, and so on.

Benliang Zhu

Papers

Design of a Variable Compliance Mechanism with Changeable Compliance Orientation

Planar complex structural space and large stroke type lamina emergent torsional joint

Multi-steady-state compliant Bricard mechanism and steady-state analysis method thereof

A Microvision-Based Motion Measurement System for Nanopositioners Using the Feature-to-Phase Method

Compliant joint having large stroke in planar composite structure space