THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201707035

Soft Robotic Grippers.

Structural systems often show nonlinear behavior under severe excitations generated by natural hazards. In that condition, the restoring force becomes highly nonlinear showing significant hysteresis. The hereditary nature of this nonlinear restoring force indicates that the force cannot be described as a function of the instantaneous displacement and velocity. Accordingly, many hysteretic restoring force models were developed to include the time dependent nature using a set of differential equations. This survey contains a review of the past, recent developments and implementations of the Bouc-Wen model which is used extensively in modeling the hysteresis phenomenon in the dynamically excited nonlinear structures.

The Hysteresis Bouc-Wen Model, a Survey

Topology optimization has become an effective tool for least-weight and performance design, especially in aeronautics and aerospace engineering. The purpose of this paper is to survey recent advances of topology optimization techniques applied in aircraft and aerospace structures design. This paper firstly reviews several existing applications: (1) standard material layout design for airframe structures, (2) layout design of stiffener ribs for aircraft panels, (3) multi-component layout design for aerospace structural systems, (4) multi-fasteners design for assembled aircraft structures. Secondly, potential applications of topology optimization in dynamic responses design, shape preserving design, smart structures design, structural features design and additive manufacturing are introduced to provide a forward-looking perspective.

Topology Optimization in Aircraft and Aerospace Structures Design

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review.

The magnetorheological elastomers (MREs) are novel multifunctional materials which their viscoelastic properties can be varied instantly under an application of applied magnetic field. Due to their field-dependent stiffness and damping properties, MREs have been widely used in the development and design of MRE-based adaptive vibration isolators and absorbers and also biomedical engineering. Moreover, MREs due to their inherent magnetostriction effect have enormous potential for the development of soft actuators. The dynamic behavior of MREs is affected by various material parameters (ex., matrix and particle types, particle concentration, additives) as well as mechanical and magnetic loading parameters (ex. frequency, amplitude, temperature, magnetic flux density). Understanding and predicting the effect of materials and loading parameters on the response behavior of MREs are of paramount importance for the design of MRE-based adaptive structures and systems. This review paper mainly aims to provide a comprehensive study of material constitutive models to predict the nonlinear magneto-mechanical behavior of MREs. Particular emphasis will be paid to physics-based models including continuum- and microstructure-based models. Moreover, phenomenological models describing the dynamic magneto-viscoelastic behavior of MREs as well as the effect of temperature on the magneto-mechanical behavior of such materials have been properly addressed. This article is protected by copyright. All rights reserved. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/adem.202300182

On the Modeling of Magnetorheological Elastomers: A State‐of‐the‐art Review

In this study, a finite element model has been developed to analyze the nonlinear response characteristics of a magnetoactive soft robotic cantilever beam under varied external magnetic field. The validity of the model is demonstrated by comparing the simulation results with the available experimental data. The deflection of the soft robotic beam increased linearly with the magnetic field under low magnetic flux density and approached saturation under a higher magnetic field. Owing to the highly nonlinear response of the robot, an optimal Fuzzy-PID controller is designed to make the magnetic soft robot track the predefined path. Simulation results show superior tracking performance of the proposed optimal Fuzzy-PID controller when compared to the optimal PID control method. 

Nonlinear Dynamic Analysis and Control of a Small-Scale Magnetoactive Soft Robot

Semi-Active Sound Transmission Control of Sandwich Panels Treated with MR Fluid Core Layer

Three-dimensional finite element (FE) models of a honeycomb non-pneumatic wheel (NPW) with three different spokes configurations of varying cell angles were developed in ABAQUS software in order to investigate its modal properties under a given normal load. The validity of these wheel models was confirmed through comparisons of predicted wheel responses with available data in published studies for similar wheel material properties and components dimensions. The important vibration modes affecting the wheel responses were initially identified together with the important design factors affecting the modal properties. Response surface models relating the natural frequency of each chosen influential vibration mode with its important design factors and the two-factor interactions were subsequently developed utilizing the results of FE simulations corresponding to design points of the screening design and the experimental design based on central composite design (CCD) approach. These regression models showed good fitting accuracy of the natural frequencies obtained in CCDs together with relatively satisfactory prediction ability over the design region considered. The resulting regression models are thus considered to serve as a design guidance for realizing desired wheel modal properties. The results derived from parametric studies showed that natural frequencies of identified in-plane and out-of-plane vibration modes are significantly affected by design parameters of the spokes. These include the initial elastic modulus and thickness of the honeycomb cell-wall and the cell angle. Most of the identified vibration modes are also strongly influenced by the thickness dimensions of the core layer and the tread, while their initial elastic moduli revealed considerable effects only on the wheel Hop and Twist modes. 

Modal properties of honeycomb wheels: A parametric analysis using response surface method

The Distributed Tuned Mass Damper (DTMD) technology, which is one of the modifications of the classical Tuned Mass Damper (TMD) technique, is defined as the multiple TMD design based on one mode of the primary structures. The modeling procedure for this kind of problem is similar to that for the single TMD design, especially for discrete (or modeled as) primary structures, such as the building-type structures. Therefore, the challenge work in this area is to attain the best vibration suppression performance through an optimally designed DTMD system. From the point of optimization, basically, two typical approaches have been utilized to design the DTMD system. The first one is to directly obtain the transfer function and then define the variance or the Dynamic Magnification Factors (DMF) as objective functions, which was utilized by many researchers. In the other methodology, the transfer function is expressed as a dynamic model with an optimal H2 controller under predefined form. In this study, a new optimal DTMD design approach will be presented, in which the optimization objective function and method will be established based on the Linear Quadratic Controller design method. The presented method provides a simple and straightforward way to design the DTMD system. The numerical example will be presented to illustrate the vibration suppression performance of the optimally designed DTMD system.Copyright © 2010 by ASME

Ramin Sedaghati

Papers

On the Modeling of Magnetorheological Elastomers: A State‐of‐the‐art Review

Nonlinear Dynamic Analysis and Control of a Small-Scale Magnetoactive Soft Robot

Semi-Active Sound Transmission Control of Sandwich Panels Treated with MR Fluid Core Layer

Modal properties of honeycomb wheels: A parametric analysis using response surface method

Vibration Suppression Using Distributed Tuned Mass Damper Technology