Norman M. Wereley

University of Maryland, College Park | UMD, UMCP, University of Maryland College Park · Department of Aerospace Engineering

This study examines the three-axis vibration isolation capabilities of a full-scale magnetorheological (MR) seat suspension system utilizing experimental methods to assess performance under both single-axis and simultaneous three-axis input conditions. To achieve this, a semi-active MR seat damper was designed and manufactured to address excitation...

Soft continuum robots, characterized by their dexterous and compliant nature, often face limitations due to buckling under small loads. This study explores the enhancement of axial performance in soft robots intrinsically actuated with extensile fluidic artificial muscles (EFAMs) through the incorporation of bio-inspired radial supports, or ossicle...

Honeycomb (HC) has been used in energy absorption applications due to its high stiffness and low density. Metallic HC are used for energy absorption applications, however, these metallic structures can be challenging to manufacture if complex geometric features designed to improve energy absorption are used, which motivates the use of additive manu...

This study focuses on the development and compressive characteristics of magnetorheological elastomeric foam (MREF) as an adaptive cushioning material designed to protect payloads from a broader spectrum of impact loads. The MREF exhibits softness and flexibility under light compressive loads and low strains, yet it becomes rigid in response to hig...

This article examines amorphous glass-based foams as lightweight core materials for crash-resistant structures that offer tailorable energy absorption capabilities. Hollow glass microspheres (HGMs) of different densities are layered using dry powder print- ing (DPP), an additive manufacturing process, and subsequently sintered to consolidate these...

Find the OA paper in the journal of SMS webpage as below: https://iopscience.iop.org/article/10.1088/1361-665X/ad278b Since last two decades, magnetorheological (MR) fluids have attracted attention extensively since they can rapidly and continuously control their rheological characteristics by adjusting an external magnetic field. Because of this...

The sedimentation evaluation of magnetorheological fluids (MRFs) is a key component to developing successful commercial MRF-based engineering applications. In this study, the long-term sedimentation stability of highly stable high-viscosity linear polysiloxane-based MRFs (HVLP MRFs) was experimentally investigated by using an automated vertical axi...

In this study, an electromagnetic energy harvester for a low-frequency ocean wave was developed in a compact 3D-printed structure. Ocean wave energy conversion technologies exist, but maintaining them in the harsh marine environment is crucial for business. Friction increases maintenance costs. Therefore, magnetic levitation, being friction-free, i...

The increasing demand for the adept handling of a diverse range of objects in various grasp scenarios has spurred the development of more efficient and adaptable robotic claws. This study specifically focuses on the creation of an adaptive magnetorheological fluid (MRF)-based robotic claw, driven by electro-permanent magnet (EPM) arrays to enhance...

This study addresses the holding performance of an adaptive magnetorheological fluid (MRF)-based robotic claw that can grasp a wide range of objects satisfying various grasping task requirements. To this end, a two-finger type of MRF-based robotic claw was proposed in this study. Two magnetorheological (MR) grippers with MR elastomer (MRE) bladders...

In this study, magnetorheological fluids (MRFs) were encapsulated in a compact 3D-printed fluid damper, and the field-dependent mechanical properties, such as stiffness and damping, of the MRF damper were experimentally evaluated. To this end, an MRF prepared with a 40% volume fraction of iron particles and silicone oil was injected into the 3D-pri...

Energy-absorbing materials have extensive applications in aerospace and automotive applications. Research has shown buckling initiators, or triggers, in energy-absorbing tubular structures increase the energy absorbed by encouraging the side panels to fold when loaded out of plane in compression conditions. Additively manufactured TPE honeycombs we...

Magnetically responsive soft matter is a colloidal model system where interparticle interactions can be tuned through external magnetic fields. Covering the most recent literature in the field, with special emphasis on the physical mechanisms behind their rheological behaviour, this book aims to demonstrate the controllability of soft matter throug...

We investigate the feasibility of a sliding seat with a magnetorheological (MR) energy absorber (MREA) to minimize loads transmitted to a payload in a ground vehicle for frontal impact speeds ranging as high as 7 m/s (15.7 mph). The crash pulse for a given impact speed was assumed to be a rectangular deceleration pulse having a prescribed magnitude...

Stable magnetorheological fluids (MRFs) are inevitably required to develop reliable MRF-based applications. Suspension stability of MRFs can be studied using an automated vertical axis inductance monitoring system (AVAIMS), where an inductance sensor is translated vertically along a column of MRF to measure particle concentration as a function of c...

In this study, a magnetorheological fluid (MRF) was encapsulated in a 3D printed cellular elastomeric encapsulant. Mechanical properties, such as stiffness and damping, of the encapsulant containing MRFs can be controlled via applied magnetic field. Such tunability can be exploited for adaptive vibration control or energy absorption systems. Here,...

The research in this paper entails the design of material systems with tunable energy-absorbing properties. Hollow glass microspheres of different densities are layered using dry powder printing and subsequently sintered to form a cellular structure. The tunability of the bilayer foams is investigated using various combinations of hollow microspher...

The yield stress of magnetorheological (MR) fluids has been shown to depend on particle morphology, but the exact nature of this contribution is still not fully understood. In this study, MR fluids containing 4 vol. % cobalt particles (spherical particles vs. nanowires) suspended in silicone oil were investigated. The influence of the aspect ratio...

Pneumatic artificial muscles (PAMs) are becoming an increasingly popular form of soft actuator due to their unique actuation characteristics. The creation of accurate PAM actuation models is important for their successful implementation. However, PAM studies often employ actuation models that use simplifying assumptions which make the models easier...

This study evaluates the vibration isolation performance of an adaptive magnetorheological elastomer (MRE)-based dynamic vibration absorber (MRE-DVA) for mitigating the high frequency vibrations (100–250 Hz) of target devices. A simple and effective MRE-DVA design was presented and its vibration isolation performance was experimentally measured. A...

Low stiffness, large stroke, and axial force capabilities make Extensile Fluidic Artificial Muscles (EFAMs) a feasible soft actuator for continuum soft robots. EFAMs can be used to construct soft actuated structures that feature large deformation and enable soft robots to access large effective workspaces. Although FAM axial properties have been we...

In this study, a simple but effective design of an adaptively tunable magnetorheological elastomer (MRE)-based seat vibration absorber (SVA) is presented to achieve better vibration reduction of a propeller aircraft seat. In order to effectively concentrate the magnetic field generated from the electromagnet into the MRE pad areas, an electromagnet...

Pneumatic artificial muscles (PAMs) are simple mechanical actuators that consist of an elastomeric bladder within a braided mesh sleeve. Upon pressurization of the bladder, the actuator may either contract or extend axially, with the direction of motion dependent on the orientation of the braided sleeve fibers. PAMs that have been constructed for c...

In this study, magnetorheological fluid (MRF) was successfully encapsulated in a 3D printed elastomeric cellular structure. To this end, an MRF, which was composed of (40% volume fraction) carbonyl iron particles (6 – 10 μm in diameter) suspended in silicone oil, was encapsulated in a thermoplastic polyurethane (TPU) elastomeric cellular structure....

Magnetorheological (MR) fluids are composed of magnetizeable particles suspended in a carrier fluid and change apparent viscosity upon the application of a magnetic field. Previous studies have shown that passive particles, such as hollow glass spheres, can augment the yield stress of MR fluids, but this yield stress augmentation has limited endura...

This study addresses the synthesis and field-dependent rheological characteristics of novel magnetorheological fluids (MRFs) using high viscosity linear polysiloxanes (HVLPs) as a carrier fluid. First of all, the components and preparation of novel HVLP-based MRFs (HVLP MRFs) were explained in detail and the microscopic images of each component wer...

This study experimentally investigated the different designs of magnetorheological fluid elastomeric encapsulations (MREEs) in order to improve their controllable mechanical properties range. To this end, four different MREE design samples were fabricated, and their stress-strain tests were conducted at constant strain rate conditions by using mate...

Development of magnetorheological elastomer (MRE) materials suitable for fused filament fabrication (FFF)-type additive manufacturing processes is performed. Filament materials are thermoplastic polyurethane (TPU) pellets and Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="...

The research in this article entails the design of materials systems and tunable energy absorbing properties respond to a range of energy absorption needs in different impact conditions. Tunable energy absorption of bilayer cellular foams is investigated using hollow glass spheres with different wall thickness and densities. Co‐cured bilayer foams...

Inaccuracies in modeling of the geometric shape of PAMs has long been cited as a probable source of error in modeling and design efforts. The geometric shape and volume of PAMs is commonly approximated using a cylindrical shape profile, even though its shape is non-cylindrical. Correction factors—based on qualitative observations of the PAM’s gener...

The optimal control of a magnetorheological energy absorber (MREA) shock mitigation system is investigated considering quadratic damping in the MREA. To this end, the equation of motion of a single-degree-of-freedom (SDOF) shock suspension system using an MREA with quadratic damping is analyzed. To achieve a soft landing and to maintain stroking lo...

There is currently an increased interest in extending the application of McKibben actuators beyond gaseous environments and working fluids. Extensive efforts have already established force response models for pneumatically driven McKibben actuators that are independent of working fluid material properties, however, the model’s independence to worki...

Extensile fluidic artificial muscles (EFAMs) are soft actuators known for their large ranges of extension, low weight, and blocked forces comparable to those of pneumatic cylinders. EFAMs have yet to be studied in a way that thoroughly focuses on their manufacturing, experimental characterization, and modeling. A fabrication method was developed fo...

formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> $Objective:$ Energy-storage-and-return (ESAR) prosthetic feet have improved amputee mobility due to their efficient conversion of strain energy to mechanical work. However, this efficiency is typically achieved using light-weight, high-stiffness mate...

This book includes representative research from the state‑of‑the‑art in the emerging field of soft robotics, with a special focus on bioinspired soft robotics for underwater applications. Topics include novel materials, sensors, actuators, and system design for distributed estimation and control of soft robotic appendages inspired by the octopus and...

Pneumatic Artificial Muscles (PAMs) are compliant fluidic actuators, usually consisting of a tubular bladder, a braided sleeve and end fittings. PAMs have been studied extensively by researchers, however, most previous researches are focused on the axial PAMs. Herein, a pair of nonlinear models were developed based on the principle of virtual work...

This paper presents a minimum duration deceleration exposure (MDDE) control method for drop-induced shock mitigation system using a magnetorheological energy absorber (MREA) at high sink rates. The key MDDE control goal is that the payload should come to rest after fully using the available MREA stroke, that is, to accomplish a soft landing, withou...

Inerter is a two-terminal mass element, and the applied force is proportional to the relative acceleration between the terminals. According to the second class of mechanical–electrical analogy, the inerter corresponds exactly to the capacitor in the electric network. Aiming at improving the limited vibration isolation performance using the constant...

Smart materials are of significant interest and this is the first textbook to provide a comprehensive graduate level view of topics that relate to this field. Fundamentals of Smart Materials consists of a workbook and solutions manual covering the basics of different functional material systems aimed at advanced undergraduate and postgraduate stude...

Pneumatic artificial muscles (PAMs) are an extensively investigated type of soft actuator. However, the PAM motions have been limited somewhat to uniaxial contraction and extension, restraining the development of PAMs. Given the current strong interest in soft robotics, PAMs have been gaining renewed attention due to their excellent compliance and...

Objective: To understand and overcome the challenges associated with moving life-urgent payloads using unmanned aircraft. Background data: Organ transportation has not been substantially innovated in the last 60 years. Unmanned aircraft systems (UAS; ie, drones) have the potential to reduce system inefficiencies and improve access to transplanta...

The U.S. Naval Research Laboratory (NRL) has been developing a space-rated 7 degree of freedom (DOF) robot arm with a high payload-to-mass ratio as an alternative design to motor-gear driven robotic manipulators. The robot arm employs antagonistic pairs of pneumatic artificial muscle (PAM) actuators to control each degree-of-freedom (DOF) to achiev...

The U.S. Naval Research Laboratory (NRL) has been developing a space-rated 7 degree of freedom (DOF) robot arm with a high payload-to-mass ratio as an alternative design to motor-gear driven robotic manipulators. The robot arm employs antagonistic pairs of pneumatic artificial muscle (PAM) actuators to control each degree-of-freedom (DOF) to achiev...

Soft Robots achieve desired motion by deformation of their elastic links and offer the ability to adapt to unstructured environments and manipulate objects of varying sizes. Inherent elasticity and continuity allow for whole-arm operations such as grasping, wrapping and lifting without damaging the manipulated object. To find the right base orienta...

We investigated the effect of bonding temperature and duration on the microstructure development and energy absorption capacity of consolidated cellular solids, formed from hollow glass spheres. The temperatures were varied between 760 and 860 °C for 30 min and the bonding times were varied from 5 to 50 min at 810 °C. SEM micrographs were used to s...

Adaptive energy absorbers (EAs) utilizing magnetorheological fluids (MRFs) are currently being investigated for severe impact or shock mitigation problems because magnetorheological energy absorbers can adjust stroking load to account for severity of impact and payload mass. Utilizing MRFs in such EAs requires a highly stable suspension that mainta...

Robotic end effectors are needed for a variety of terrestrial and space-based tasks. End effectors are commonly inspired by the human hand, with a range of complexity, including varying number of fingers, joints and degrees of freedom. Hand and pincher-type grippers can require complicated actuation and/or a significant sensing and control system t...

The smart fluids - magnetorheological (MR) fluids show the potentials for high-speed shock mitigation applications because of their fast response and large controllable damping range. In order to match the high-speed applications of MR fluids, the structural design and controllability evaluation of MR actuators are of great significance. Controllab...

Organ transportation has yet to be substantially innovated. If organs could be moved by drone, instead of ill-timed commercial aircraft or expensive charter flights, lifesaving organs could be transplanted more quickly. A modified, six-rotor UAS was used to model situations relevant to organ transportation. To monitor the organ, we developed novel...

In this study, the time-domain model of a magnetostrictive electro-hydrostatic actuator (MEHA) is built from the viewpoint of energy conversion, which consists of four energy transformation stages: electrical-magnetic, magneto-elastic, elastic-hydraulic and hydraulic-mechanical energy transformation. Accordingly, a Jiles-Atherton hysteresis model w...

Technical, immunologic, and patient care advancements have improved transplant outcomes, but geography and organ transportation remain impediments to access to transplantation. Organs are moved using a complex network of couriers, commercial aircraft, and transplant personnel. Reliance on commercial aircraft schedules and couriers add cold ischemia...

Long strips of material cut from magnetostrictive Fe-Al (alfenol) and Fe-Ga (galfenol) rolled sheets with a preferred orientation are flexible yet have a high elastic modulus. They resemble animal whiskers and are effective as flow sensors, responding with local changes in magnetization due to bending stresses induced from the drag force during flu...

A key goal for implementation of magnetorheological fluids (MRFs) is to minimize sedimentation or to increase suspension stability. In this study, a series of MRF samples were synthesized by suspending carbonyl iron particles (CIPs), which had different organic molecules and auxiliaries grafted onto their surface, in silicone oil. The magnetorheolo...

Extensive studies have been conducted to examine the use of piezoelectric transducers and other ultrasonic devices for structural health monitoring applications due to their high electroacoustic efficiency and simple operation principles. Most studies use guided Lamb wave inspection methods to detect, locate, and characterize damage in relatively s...

This paper addresses the strain-dependent dynamic compressive properties (i.e., so-called Payne effect) of magnetorheological elastomeric foams (MREFs). Isotropic MREF samples (i.e., no oriented particle chain structures), fabricated in flat square shapes (nominal size of 26.5 mm x 26.5 mm x 9.5 mm) were synthesized by randomly dispersing micron-si...

The design and test of a magnetorheological fluid (MRF)-based universal gripper (MR gripper) are presented in this study. The MR gripper was developed to have a simple design, but with the ability to produce reliable gripping and handling of a wide range of simple objects. The MR gripper design consists of a bladder mounted atop an electromagnet, w...

Pneumatic artificial muscles (PAMs) are used in robotic and prosthetic applications due to their high power to weight ratio, controllable compliance, and simple design. Contractile PAMs are typically used in traditional hard robotics in place of heavy electric motors. As the field of soft robotics grows, extensile PAMs are beginning to have increas...

In this paper, the shock and vibration control effectiveness of the systems based on the magnetorheological (MR) energy absorber (EA) with an internal bypass is investigated and compared with a conventional MREA with an identical volume, the MREA with an internal bypass at passive-on state, and a passive EA based systems. The mechanical model of th...

The Mason number can be used to produce a single master curve which relates MR fluid stress versus strain rate behavior across a wide range of shear rates, temperatures, and applied magnetic fields. As applications of MR fluid energy absorbers expand to a variety of industries and operating environments, Mason number analysis offers a path to desig...

Based on state observation, a rapid, stable, and effective control algorithm for magnetorheological elastomer (MRE)–based dynamic vibration absorbers (DVAs) applied to automobile powertrain mount systems is proposed and investigated in this article. The state-space model for powertrain mount systems with MRE-based DVAs is established using the rank...

assive leg exoskeletons are currently being investigated for offsetting the weight of tools and other loads from work- ers performing maintenance and assembly tasks. By providing power-assist to the knee joints with pneumatic artificial muscles (PAMs), a wider range of stances could be used by maintenance workers without drawing significant power....

This study presents the improvement of a Bingham-plastic damper model incorporated with refined minor losses (BPM damper model) by considering fluid friction models so as to predict the stroking load of a magnetorheological energy absorber (MREA) during high speed impact. MREAs produce a variable stroking load that adapts to a range of payload mass...

Adaptive landing gear dampers that can continuously adjust their stroking load in response to various operating conditions have been investigated for improving the landing performance of a lightweight helicopter. In prior work, adaptive magnetorheological (MR) landing gear dampers that maintained a constant peak stroking force of 4000 lbf across si...

This study addresses an automated method and experimental apparatus to measure sedimentation of magnetorheological fluids (MRFs) in a vertical column. The Automated Vertical Axis Inductance System (AVAIMS) developed at the University of Maryland monitored the particle concentration (i.e. particle volume fraction) of a MRF as a function of column he...

The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant e...

In this paper, focusing on the application-oriented giant magnetostrictive material (GMM)-based electro-hydrostatic actuator, which features an applied magnetic field at high frequency and high amplitude, and concentrating on the static and dynamic characteristics of a giant magnetostrictive actuator (GMA) considering the prestress effect on the GM...

In this paper, we investigated the behavior of magnetorheological fluids (MRFs) by means of a custom Searle magnetorheometer. The Searle measuring system is composed of an outer stationary cylinder and an inner cylinder driven by a motor. The MRF is placed between the two concentric cylinders. While the bob is rotating, the fluid transmits a torque...

Stability of magnetorheological fluids (MRFs) or suspensions has been a key issue in the development of various practical applications. In our prior work, it was experimentally confirmed that a high viscosity linear polysiloxane carrier fluid based MRF (hereinafter HVLP MRF) with 26% particle volume fraction (hereinafter 26 vol%) showed high sedime...

This study develops the design analysis and control of adaptive magnetorheological landing gear dampers (MRLGDs) to enable adaptive shock mitigation in a lightweight helicopter. MRLGDs were designed to achieve a desired stroking load of 4000 lb (17.8 kN) over a desired equivalent sink rate range of 6-12 ft/s (1.83-3.65 m/s). The design analysis at...