Magnetorheological Elastomer Research Articles

Toward Onboard Proportional Control of Multi-Chamber Soft Pneumatic Robots: A Magnetorheological Elastomer Valve Array.

Soft pneumatic actuators (SPAs) are commonly used in various applications because of their structural compliance, low cost, ease of manufacture, high adaptability, and safe human-robot interaction. The traditional approach for achieving proportional control of soft pneumatic robots requires the use of industrial proportional valves or syringe drivers, which are not only rigid and bulky but also hard to be integrated into the body of soft robots. In our previous research, we developed a Magnetorheological elastomer (MRE)-based soft valve that showed advantages for controlling SPAs due to its compliance, compactness, robustness, and compatibility for continuous pressure modulation. Modern soft robots with multiple chambers require more MRE valves onboard for their control. However, merely packing more MRE valves for soft robots can cause problems like magnetic interference, flow rate deviation, and overheating. Therefore, in this study, we proposed a two-dimensional MRE valve array design to solve issues of magnetic interference and overheating when expanding from a single MRE proportional valve into an integrated array. The magnetic interference and the overheating problem were investigated through multiphysics simulation, bringing the optimal choice of valve spacing (1.2 times the single valve diameter), magnetic coil pole arrangement (same pole), and the cooling system design (internal cooling chamber with flowing water). Physical experiments showed that our MRE valve array maintained its original flowrate performance with low magnetic interference (0.89 mT) and low coil temperature (under 73.9°C for 5 min).

Magnetorheological response of Permalloy@ styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene elastomers as a function of filler concentration

AbstractDeveloping advanced magnetorheological elastomers (MREs) with a range of specific characteristics is essential for matching the growing demands from a wide spectrum of applications such as automotive, healthcare, sensors, and actuators. However, the compatibility problems between constituents and the low magnetorheological (MR) effect have limited their performance and integration into actual applications. Here, a novel MRE consisting of styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) and Ni‐rich Permalloy (Ni80Fe17Mo3) has been developed with remarkable functional properties. The correlation between the filler concentration and microstructural, mechanical, thermal, magnetic, and MR properties is reported. The incorporation of Ni‐rich Permalloy has a reinforcement effect in the polymer matrix and leads to an improvement of the thermal stability. Further, the saturation magnetization and remanence of the composites increase with increasing filler content. In particular, the saturation magnetization increases from 14.3 to 41.9 A m2/kg, and the remanence from 1.2 to 4.0 A m2/kg when the concentration increases from 20 to 60 wt%. Finally, the MR effect of composites with 20, 40, and 60 wt% filler content is 8%, 15%, and 35%, respectively. A magnetic dipole interaction model is used to discuss the MR effect and a relation between the MR effect and the main parameters affecting it is proposed. Importantly, the obtained MR values are higher when compared with related composites for the same magnetic content, and for the same or similar polymeric matrices, demonstrating the suitability of the developed materials for the fabrication of high‐response functional MR devices.

Adjusting dynamic and damping performance in fiber-reinforced magnetorheological elastomer composite conical shells subjected to compressive loads

This study explores the dynamic behavior of axially loaded conical shells composed of magnetorheological elastomer composites (MRECs). The investigation focuses on analyzing the impact of compressive loads on the frequencies and loss factors of these composites. The MRECs consist of laminates reinforced with fibers, enabling tunable viscoelastic properties through the utilization of magnetic fields. The equivalent mechanical characteristics of the MREC are calculated using the modified Voigt and Halpin–Tsai micromechanical rules. By employing the first-order shear deformation theory and Sanders-based strains, the kinematics of the conical shell are accurately modeled. A semi-analytical analysis, combining trigonometric expansion and the generalized differential quadrature (GDQ) methods, is employed to solve the system's highly coupled partial differential equations. Two consecutive analyses are performed. Firstly, the critical buckling load of the MREC conical shell is obtained through a stability analysis. Subsequently, the frequencies and loss factors of the shell in the pre-buckling zone are computed. Parametric analyses are conducted to study the impact of key factors, including magnetic field strength, compressive load magnitude, composite properties, geometric parameters, and boundary conditions. The proposed methodology is rigorously validated through meticulous accuracy and convergence analysis. The outcomes provide valuable insights into the dynamic response of axially loaded magnetorheological elastomer composite conical shells, highlighting their potential in adjustable dynamic and damping systems.

A Comparative Study on Various ANN Optimization Algorithms for Magnetorheological Elastomer Carbonyl Iron Particle Concentration Estimation

Estimation particle composition such as particle shape, size, and concentration are crucial prior to the fabrication process of magnetorheological elastomer (MRE) to avoid process repetition due to inaccurate formulation. Currently, most of MRE prediction model were purposely used to predict the rheological properties such as shear stress and dynamic modulus, known as forward model. Nonetheless, very few studies have been reported to be capable able of predicting particle composition particularly in MR materials, which known as inverse model. Therefore, this paper proposed a carbonyl iron particle (CIP) concentration based MRE prediction model using neural network algorithm. Neural network-based machine learning model is more approachable compared to conventional mathematical modelling approach due to easily identify trends and pattern while handling multi-variety data. Various optimization algorithms have been employed such as Adam, RMSprop, SGD, AdaGrad, and Nadam throughout the modelling process. As the results, given shear strain amplitude, magnetic flux density, storage modulus, and loss factor as model input, SGD gave the maximum prediction accuracy with 0.95 and 3.038 MPa of R2 and RMSE, respectively. Hence, this model can be the basis to the MRE material and devices development particularly as the tool to reduce costing and time consuming.

Tensile Properties of Isotropic and Anisotropic Magnetorheological Elastomer With and Without Magnetic Field Application

In this study, two variations of magnetorheological elastomer (MRE) tensile specimens were fabricated, differing in their isotropic and anisotropic configurations. The isotropic MRE exhibited randomly dispersed carbonyl iron particle (CIP), whereas the anisotropic featured longitudinally aligned CIP particles along the gauge length of the tensile sample. The formation of the anisotropic MRE involved utilizing an electromagnetic curing chamber, which facilitated the alignment of CIP particles during the elastomer curing process. A mold was specifically designed to produce samples conforming to the dimensions outlined in ASTMD412-F. Subsequently, a Finite Element Method Magnetics (FEMM) analysis was conducted to examine the magnetic flux within the curing device for the anisotropic MRE. Uniaxial tensile tests were conducted on both MRE types, both in the absence and presence of a 30 mT magnetic field applied transversely to the direction of CIP alignment. Results indicated that without a magnetic field, the anisotropic sample exhibited a slightly higher tensile strength, lower elongation, and higher modulus at 100% strain. However, when a magnetic field was introduced, the isotropic sample demonstrated a more pronounced increase in tensile strength, showing an 18.4% improvement compared to the 5.6% increase observed in the anisotropic sample. Similar trends were observed in the reduction of elongation, with a 14% decrease for isotropic and a 7% decrease for anisotropic samples. Additionally, the data on modulus at a 100% strain revealed a 22.3% increase in stiffness for the isotropic sample, while the anisotropic sample showed a 10.6% increase.

Flutter analysis of laminated fiber-reinforced magnetorheological elastomer sandwich plate resting on an elastic foundation using an improved first-order shear deformation theory

Magnetorheological elastomers (MREs) are polymers with viscoelastic properties that can be adjusted by manipulating the magnetic field. When MREs are combined with reinforcing fabrics, a new category of materials known as MRE composites (MRECs) can be created, which not only possess the characteristics of MREs but also enhance their rigidity. This study focuses on investigating the supersonic aeroelastic instability of a rectangular sandwich plate with a laminated MREC core layer and functionally graded materials with porosities as face layers. Additionally, the sandwich plate is supported by an elastic foundation and subjected to supersonic airflow. This investigation presents an improved first-order shear deformation theory, postulating a parabolic distribution of shear stresses. Consequently, the transverse shear stresses are rendered as zero at the surface of every individual layer; thus, the requirement for shear correction in this theory is eliminated. In addition, 8-node elements are implemented to circumvent the necessity for distinct handling of shear-locking. The aeroelastic pressure acting on the structure is considered using first-order piston theory. Micromechanical approaches, such as Halpin‐Tsai and rule of mixture approaches, are employed to determine the effective mechanical properties of the core and face layers. The dynamic equations of the structure are derived using Hamilton’s principle and the finite element method. The study also examines the impact of different magnetic fields, fiber volume fraction, elastic foundation factors, layering angles, geometry, and boundary conditions on flutter frequency.

Vibration analysis of a rotor-bearing system using magneto-rheological elastomers

Magneto rheological materials are considered as a promising adaptive means of vibration control. This paper proposes a new configuration of smart bearings comprising magneto-rheological elastomer (MRE) layer inserted between the bearing pedestal and the foundation. This configuration provides a directional vibration controllability in both horizontal and vertical directions of a rotor-bearing system. The effect of using MRE layer on the vibration response and the resonant speeds of a rotor-bearing system is investigated. The finite element method is used to derive a dynamic model for the rotor-bearing system using shaft elements based on the Rayleigh beam theory and accounting for the gyroscopic effect and internal damping of the shaft. Simulation results reveal that the use of MRE materials in passive mode leads to downshifting of the first two resonant speeds and the attenuation of the steady state vibration response of the rotor bearing system in the horizontal and vertical directions at the resonance frequencies. When the MRE layer is subjected to a magnetic field generated by an electric current produced in the magnetic coil, the horizontal and vertical vibration responses are increased at the resonant speeds but decreased at other rotational speed ranges. Furthermore, the first two resonant speeds in the horizontal and vertical directions decrease further with the increase of the electric current.

Stability analysis of multi-trigger nano tube sandwich structures considering thermal and magnetic effects

This research investigates the stability analysis of multi-trigger nanotube-based sandwich structures that carry fluid subjected to external stimulus. Acrylic-based material and magnetorheological elastomers (MRE) are considered multi-trigger cores in which the external stimulus alters the mechanical properties of the core and, subsequently, the sandwich structures. The system is subjected to an external magnetic field while the ambient temperature varies. The results demonstrate that incorporating a multi-trigger viscoelastic core can accelerate the divergence instability of the non-conservative system while delaying its flutter. Additionally, the impact of the external magnetic field, as a control parameter, for the frequency and stability region of the MRE is more significant than that of the Acrylic-based material. Furthermore, employing Acrylic-based material with a higher shear modulus in a constant magnetic field leads to a more stable system. Moreover, the effect of the external magnetic force on stability is affected smoothly by the ambient temperature. Finally, the influence of temperature on stability is nearly the same for both MRE and Acrylic-based material, with a more pronounced effect observed in systems with larger length-to-diameter ratios.

Shear stiffening and magneto-induced properties of magnetorheological elastomer based on self-healing poly(urethane-urea) matrix

A novel multifunctional composite material, defined as self-healing magnetorheological elastomer (SH-MRE), which exhibits both shear stiffening and magnetorheological effects as well as self-healing ability, is obtained by dispersing carbonyl iron particles in a poly(urethane-urea) matrix. The dynamic shear properties are tested through oscillation frequency and magnetic field sweeps. When shear stress is applied with an excitation frequency of 0.1 Hz to 100 Hz, the storage modulus of the poly(urethane-urea) matrix increases sharply, showing a good shear stiffening effect. In addition to the magnetically dependent mechanical properties with a magnetic flux density of 0–0.894 T, the self-healing efficiency of the isotropic SH-MREs with destructive shear damage after healing can be influenced by the mass fraction of the carbonyl iron particles, the applied magnetic field strength and the support of trace solvents. Based on the experimental results, it is believed that the hydrogen bonds in the dynamic hard domains and the magnetic interaction forces between the carbonyl iron particles induced by the magnetic field are the cause of the good multifunctional properties.

Head-Up Haptic Display Using Dual-Mode Haptic Actuator for Vehicles

Driving assistance modules are important components to improving driver safety in driving environments, which can create overloaded multisensory information. This paper introduces the concept of a head-up haptic display that assists drivers in keeping their visual attention focused, and then offers a haptic actuator that may be used as the main component in the head-up haptic display. We selected magneto-rheological elastomer (MRE) as the base material and adopted a porous structure to reduce its initial stiffness. Furthermore, we fabricate a haptic actuator based on an MRE having a porous structure (pMRE) and a solenoid. The current to the solenoid generates a magnetic field that causes the pMRE to stiffen, thereby increasing the resistive force. As soon as the current input is removed, the pMRE becomes soft again. We simulated the solenoid coil and the magnetic path to further maximize the magneto-motive force generated by the solenoid coil and experimentally optimized the pMRE. We showed that the proposed haptic actuator creates not only a sufficient resistive force but also vibration to generate various haptic sensations. Moreover, we constructed a head-up haptic display using four haptic actuators and demonstrated the possibility of utilizing a new user interface to increase driving safety.

Magnetic-Control Variable Stiffness and Damping Tail Support for a Wind-Tunnel Aircraft Model

To suppress random vibration of aircraft models during wind tunnel tests, a novel magnetorheological elastomer (MRE)-based device with variable stiffness and variable damping (VSVD) is proposed, which is installed on the tail support system. Firstly, the dynamic characteristics of the tail support system are established using finite element model simulation to obtain the vibration mode and stress distribution. Next, the vibration reduction mechanism of the MRE-based tail support system is analyzed by solving a finite element model. Then, the magnetic-controlled VSVD device with an annular sandwich structure is proposed, and the decisive rheology material and structural parameters in relation to the tail support system’s dynamics are determined. Subsequently, the magnetically generated element with multicoils is designed to guarantee a large enough magnetic field, and the optimal structure parameters are obtained. Finally, random wind flow experiments in the wind tunnel and frequency sweep tests in the ground laboratory for the tail support system equipped on the VSVD device are conducted to verify the effectiveness of the proposed device, respectively. The results under 15–200 Hz random excitation indicate the root mean square of acceleration at the centroid of the aircraft model with the VSVD device can be decreased by 46.8% compared to the system without the VSVD device.

Distinct cytoskeletal regulators of mechanical memory in cardiac fibroblasts and cardiomyocytes.

Recognizing that cells "feel" and respond to their mechanical environment, recent studies demonstrate that many cells exhibit a phenomenon of "mechanical memory" in which features induced by prior mechanical cues persist after the mechanical stimulus has ceased. While there is a general recognition that different cell types exhibit different responses to changes in extracellular matrix stiffening, the phenomenon of mechanical memory within myocardial cell types has received little attention to date. To probe the dynamics of mechanical memory in cardiac fibroblasts (CFs) and cardiomyocytes derived from human induced pluripotent stem cells (iPSC-CMs), we employed a magnetorheological elastomer (MRE) cell culture substrate with tunable and reversible stiffness spanning the range from normal to diseased myocardium. In CFs, using increased cell area and increases in α-smooth muscle actin as markers of cellular responses to matrix stiffening, we found that induction of mechanical memory required seven days of stiff priming. Both induction and maintenance of persistent CF activation were blocked with the F-actin inhibitor cytochalasin D, while inhibitors of microtubule detyrosination had no impact on CFs. In iPSC-CMs, mechanical memory was invoked after only 24h of stiff priming. Moreover, mechanical memory induction and maintenance were microtubule-dependent in CMs with no dependence on F-actin. Overall, these results identify the distinct temporal dynamics of mechanical memory in CFs and iPSC-CMs with different cytoskeletal mediators responsible for inducing and maintaining the stiffness-activated phenotype. Due to its flexibility, this model is broadly applicable to future studies interrogating mechanotransduction and mechanical memory in the heart and might inform strategies for attenuating the impact of load-induced pathology and excess myocardial stiffness.

Layer Jamming of Magnetorheological Elastomers for Variable Stiffness in Soft Robots

BackgroundOne of the biggest challenges in soft robotics is the variability and controllability of stiffness. Jamming-based approaches have been of interest to change stiffness dramatically by increasing friction between grains, layers, or fibers. Besides, magnetorheological elastomers (MREs) that exhibit magnetic field-dependent viscoelasticity have significant potential as a stiffness variation material. This study investigates the unique mechanics of magnetic jamming of MRE sheets exploring stiffness change both due to jamming and variable viscosity.MethodsSample MREs and flexible neodymium-iron-boron (NdFeB) magnets are manufactured. Uniaxial tensile tests supported with digital image correlation are performed to characterize the materials. Multi-layer jamming structures comprised of MREs and NdFeB magnets are developed and validated through 3-point bending experiments and finite element simulations.ResultsResults show that the stiffness of the multi-layer structure is higher under magnetic field. Furthermore, the stiffness change is increased when MREs are used instead of PDMS as layers.ConclusionThis study proves the concept of magnetic jamming of MRE layers. The results are crucial for the possible soft robotic implementation of the proposed hybrid stiffening approach combining jamming with viscoelasticity modification.

Adaptive beam with elastic support based on magnetorheological elastomers for modal modulation and vibration suppression

Owing to the wide modulation capability of their magneto-induced modulus, smart structure-based magnetorheological elastomers (MREs) show great promise for vibration control in numerous engineering applications. In conventional smart structure-based MREs, however, vibration absorption or isolation is mainly used for discrete structural systems, and the requirement for vibration control in continuous structures can limit the application of vibration absorbers and isolators. Therefore, it is necessary to resolve the dynamic properties of the continuous structure to obtain modal information. In this paper, different types of smart beams with adaptive elastic support (AES)-based MREs, containing dual-end elastic support, single-end elastic support, and the combination of a fixed end and an AES at an arbitrary location, are developed to tactically influence the dynamics through magneto-mechanical coupling. A dynamic model of thin-walled beams with AES was established by using the improved Fourier series method (IFSM). The numerical results confirm that the effective suppression bandwidth of the beam with MRE-AES can be shifted as a result of the modal modulation-induced energy transfer from low to high frequencies, which requires a decreasing trend of modal amplitude at the response location as the elastic support stiffness increases. According to the modal analysis, the beams with single-end AES and dual-end AES have a decreasing trend of modal amplitude in the global location as stiffness increases. However, the modal amplitude trend of the beam with a fixed end and an AES is not monotonic at certain locations. The experimental results demonstrate that MRE-AES can effectively attenuate the acceleration responses of the beams with single-end AES and with a fixed end and an AES under harmonic excitation. The resonance peaks in the transmission remarkably shift to higher frequencies with increasing magnetic flux.

Anisotropic nanoparticle-based magnetorheological elastomers: Effect of shape and orientation on the magnetorheological performance

Magnetorheological elastomers (MREs) respond to applied magnetic fields with a change in their mechanical properties. Within this work, iron oxide nanorods (IONRs) have been synthesized and the suitability of anisotropic nanoparticles to obtain highly responsive isotropic and anisotropic MREs has been demonstrated. Electron microscopy images show that the IONRs are well distributed inside the styrene-ethylene-butylene-styrene (SEBS) polymeric matrix and can be successfully oriented. The elastic modulus of the composites increases twofold with respect to the bare polymer. Room temperature magnetization loops of the composites show a difference in the orientations, with variations of the anisotropy field from 39.2 kA m−1 to 67.7 kA m−1. Magnetorheology measurements show that the relative magnetorheological effect experiences a twofold increase for the anisotropic MREs, from 8.3% to 17%. This, along with the improved mechanical properties of the anisotropic MREs, offers excellent possibilities for the design of high performance MREs that work optimally in the elastic region and possess improved applicability.

An improved model of magnetorheological elastomer of frequency, magnetic field, and amplitude responses

An improved model of magnetorheological elastomer of frequency, magnetic field, and amplitude responses

Stretchable Magneto-Mechanical Configurations with High Magnetic Sensitivity Based on "Gel-Type" Soft Rubber for Intelligent Applications.

"Gel-type" soft and stretchable magneto-mechanical composites made of silicone rubber and iron particles are in focus because of their high magnetic sensitivity, and intelligence perspective. The "intelligence" mentioned here is related to the "smartness" of these magneto-rheological elastomers (MREs) to tune the "mechanical stiffness" and "output voltage" in energy-harvesting applications by switching magnetic fields. Hence, this work develops "gel-type" soft composites based on rubber reinforced with iron particles in a hybrid with piezoelectric fillers such as barium titanate. A further aspect of the work relies on studying the mechanical stability of intelligence and the stretchability of the composites. For example, the stretchability was 105% (control), and higher for 158% (60 per 100 parts of rubber (phr) of barium titanate, BaTiO3), 149% (60 phr of electrolyte iron particles, EIP), and 148% (60 phr of BaTiO3 + EIP hybrid). Then, the magneto-mechanical aspect will be investigated to explore the magnetic sensitivity of these "gel-type" soft composites with a change in mechanical stiffness under a magnetic field. For example, the anisotropic effect was 14.3% (60 phr of EIP), and 4.4% (60 phr of hybrid). Finally, energy harvesting was performed. For example, the isotropic samples exhibit ~20 mV (60 phr of BaTiO3), ~5.4 mV (60 phr of EIP), and ~3.7 mV (60 phr of hybrid). However, the anisotropic samples exhibit ~5.6 mV (60 phr of EIP), and ~8.8 mV (60 phr of hybrid). In the end, the composites prepared have three configurations, namely one with electro-mechanical aspects, another with magnetic sensitivity, and a third with both features. Overall, the experimental outcomes will make fabricated composites useful for different intelligent and stretchable applications.

Fiber Jamming of Magnetorheological Elastomers as a Technique for the Stiffening of Soft Robots

There has been a notable focus on the adoption of jamming-based technologies, which involve increasing the friction between grains, layers, or fibers to achieve variable stiffness capability in soft robots. Additionally, magnetorheological elastomers (MREs) that show magnetic-field-dependent viscoelasticity have great potential as a material for varying stiffness. This study proposes a hybrid method (magnetic jamming of MRE fibers) for enhancing the stiffness of soft robots, combining a jamming-based with a viscosity-based method. First, a fiber jamming structure is developed and integrated into a soft robot, the STIFF-FLOP manipulator, to prove the concept of the magnetic jamming of MRE fibers. Then, based on the proposed method, a variable stiffness device actuated by electro-permanent magnets is developed. The device is integrated into the same manipulator and the electronically controlled magnetic jamming and stiffening of the manipulator is demonstrated. The experimental results show that stiffness gain in bending and compression is achieved with the proposed method. The outcomes of this investigation demonstrate that the proposed hybrid stiffening technique presents a promising avenue for realizing variable and controllable stiffness in soft robots.

Investigation of the performance of dopamine‐modified carbon fiber‐reinforced natural rubber‐based magneto‐rheological elastomers

AbstractFive types of magneto‐rheological elastomers (MREs) based on natural rubber were synthesized by incorporating carbonyl iron particles (CIP) as the primary filler. The objective was to investigate the influence of carbon fiber and magnetic particle content on the mechanical and magneto‐rheological properties of the MREs. Carbon fibers (CF) were further added as secondary reinforcement pre‐modified with polydopamine. The composite's microstructure was examined through scanning electron microscopy (SEM), while the mechanical and magnetodynamic properties were assessed using an electronic universal testing machine and an advanced rotational rheometer. The addition of appropriate amounts of CIP and CF resulted in increased rubber modulus, indicating the formation of a filler‐rubber network and the synergistic effect between carbon fibers as a supporting structure and CIP. Compared to the unfilled MREs, the mechanical and magnetodynamic properties were further improved by adding 2 and 4 wt% CF. These findings demonstrate that employing carbon fibers as reinforcing fillers and incorporating suitable magnetic fillers can enhance the magnetic and mechanical properties of the materials, providing a theoretical basis for the study of MREs' performance.Highlights CF and CIP synergistically enhance the strength of the rubber matrix. The MR effect is gradually enhanced with the increase of CIP content. Modified CF has a promoting effect on the magnetic responsivity. Magnetic responsivity increases with increasing modified CF content. Improved mechanical and magnetodynamic properties of composites.

Morphological features of magnetorheological elastomer degradation under a natural weathering environment

It is well known in the field of materials science that a substance’s longevity is significantly influenced by its environment. Everything begins with the initial contact on a material’s surface. This influence will then deteriorate and have an extended negative impact on the strength of the material. In this study, the effect of natural weathering in tropical climates on magnetorheological elastomer (MRE) was investigated through microstructural evaluation to understand the aging behavior of the environmentally exposed MRE. To understand and elucidate the process, MREs made of silicone rubber and 70 wt% micron-sized carbonyl iron particles were prepared and exposed to the natural weathering of a tropical climate for 90 days. The MRE samples were then mechanically tensile tested, which revealed that Young’s modulus increased, while elongation at break decreased. Surface degradation due to weathering was suspected to be the primary cause of this condition. Using scanning electron microscopy (SEM), the degradation of MRE was investigated as a function of morphological evidence. Upon examination through SEM, it was noted that the weathering effects on the morphology of the exposed samples showed distinct characteristics on the degraded surfaces of the MRE, including numerous microvoids, cavities, and microcracks. While these features were not prominent for the MRE itself, they bear resemblance to the effects observed in similar materials like rubber and elastomer. An atomic force microscope (AFM) is used to investigate the surface topography and local degradation conditions. This observation revealed a distinctive degradation characteristic of the MRE in connection to natural weathering in tropical climates. The surface damage of the MRE samples became severe and inhomogeneous during the environmental aging process, and degradation began from the exposed MRE surface, causing the mechanical characteristics of the MRE to significantly change.