Soft Materials Research Articles

Investigation of shaded pole stator topology for low power AC motors design

PurposeThis paper aims to investigate the features of single phase shaded pole stator with squirrel–cage rotor or permanent magnet rotor, that leads to an investigation of these topoloties as induction motor or synchronous motor. The comparative analysis is realised for the following three topologies: single phase shaded pole induction motor (SPIM) with squirrel–cage rotor, the second topology (single phase synchronous motor) has the same stator configuration but with permanent magnet rotor and the third investigated topology is similar to the second one, where the stator poles instead of iron steel are made of soft composite material.Design/methodology/approachThe investigation in this work starts with a performance analysis of single-phase SPIM. Afterwards for the same stator topology the squirrel rotor is replaced with a two-pole permanent magnet rotor and the same performance analysis is realised for this topology. Finally, the second topology is improved bay replacing the iron steel stator poles with stator poles made of soft magnetic composite material and performance analysis is realised for this third type of topology as well. The performance analysis of all topologies is realised by implementation of finite element method and finite element analysis.FindingsThe presented data and diagrams from the realized investigation show that single phase synchronous motor with shaded pole stator has an improved characteristics in comparison with the initial single-phase SPIM. Finally, the third topology realized on the bases of the single-phase synchronous motor has the best performance characteristics due to the implementation of soft magnetic material in the realization of the stator poles. The proposed methodology for structural and performance improvement of a single-phase SPIM topology opens the possibility for additive manufacturing application and significant cost reduction.Originality/valueThe focus was put on exploration the possibilities of the single-phase shaded pole stator topology for application in low-power and low-cost single phase self-starting motors. By simple replacement of the squirrel–cage rotor, in the reference AKO-16 motor, with one-piece ferrite permanent magnet rotor, the self-starting single phase synchronous motor was derived. In the next step, owing to simplify the SPPM motor production process and manufacturing, the stator poles instead of iron steel lamination were made of soft composite material Somaloy®. It opens the possibility for additive manufacturing application and significant cost reduction.

Viscous dissipation effects on time-dependent MHD Casson nanofluid over stretching surface: A hybrid nanofluid study

The study of MHD Couple stress Casson flow of a hybrid nanofluid is paramount due to its potential applications in advanced engineering systems, particularly in enhancing thermal management and efficiency in various industrial processes. In this report, the time-dependent MHD Couple stress Casson flow of a hybrid nanofluid, considering the impact of viscous dissipation over a stretching surface is presented. The main objective of this work is to enhance the transformation heat ratio to meet the requirements of the engineering and manufacturing industries. After conducting a continuity check, the issue is analyzed by applying the principles of momentum and energy conservation. This modeling process generates nonlinear partial differential equations (PDEs), which are subsequently converted into nonlinear ordinary differential equations (ODEs) using similarity transformation and thermophysical characteristics. To solve these ODEs, the Approximate Analytical Method HAM is employed, which is specifically designed for nonlinear problems. Velocity decreases with increasing values and higher nanoparticle volume fraction further slows the velocity. Increasing the couple-stress parameter reduces velocity; increasing the Casson parameter slows the velocity profile. Increasing magnetic parameter enhances temperature profile; profile escalates with Eckert number magnitude. These findings contribute significantly to understanding the structure, interactions, and dynamics of such liquids, aligning with the focus on exploring the fundamental properties of simple, molecular, ionic, and complex liquids.

Extensive data analysis and modelling of carbon dioxide solubility in ionic liquids using chemical structure-based ensemble learning approaches

The significant rise in carbon dioxide (CO2) emission due to industrial growth is a major global challenge. As a result, there is a need to implement various techniques to reduce and regulate this phenomenon. One such technique involves the utilization of ionic liquids (ILs) as solvents in CO2 capturing and separation processes, which is already commonly practiced. In this study four advanced intelligent models, Extreme Gradient Boosting (XGBoost), Gradient Boosting (GBoost), Light Gradient Boosting Machine (LightGBM), and Categorical Boosting (CatBoost) have been proposed to predict the solubility of CO2 in 160 different ILs based on factors such as temperature, pressure, and the chemical structure of the ILs. Findings indicate that the XGBoost model is the most accurate among the four models, with the root mean square error (RMSE) and coefficient of determination (R2) values of 0.014 and 0.9967, respectively. Moreover, the results reveal that increasing pressure, decreasing temperature, and lengthening the alkyl chain all increase the solubility of CO2 in ILs. Furthermore, pressure and the number of –CH2 substructure in ILs have the most significant impact on the CO2 solubility in ILs, respectively. To ensure the XGBoost model's reliability, the model's data has been assessed using the leverage technique. The results show that 92.44 % of the data fell within the valid area, which is a substantial percentage and indicates the model's high reliability. The findings of this study will assist in designing and fine-tuning the chemical structure of ionic liquids specifically for CO2 capture purposes.

2D Photonic Colloidal Liquid Crystals Composed of Self-Assembled Rod-Shaped Particles.

Photonic crystals, characterized by their periodic structures, have been extensively studied for their ability to manipulate light. Typically, the development of 2D photonic crystals requires either sophisticated equipment or precise orientation of spherical nanoparticles. However, liquid-crystalline (LC) materials offer a promising alternative, facilitating the formation of periodic structures without the need for complex manipulation. Despite this advantage, the development of 2D photonic periodic structures using LC materials is limited to a few colloidal nanodisk liquid crystals. Herein, 2D photonic colloidal liquid crystals composed of biomineral-based nanorods and water is reported. The soft photonic materials with 2D structure by self-assembled LC colloidal nanorods are unique and a new class of photonic materials different from conventional solid 2D photonic materials. These colloids exhibit bright structural colors with high reflectance (>50%) and significant angular dependency. The structural colors are adjusted by controlling the concentration and size of the LC colloidal nanorods. Furthermore, mechanochromic hydrogel thin films with 2D photonic structure are developed. The hydrogels exhibit reversible mechanochromic properties with angular dependency, which can be used for an advanced stimuli responsible sensor.

Magnetic arthropod soft robot with triboelectric bionic antennae for obstacle identifying and avoidance

Magnetic soft robots exhibit attractive advantages such as nontethered constraints and remote control capabilities, with broad prospects in environmental exploration, minimally invasive surgery and other fields. However, constrained by the magnetic control mode and the high flexibility of the soft materials, achieving rapid movement and perception-feedback of magnetic soft robots are still challenging. Therefore, this paper aims to draw inspiration from biomimetic joint structures to design and fabricate a magnetic arthropod soft robot capable of rapid cyclic extension-contraction deformation under an alternating magnetic field. First, a type A magnetic arthropod soft robot (MASR-A) is developed with a speed up to 1.4 body length per second (BL/s) with three-joint-unit. Next, we designed a type B magnetic arthropod soft robot (MASR-B) that offers higher flexibility and deformation adaptability with bodies owing five-joints structure. Then, inspired by snail’s tentacles, we developed bionic antennae based on triboelectric tactile sensors (TTSs), which can convert external mechanical collisions into electrical signals output, with a sensitivity of up to 0.13 V KPa−1. By mounting the bionic antennae on the head of MASR-B to realize the magnetic soft robot’s sensing function, enabling MASR-B to detect collisions with obstacles of various materials (PMMA, Resin, PLA and etc.). Particularly, the bionic antennae consists of two completely independent triboelectric sensing units (LTTS and RTTS). The signals from these two TTSs are received and identified by a microcontroller to determine the direction of obstacle relative to the robot. The relay is then controlled to alter the magnetic field generated by the electromagnetic coils to enable MASR-B to avoid obstacle. This paper provides a biomimetic design approach for the rapid movement and flexible sensing of magnetic soft robots.

A new photoacoustic method to study diffusion in soft matter

We describe an improvement to the photoacoustic method for determining diffusion coefficients of dyes in soft matter, such as agar hydrogels. The proposed method is based on the properties of thermal wave formed due to a heat transfer at the interface of the two media: the gel and polyethylene film. It is inherently simple, requires a small number of reagents and relatively fast, since samples are small. To assess the obtained results, we independently determined diffusion coefficients of the dyes using an optical image analysis method and found both sets of results to be in a good agreement.

Emulsion gel-based inks for 3D printing of foods for dysphagia patients: High internal type emulsion gel-biopolymer systems

High internal type emulsion gels (HIPE gels) are usually a soft semi-solid material consisting of tightly packed oil droplets stabilized by a layer of emulsifier. The semi-solid nature of HIPE gels means they can be used as edible inks in 3D food printing applications. However, the rheological properties of HIPE gels are typically unable to satisfy the demands of 3D printing applications, resulting in unsatisfactory printing performance. In this study, HIPE gel-based inks (85% by volume of oil) with improved 3D printing performance were prepared by using pea protein-inulin complexes as emulsifiers. In addition, the effects of oil type (corn, sunflower, flaxseed, or olive oil) on the 3D printing property, rheological properties, and microstructure of the HIPE gels was analyzed since different oils have different nutritional and physicochemical properties. Moreover, International Dysphagia Diet Standardization Initiative (IDDSI) foods created by 3D printing with these edible inks were evaluated in a population of the elderly suffering from dysphagia. It was found that HIPE-based edible inks containing an optimized inulin level (0.75% w/v) had the best 3D printing properties. In terms of oil type, the edible inks formulated from corn oil and from flaxseed oil had the best 3D printing property. As analyzed in the Lissajous plot, the addition of inulin remarkably improved the viscoelasticity of the inks, which improved their 3D printing property. These inks also exhibited high thixotropic recovery and good thermal stability. Moreover, cryo-SEM analysis showed that the PPI-inulin complex formed a barrier on the oil droplets' surface and a dense cross-linked structure between the particles. The IDDSI evaluation found that the HIPE gel inks were able to satisfy the requirements of Class IV and V foods in the IDDSI framework and could be classified as transitional foods, which would satisfy the food needs of patients with dysphagia.

A hyperelastic strain energy function for isotropic rubberlike materials

A three parameter novel hyperelastic strain energy function is introduced in this paper for soft and rubber-like materials. The function integrates a non-separable exponential component with a single term Ogden-type polynomial-like function, resulting in an exponential-polynomial based strain energy function. This helps in capturing both small and large deformation (stretch) behaviours of hyperelastic materials. The structure of the model is simple and validated against several experimental datasets including rubbers, hydrogel, and soft tissues. The model is reported to capture key material behaviors, including strain stiffening and various deformation paths. Through comparative studies with well-known models like the Ogden (six parameters) and Yeoh (three parameters), the model’s effectiveness is established. Furthermore, the model successfully addresses pressure-inflation instability in thin spherical balloons. It’s applicability extends to biological materials, as evidenced by its effectiveness in characterizing porcine brain tissue and a monkey’s bladder.

Lateral buckling of the compressed edge of a beam under finite bending

This paper investigates the critical condition whereby the compressed edge of a beam subjected to large bending exhibits a sudden lateral heeling. This instability phenomenon occurs through a mechanism different from that usually studied in linear theory and known as flexural–torsional buckling. An experimental test device was specifically designed and built to perform pure bending tests on soft materials. Thus, the experimental campaign provides not only the moment-curvature behavior of beams of narrow rectangular cross section, but also information regarding the post-critical lateral buckling behavior. To study the local bifurcation phenomenon, an analytical model is proposed in which a field of small transversal displacements, typical of the linear stability of thin plates, is superimposed on the large vertical displacement field of an inflexed beam in the nonlinear elasticity theory. Furthermore, numerous numerical simulations through nonlinear FE analysis have been performed. Finally, the results provided by the different methods applied were compared and discussed.

In vitro Models for Predicting Bioadhesion Fracture Strength to Ex Vivo Animal Buccal Tissue.

Commitment to the 3Rs principle (Replacement, Reduction, and Refinement) led to the development of a cell-based system to measure buccal bioadhesion in vitro and replace the use of porcine buccal and esophageal tissues (PBT and PET, respectively). Additionally, the aim is to bridge the gap in knowledge regarding the bioadhesion properties of PBT and PET. The in vitro models are based on the human buccal epithelial cell line-TR146 without ("Model I") or with ("Model II") 5% (w/v) mucous layer. The in vitro setup also provides a method to evaluate the bioadhesion between two soft materials. Standard bioadhesive hydrogels (alginate, chitosan, and gelatin) are used to test and compare the results from the in vitro models to the ex vivo tissues. The ex vivo and in vitro models show increased bioadhesion as the applied force and contact time increases. Furthermore, Model I exhibits bioadhesion values-of alginate, chitosan, and gelatin-comparable to those obtained with PBT. It is also found that contact time and applied force similarly affect PBT and PET bioadhesion, while PET exhibits greater values. In conclusion, Model I can replace PBT for measuring bioadhesion and be incorporated into the experimental design of bioadhesive DDS, thus minimizing animal tissue usage.

Study and Application on the Electromagnetic Stainless Steel: Microstructure, Tensile Mechanical Behavior, and Magnetic Properties.

Stainless steel grade 430 is a type of soft magnetic electromagnetic material with rapid magnetization and demagnetization properties. Considering the delay phenomenon during operation, this study selected 430 stainless steel as the material and explored various metallurgical methods such as magnetic annealing and the addition of Mo as well as increasing the Si content to investigate the microstructure, mechanical behavior, and magnetic properties of each material, aiming to improve the magnetic properties of 430 stainless steel. Experimental results showed that the four electromagnetic steel materials (430F, 430F-MA, 434, and KM31) had equiaxed grain matrix structures, and excellent tensile and elongation properties were observed for each specimen. Additionally, the magnetic properties of the 430F specimen were similar under the DC and AC-10 Hz conditions. According to the hysteresis curves under different AC frequencies (10, 100, 1000 Hz), both magnetic annealing and the addition of Mo could reduce the Bm, Br, and Hc values of the raw 430F material. Increasing the Si content resulted in a decrease in Hc values and an increase in Bm and Br values.

Investigating the Role of CNP and CNP Aggregates in the Rheological Breakdown of Triglyceride Systems

In many food applications, the mechanical properties of fats play a critical role in determining the processing performance of fat-rich products. In fact, fat crystal networks form a particular class of soft materials that exhibit viscoelastic properties. The uniqueness of the mechanical response is intricately linked to the hierarchical nature of the system, as fats possess a complex architecture encompassing features at different scale levels (i.e., length scales). Since the discovery of crystalline nanoplatelets (CNPs), it has been hypothesized that CNPs are the basic building blocks of lipid networks and that CNPs are the responsible units for the mechanical properties of fats. This hypothesis, however, has only been partially tested. In this article, we examine which units could be responsible (e.g., lamellae, CNP, CNP aggregates) for the mechanical breakdown of fat crystal networks, through Rheo-USAXS in beamline ID02 (ESRF, Grenoble, France). Time-resolved USAXS profiles were acquired during the three steps of a three-interval thixotropy test (3iTT), namely, pre-shear, shear and recovery. The results were then utilized to evidence which specific length scale is arranged (i.e., orientated) during rheological breakdown. The findings suggest that, at the tested shear rates, orientation is only visible from 250 nm onwards, suggesting that the rheological breakdown of triglycerides is primarily driven by the orientation, and possible disruption, of CNP aggregates. These results reveal the critical role of CNP aggregates in the mechanical properties of fats. In the longer term, we believe this study will steer future research toward a more focused understanding of CNP aggregation and disaggregation dynamics.

An Octopus-Inspired Stimulus-Responsive Structural Color Hydrogel for Uterus Cervical Canal Stent.

Soft-bodied aquatic organisms have exhibited remarkable capabilities in navigating and moving within liquid environments serving as a profound inspiration for the development of bionic robots with intricate movements. Traditional rigid components are being replaced by stimulus-responsive soft materials such as hydrogels and shape memory polymers, leading to the creation of dynamically responsive soft robots. In this study, the development of a bionic robot inspired by the shape of an octopus and the adsorptive properties of its tentacles, specifically tailored for targeted stimulation and pH sensing in the cervix, are presented. This approach involves the design of a soft, water-based Janus adhesive hydrogel patch that adheres to specific parts of the cervix and responds to pH changes through external stimuli. The hydrogel patch incorporates inverse opal microstructures mimicking the legs of an octopus, to facilitate efficient and stable locomotion, unidirectional transport of biofluids, and pH-responsive behavior. This miniature bionic robot showcases controlled adhesion and precise unidirectional fluid transport highlighting its potential for targeted stimulus response and pH sensing in the uterine cervical tract. This breakthrough opens new avenues for medical applications within the expanding field of soft-bodied robotics.

A unique Fe-based soft magnetic alloy and its magnetic softening mechanism

Fe-based amorphous alloys with good glass-forming ability (GFA), superior soft magnetic properties, low cost, and a wide heat treatment window have long been pursued in the field of soft magnetic materials due to their importance for mass production and broad applications. In the present study, by strategically adjusting the composition of a low-cost Fe-Si-B-P-Cu-C alloy, we achieved a saturation magnetization (Ms) of approximately 186 emu/g and a coercivity (Hc) of about 6 A/m for the Fe82.5 alloy with a good GFA. Specifically, the limited Cu content and suitable contents of metalloid elements played pivotal roles in enhancing the nuclei barrier and stabilizing the amorphous matrix. This, in turn, facilitated the formation of a finely uniform nanocrystalline structure dispersed within the amorphous matrix, enhancing soft magnetic properties during annealing. Notably, this magnetic softening behavior occurred at a lower heating rate. Structural characterizations revealed that a transient metalloid-rich shell and a stable amorphous matrix contributed to the slow growth of the α-Fe (Si) during prolonged isothermal annealing. This is in contrast to the agglomeration of small nanograins into larger clusters at high heating rates, which enhances the versatility and potential applicability of the alloy. The successful development of this novel nanocrystalline alloy offers promising guidance for addressing the challenges associated with the mass production of soft magnetic materials.

Viscoelasticity in 3D Cell Culture and Regenerative Medicine: Measurement Techniques and Biological Relevance.

The field of mechanobiology is gaining prominence due to recent findings that show cells sense and respond to the mechanical properties of their environment through a process called mechanotransduction. The mechanical properties of cells, cell organelles, and the extracellular matrix are understood to be viscoelastic. Various technologies have been researched and developed for measuring the viscoelasticity of biological materials, which may provide insight into both the cellular mechanisms and the biological functions of mechanotransduction. Here, we explain the concept of viscoelasticity and introduce the major techniques that have been used to measure the viscoelasticity of various soft materials in different length- and timescale frames. The topology of the material undergoing testing, the geometry of the probe, the magnitude of the exerted stress, and the resulting deformation should be carefully considered to choose a proper technique for each application. Lastly, we discuss several applications of viscoelasticity in 3D cell culture and tissue models for regenerative medicine, including organoids, organ-on-a-chip systems, engineered tissue constructs, and tunable viscoelastic hydrogels for 3D bioprinting and cell-based therapies.

Strain to shine: stretching-induced three-dimensional symmetries in nanoparticle-assembled photonic crystals

Stretching elastic materials containing nanoparticle lattices is common in research and industrial settings, yet our knowledge of the deformation process remains limited. Understanding how such lattices reconfigure is critically important, as changes in microstructure lead to significant alterations in their performance. This understanding has been extremely difficult to achieve due to a lack of fundamental rules governing the rearrangements. Our study elucidates the physical processes and underlying mechanisms of three-dimensional lattice transformations in a polymeric photonic crystal from 0% to over 200% strain during uniaxial stretching. Corroborated by comprehensive experimental characterizations, we present analytical models that precisely predict both the three-dimensional lattice structures and the macroscale deformations throughout the stretching process. These models reveal how the nanoparticle lattice and matrix polymer jointly determine the resultant structures, which breaks the original structural symmetry and profoundly changes the dispersion of photonic bandgaps. Stretching induces shifting of the main pseudogap structure out from the 1st Brillouin zone and the merging of different symmetry points. Evolutions of multiple photonic bandgaps reveal potential optical singularities shifting with strain. This work sets a new benchmark for the reconfiguration of soft material structures and may lay the groundwork for the study of stretchable three-dimensional topological photonic crystals.

Dynamic modeling and analysis of viscoelastic hard-magnetic soft actuators with thermal effects

Hard-magnetic soft materials (HMSMs) are a class of magnetoactive smart polymers capable of sustaining a high residual magnetic flux density and can undergo large actuation strains under an external magnetic excitation. Due to these exceptional characteristics, soft actuators based on HMSMs hold enormous potential for remote-controlled applications. The temperature and viscoelasticity considerably influence the performance of these materials during the operation. This work aims to develop an analytical framework for modeling the dynamic behavior of a planar hard-magnetic soft actuators (HMSA) considering temperature and viscoelastic effects. The constitutive behavior of the viscoelastic HMSA is described by employing an incompressible neo-Hookean model in conjunction with a Zener rheological model and the Rayleigh dissipation function. The dynamic governing differential equations of motion are derived by utilizing the non-conservative form of the Euler–Lagrange equation. This study delves into the collective influence of temperature and viscoelastic properties on the stability, periodicity, and resonance characteristics of nonlinear vibrations exhibited by HMSM-based planar actuator subjected to dynamic magnetic loading, presenting the findings through time-history responses, Poincaré maps, and phase-plane plots. The presented results can help in the efficient and robust design of HMSM-based actuators and can also serve as an initial step toward the development of advanced actuators exposed to dynamic loading under variable temperatures for diverse applications in the fields of engineering and medicine.

Photochromic ionogel with a wide temperature range and fatigue resistance for high-resolution rewritable information record

Recently, photochromic hydrogels have received significant attention and hold substantial promise for rewritable information record. However, the intrinsic instability of hydrogels has restricted their applications. Herein, a photochromic ionogel aiming at extending service life for long-term use is presented by embedding photochromic ammonium molybdate tetrahydrate [(NH4)6Mo7O24·4H2O] (Mo7) in engineered double networks. Covalently cross-linked 2-hydroxyethyl acrylate (HEA) and self-assembled cationic cellulose (JR-400) constitute the networks, and a protic ionic liquid of ethylammonium nitrate (EAN) is immobilized therein. Such a design affords the ionogel comprehensive properties, including high optical transparency (>97%), good adhesion, anti-dehydration, wide operating temperature range (–60 to 150 °C) as well as the sensitive and stable UV-light responsiveness (within 30 s). Besides, the ionogel exhibits admirable mechanical properties of high toughness (over 180 kJ/m3), excellent resilience and a high fatigue threshold (over 1000 cycles with negligible hysteresis). The photochromic process is typically accomplished by photoreduction of Mo7, which is combined with network through electrostatic interaction with quaternized JR-400. The distinctive feature is that EAN serving as both proton donor and electron donor, plays a dominant role in coloration process and formation of charge-transfer complex. The photochromic mechanism which is less well understood in ionic liquid medium, has been revealed. Remarkably, the ionogel used as an information carrier exhibits outstanding stability in a wide operating temperature range. The superiorities of the photochromic ionogel including accurate information recording capacity and application in harsh environments have greatly boosted the high-quality information dissemination and expanded applications of photochromic soft materials.

Thermo-osmosis of a near-critical binary fluid mixture: A general formulation and universal flow direction.

We consider a binary fluid mixture, which lies in the one-phase region near the demixing critical point, and study its transport through a capillary tube linking two large reservoirs. We assume that short-range interactions cause preferential adsorption of one component onto the tube's wall. The adsorption layer can become much thicker than the molecular size, which enables us to apply hydrodynamics based on a coarse-grained free-energy functional. For transport processes induced by gradients of the pressure, composition, and temperature along a cylindrical tube, we obtain the formulas of the Onsager coefficients to extend our previous results on isothermal transport, assuming the critical composition in the middle of each reservoir in the reference equilibrium state. Among the processes, we focus on thermo-osmosis-mass flow due to a temperature gradient. We explicitly derive a formula for the thermal force density, which is nonvanishing in the adsorption layer and causes thermo-osmosis. This formula for a near-critical binary fluid mixture is an extension of the conventional formula for a one-component fluid, expressed in terms of local excess enthalpy. We predict that the direction of thermo-osmotic flow of a mixture near the upper (lower) consolute point is the same as (opposite to) that of the temperature gradient, irrespective of which component is adsorbed on the wall. Our procedure would also be applied to dynamics of a soft material, whose mesoscopic inhomogeneity can be described by a coarse-grained free-energy functional.

Physics-informed data-driven discovery of constitutive models with application to strain-rate-sensitive soft materials

AbstractA novel data-driven constitutive modeling approach is proposed, which combines the physics-informed nature of modeling based on continuum thermodynamics with the benefits of machine learning. This approach is demonstrated on strain-rate-sensitive soft materials. This model is based on the viscous dissipation-based visco-hyperelasticity framework where the total stress is decomposed into volumetric, isochoric hyperelastic, and isochoric viscous overstress contributions. It is shown that each of these stress components can be written as linear combinations of the components of an irreducible integrity basis. Three Gaussian process regression-based surrogate models are trained (one per stress component) between principal invariants of strain and strain rate tensors and the corresponding coefficients of the integrity basis components. It is demonstrated that this type of model construction enforces key physics-based constraints on the predicted responses: the second law of thermodynamics, the principles of local action and determinism, objectivity, the balance of angular momentum, an assumed reference state, isotropy, and limited memory. The three surrogate models that constitute our constitutive model are evaluated by training them on small-size numerically generated data sets corresponding to a single deformation mode and then analyzing their predictions over a much wider testing regime comprising multiple deformation modes. Our physics-informed data-driven constitutive model predictions are compared with the corresponding predictions of classical continuum thermodynamics-based and purely data-driven models. It is shown that our surrogate models can reasonably capture the stress–strain-strain rate responses in both training and testing regimes and improve prediction accuracy, generalizability to multiple deformation modes, and compatibility with limited data.