Rheologica Acta最新文献

{"title":"A century later: a bearing-capacity framework to extract Mohr-Coulomb parameters from penetration tests","authors":"C. Maximilian Hechtl,&nbsp;Stefan Segl,&nbsp;Thomas Kränkel,&nbsp;Christoph Gehlen","doi":"10.1007/s00397-026-01562-x","DOIUrl":"10.1007/s00397-026-01562-x","url":null,"abstract":"<div>\u0000 \u0000 <p>This study reformulates classical bearing-capacity theory into a depth-resolved framework for extracting apparent Mohr–Coulomb parameters from quasi-static flat-punch penetration tests. The measured force–depth response is converted to the mean contact stress <span>(varvec{q(z)})</span> and analysed as a function of depth, with cohesive, surcharge, and unit-weight contributions. Under homogeneous, axisymmetric conditions, the internal friction angle <span>(varvec{varphi })</span> and cohesion <span>(varvec{c})</span> are obtained from the slope and intercept of the quasi-steady <span>(varvec{q(z)})</span> relation. Applied to an inert montmorillonite–glycerin reference material, the method yielded reproducible results across punch diameters <span>(varvec{D=20})</span>–<span>(varvec{40~textrm{mm}})</span>, giving <span>(varvec{varphi _{pen}approx 4.8^circ })</span> and <span>(varvec{c_{pen}approx 0.85~textrm{kPa}})</span>. Independent vane tests gave <span>(varvec{c_{textrm{vane}}approx 0.70~textrm{kPa}})</span>, and direct shear box tests yielded <span>(varvec{varphi _{textrm{dsb}}approx 4.45^circ })</span> and <span>(varvec{c_{textrm{dsb}}approx 1.16~textrm{kPa}})</span>. The friction angles from penetration and DSB testing were consistent, while the cohesion values differed in the ordering expected from their respective interface and deformation conditions. Within the quasi-static, low-stress regime examined here, the penetration-based approach provides an efficient method for quantifying apparent Mohr–Coulomb parameters of soft cohesive–frictional materials.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"475 - 486"},"PeriodicalIF":3.0,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01562-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slip-link model predictions for the flow of entangled melts of star-branched and linear chains of similar span length","authors":"Maria Katzarova,&nbsp;Andrés Córdoba,&nbsp;Diego Becerra,&nbsp;Jay D. Schieber","doi":"10.1007/s00397-026-01560-z","DOIUrl":"10.1007/s00397-026-01560-z","url":null,"abstract":"<p>The nonlinear rheology of entangled polymers is strongly influenced by molecular architecture, yet architectural complexity does not necessarily translate into superior processing performance. Here, we investigate the transient shear and uniaxial elongation responses of symmetric star-branched and linear polystyrene chains of similar span length, using recent experimental data of Liu et al. (2025). Predictions are performed with the clustered fixed slip-link model (CFSM), a coarse-grained implementation of the discrete slip-link model, recently revised to accurately describe the mean-field constraint dynamics in star-branched polymers (Katzarova et al. Macromolecules, 59(1):564–574 2026). The model quantitatively reproduces the transient shear response for both architectures at moderately large Rouse-Weissenberg numbers (<span>(Wi_textrm{R}lesssim 2)</span>) and captures elongational stress growth up to Hencky strains of approximately two, achieving a level of agreement with experiment that is unprecedented for coarse-grained models in these nonlinear regimes. Consistent with prior experimental interpretations, we confirm theoretically that the Rouse-stretch time of symmetric star polymers can be estimated in the same manner as for linear chains, provided the span length is taken as twice the arm molecular weight. The results further suggest that, far-from-equilibrium, branch-point diffusion in star polymers plays a diminished role in the nonlinear response, highlighting an architectural effect relevant to polymer processing flows.</p>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"409 - 418"},"PeriodicalIF":3.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rate-dependent relaxation time and viscoelastic properties of a silicone-based 3D printing material","authors":"Muhanna A. H Alrashdi,&nbsp;Valeria Diamanti,&nbsp;Hamada Elsayed,&nbsp;Giulio G. Giusteri","doi":"10.1007/s00397-026-01559-6","DOIUrl":"10.1007/s00397-026-01559-6","url":null,"abstract":"<p>We measure the rheological properties of a newly formulated silicone-based ink for additive manufacturing technologies. The basic measurement for such viscoelastic non-Newtonian fluids, namely small amplitude oscillatory shear (SAOS) highlights the need to consider a relaxation time of the polymeric microstructure that depends smoothly on the oscillation frequency. We incorporate this information within a recently developed framework for the tensorial description of viscoealastic fluids. With this, we can achieve a significant improvement in the fitting of the experimental data. Moreover, we can extrapolate the frequency dependence of the relaxation time to its rate dependence in steady shear flows, leading to a prediction of both the viscosity and the first normal stress coefficient which is in good agreement with experiments. This provides a new way to connect the linear viscoelastic response to the nonlinear response of the material.</p>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"487 - 494"},"PeriodicalIF":3.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous rheo-Raman characterization of crosslinking and crystallization in semi-crystalline Diels–Alder polymer networks","authors":"Jelle De Ceulaer,&nbsp;Ruth Cardinaels,&nbsp;Peter Van Puyvelde","doi":"10.1007/s00397-026-01558-7","DOIUrl":"10.1007/s00397-026-01558-7","url":null,"abstract":"<p>Dynamic covalent networks (DCNs) based on the thermoreversible Diels–Alder (DA) reaction offer a unique combination of reprocessability, recyclability, and tunable mechanical properties. When dynamic bonds are introduced on semi-crystalline polymers such as poly(<span>(varepsilon)</span>-caprolactone) (PCL), their solidification is governed by the interplay of the chemical crosslinking reaction and the physical crystallization. However, conventional characterization techniques typically probe these mechanisms separately on distinct samples, whereas both mechanisms are convoluted in the rheological response. This makes it difficult to disentangle their simultaneous effects under processing-relevant conditions. Therefore, a hyphenated rheo-Raman technique is proposed that enables the <i>in situ</i> and simultaneous monitoring and correlation of both macroscopic rheological properties and microscopic molecular-level transformations during DA network formation and PCL crystallization. Isothermal experiments reveal an excellent agreement between Raman-derived and rheological gelation, confirming the reliability of spectroscopic tracking for dynamic network formation. Crystallization studies reveal that pre-existing crosslinks slow down crystallization. However, the Raman spot size highlights spatial restrictions arising from spherulitic growth and nucleation density, which can cause delays in local crystallinity tracking relative to bulk crystallization. Additionally, non-isothermal cooling experiments demonstrate how thermal history and cooling rate dictate the relative progression of crystallization and DA crosslinking. Together, these findings establish rheo-Raman spectroscopy as a powerful technique to decouple and quantify complex and interacting solidification pathways in semi-crystalline DCNs. The resulting insights provide a new experimental foundation to tailor improved structure–property relationships in dynamic covalent networks, with direct relevance to advanced processing methods such as additive manufacturing.</p>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"441 - 456"},"PeriodicalIF":3.0,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Multi-variable implicit viscosity model for shear-thinning fluids","authors":"Mohammad Amin Ghorbani,&nbsp;Mohammad Pourhosseinian,&nbsp;Florian Arthofer,&nbsp;Silke Koch,&nbsp;Christian Marschik,&nbsp;Daniela Misul,&nbsp;Bahram Haddadi","doi":"10.1007/s00397-026-01564-9","DOIUrl":"10.1007/s00397-026-01564-9","url":null,"abstract":"","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 4","pages":"337 - 339"},"PeriodicalIF":3.0,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01564-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying the influence of temperature and water-to-cement ratio on cement paste rheological properties","authors":"Amalia Ioannou,&nbsp;Pavlos S. Stephanou","doi":"10.1007/s00397-026-01557-8","DOIUrl":"10.1007/s00397-026-01557-8","url":null,"abstract":"<div>\u0000 \u0000 <p>The rheological behavior of cement pastes is highly affected by temperature and water content, which hinders our capacity to build effectively in extreme conditions. We herein employ a recently proposed constitutive rheological model (Ioannou and Stephanou, J Rheol 67:849–861, 2023), to model the rheological behavior of cement pastes over an extensive temperature and water-to-cement ratio (w/c) range. We thoroughly parametrize the model for both fresh and aged cement pastes to accommodate quantitative predictions against available literature rheological data. Our work is the first to provide reliable rheological predictions for cement pastes at various w/c ratios and temperatures. Furthermore, it employs one of very few models that can predict normal stresses, whose importance in pumping and extrusion is today only partially understood. The model is expected to be utilized in the future for modeling mortar and concrete, as well as to simulate actual flowing processes occurring in construction sites.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"457 - 474"},"PeriodicalIF":3.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01557-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear and elongational rheology of recycled polypropylene-based multilayer barrier films: impact of thermomechanical reprocessing","authors":"Hissein Bechibo Adam,&nbsp;Mohamed Yousfi,&nbsp;Abderrahim Maazouz,&nbsp;Khalid Lamnawar","doi":"10.1007/s00397-026-01561-y","DOIUrl":"10.1007/s00397-026-01561-y","url":null,"abstract":"<div>\u0000 \u0000 <p>The present work investigates the impact of successive thermomechanical recycling cycles on the shear and elongation rheological properties of flexible multilayer barrier films. The main objective is to use these rheological properties as indicators to probe recycling-induced structural modifications in model multilayer films composed of polypropylene (88 wt%), ethylene–vinyl alcohol (7 wt%) as the barrier layer, and maleic anhydride-grafted polypropylene (5 wt%) as the compatibilizing tie layer. On one hand, small-amplitude oscillatory shear (SAOS) measurements reveal variations in the viscoelastic properties of the multilayer film: complex viscosity decreases up to the second recycling cycle due to PP β-scission, increases in the third recycling cycle likely due to chain crosslinking and copolymer formation between EVOH and PP-g-MA. Beyond the third cycle, a further decrease in viscosity was recorded, which may be associated with weakened interfacial adhesion and the coalescence of EVOH domains within the PP matrix. These results were further supported by morphological observations using SEM and by FTIR spectroscopy analyses. On the other hand, uniaxial extensional rheology, revealed a strong sensitivity to the competing effects of PP degradation and EVOH crosslinking. Despite the strain-softening behavior of the individual constituents, a pronounced strain-hardening response develops after multiple reprocessing cycles. Interestingly, modelling of the interfacial stress contribution highlights its decrease with increasing recycling cycles. The interfacial stress is initially higher in the multilayer film due to interface/interphase continuity and chain entanglements but progressively reduced by thermomechanical processing, owing to interfacial discontinuity and nodular morphology development in the recycled multilayers systems.</p>\u0000 <span>AbstractSection</span>\u0000 Graphical Abstract\u0000 <div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div>\u0000 \u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 5","pages":"419 - 440"},"PeriodicalIF":3.0,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147727569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscosity functions of shear flows for fractional Jeffreys fluids","authors":"Rattanaporn Promjariyakoon,&nbsp;Pongthep Poungthong,&nbsp;Chanyut Kolitawong,&nbsp;Alan J. Giacomin","doi":"10.1007/s00397-026-01551-0","DOIUrl":"10.1007/s00397-026-01551-0","url":null,"abstract":"<div>\u0000 \u0000 <p>In our previous work (Promjariyakoon 2025; Promjariyakoon et al. 2026), we derive exact analytical solutions for (1) steady shear viscosity, and (2) shear stress growth rheological responses of the fractional Maxwell fluid (FMF) generalized to tensor form. By <i>shear stress growth</i>, we mean the sudden inception of steady shear flow. We found good agreement with experimental observation, though this left some room for improvement. In this work, following our previous method, we improve upon the FMF by adding one more fractional derivative for retardation to get the fractional Jeffreys model (FJM), a fractional Kelvin-Voigt model arranged in series with a spring-pot. We determine (1) complex viscosity, (2) the shear stress growth viscosity function, (3) then extend these to the steady shear viscosity between the stress and the local properties of theusing Gleissle mirror relations, and (4) shear stress relaxation following cessation of steady shear flow. Our FJM exact solution improves significantly upon the FMF, agreeing well with available measurements on aqueous xanthan gum solutions, so long as the initial residual stresses in the sample are accounted for. We show that its material functions are experimentally measurable and physically interpretable quantities. Finally, we construct temperature master curves for a low-density polyethylene melt. We do so to generalize predictions of viscosity under varying temperatures. Our worked example illustrates how to use our main results.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 4","pages":"389 - 408"},"PeriodicalIF":3.0,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suspension stability of a magnetorheological fluid employing high viscosity linear polysiloxane carrier fluids: a three-year study","authors":"Young T. Choi,&nbsp;Norman M. Wereley","doi":"10.1007/s00397-026-01555-w","DOIUrl":"10.1007/s00397-026-01555-w","url":null,"abstract":"<div><p>This study investigates the long-term sedimentation stability of high-viscosity linear polysiloxane-based magnetorheological fluids (HVLP MRFs) using an automated vertical-axis inductance monitoring system (AVAIMS). While the inverse relationship between carrier fluid viscosity and sedimentation rate is theoretically established through Stokes’ law, experimental validation over multi-year timescales remains unreported, and no systematic framework exists for quantifying the relative contributions of formulation parameters to multi-boundary sedimentation stability. This work addresses this gap by tracking the sedimentation behavior of three HVLP MRF samples over an unprecedented 1095 days. Variables include particle loading (35 vol% and 45 vol%) and carrier fluid viscosity (5,000 cSt and 10,000 cSt), with a commercial MRF (LORD Corp., MRF-140CG) serving as a benchmark. The AVAIMS enables detailed characterization of three sedimentation boundaries—the mud-line, gel-line, and cake-line—extending beyond conventional mud-line tracking. The HVLP MRF with 45 vol% particle loading and 10,000 cSt carrier fluid maintained 78.0% of its original concentration zone after 1095 days, whereas the LORD MRF-140CG underwent complete stratification by day 267. Building upon this qualitative characterization, a quantitative framework was developed comprising normalized sensitivity coefficients and a novel Comprehensive Stability Index (CSI) that integrates all boundary measurements into a single metric. This analysis reveals that particle loading is approximately four times more effective than carrier fluid viscosity in achieving multi-boundary sedimentation stability, providing actionable guidelines for formulation optimization.</p></div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 3","pages":"287 - 302"},"PeriodicalIF":3.0,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01555-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147558759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-variable implicit viscosity model for shear-thinning fluids","authors":"Mohammad Amin Ghorbani,&nbsp;Mohammad Pourhosseinian,&nbsp;Florian Arthofer,&nbsp;Silke Koch,&nbsp;Christian Marschik,&nbsp;Daniela Misul,&nbsp;Bahram Haddadi","doi":"10.1007/s00397-026-01556-9","DOIUrl":"10.1007/s00397-026-01556-9","url":null,"abstract":"<div>\u0000 \u0000 <p>Accurately modeling the viscosity of shear-thinning elastomer compounds is crucial for optimizing their performance in industrial applications. Classical models (Power Law, Carreau, Cross) cannot directly account for temperature, and when coupled with temperature models (Arrhenius, WLF, VTF), they become mathematically complex and computationally costly for simulations. This study introduces the Multi-Variable Implicit (MVI) viscosity model, derived using machine learning-based symbolic regression. It offers a simplified mathematical structure while maintaining high predictive accuracy. The MVI model implicitly incorporates both shear-rate and temperature dependence in a single expression, while also capturing zero-shear viscosity through a Newtonian plateau. This feature ensures numerical stability and yields physically meaningful results across a wide range of shear rates and temperatures. The model was trained on high pressure capillary-rheometer data of an elastomer (70–120 °C; 10-5000 <i>1/s</i>), corrected for entrance losses and non-Newtonian profiles, and extended with synthetic points from a Carreau-Arrhenius fit to include the low-shear plateau. On test data, MVI achieved R² = 0.99 while preserving finite zero-shear viscosity. Independent validation on different materials across wider ranges gave R² = 0.957–0.990 without retraining, confirming strong generalization. To demonstrate its practical applicability, capillary-flow CFD simulations were carried out using both the MVI and Carreau-Arrhenius models. While each gave accurate predictions of the pressure-flow response, the MVI model required less computational effort because it avoids repeated exponential calculations. These findings highlight the MVI model as a novel, efficient, and practical solution for viscosity modeling in polymer processing and other fluid flow applications.</p>\u0000 </div>","PeriodicalId":755,"journal":{"name":"Rheologica Acta","volume":"65 4","pages":"317 - 335"},"PeriodicalIF":3.0,"publicationDate":"2026-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00397-026-01556-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147588404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}