Stress Fluid Research Articles

Characterization and mechanism of multi-scale pore changes in scCO2-water injection into different porosity coal specimen

The process of supercritical CO2 (scCO2) injection into the coal body induces inhomogeneous changes in pore, which has a significant effect mechanical changes of the geological storage of CO2 coal seams. In this study, the effect of scCO2-water intrusion on coal samples with different porosity was investigated by NMR equipment and the change in the mechanical properties were tested by uniaxial compression and acoustic emission techniques after treatment. Results showed that during the treatment of scCO2-water, the pores of different scales showed an exponential change trend of y = a·xb, with the macropore of low-porosity coal samples continuously increasing and the macropore of high-porosity coal samples continuously decreasing. The pore changes after treatment mainly occurred in the micropore range, and the changes of low-porosity coal samples were more than 6%, while the changes of high-porosity coal samples were less than 2.3%. The changes in the fractal dimension of low-porosity coal samples exceeded those observed in high-porosity. The geochemical impact, effective stress of scCO2-water mixed fluid, and the adsorption and expansion mechanism of matrix macromolecules are influenced by varying porosity. This study helps to understand the internal multi-scale pore coupling mechanism and the effect on the coal mechanical properties after CO2 injection.

Synthesis of rGO/CoFe2O4 Composite and Its Magnetorheological Characteristics.

In this study, composite particles of rGO/CoFe2O4 were synthesized using a solvothermal method to fabricate a low-density magnetorheological (MR) material with enhanced sedimentation stability. The morphology and crystallographic features of rGO/CoFe2O4 were characterized via SEM, TEM, and XRD, and its magnetic properties were tested using VSM. The MR fluid was formulated by blending rGO/CoFe2O4 particles into silicone oil. Under different magnet strengths (H), a rotational rheometer was used to test its MR properties. Typical MR properties were observed, including shear stress, viscosity, storage/loss modulus, and dynamic yield stress (τdy) following the Herschel-Bulkley model reaching 200 Pa when H is 342 kA/m. Furthermore, the yield stress of the MR fluid follows a power law relation as H increases and the index changes from 2.0 (in the low H region) to 1.5 (in the high H region). Finally, its MR efficiency was calculated to be about 104% at H of 342 kA/m.

Experimental Investigation of the Effect of Fault Reactivation Induced by Water Injection

An understanding of fault reactivation induced by water injection is of great significance for geothermal energy development and utilization. We conducted a series of water injection shear tests on low-permeability granite samples that each contained a single saw-cut fault under locally undrained conditions. Slip characteristics were analyzed by varying the fluid pressurization rate, confining pressure, and stress state of the fault to understand fault reactivation. The experimental results demonstrated that at a high pressurization rate, a higher local fluid pressure was needed to reactivate the fault than had been estimated theoretically, and the required fluid pressure increased with an increase in pressurization rate. The fluid pressurization rate and confining pressure both controlled the slip mode of the fault. The slip mode changed from dynamic slip to quasi-static slip at a high pressurization rate, and the peak slip rate of dynamic slip increased with an increasing pressurization rate. The fault showed significant stick-slip characteristics under a high confining pressure, as fault locking and reactivation phenomena occurred repeatedly. Faults with different initial stress states had little influence on the slip mode after the onset of slip.

A new ER valve composed of multilayer mesh electrodes

In many cases, ER valves are required to be used at lower operating voltages. For example, to develop a two-dimensional Braille matrix display, it is necessary to lay out many ER valves and control each Braille dot independently. If the commonly used parallel plate electrodes are applied, a low voltage can only be used when the electrode gap is very small, which will make the ER valve flow resistance very large, thus making it difficult to achieve effective control. A new type of ER valve composed of multilayer mesh electrodes was designed, which are arranged vertically in the direction of ER fluid flow. The flow rate of the ER valve is determined by the opening ratio of the mesh electrodes. This type of mesh electrode results in a more complex electric field distribution, which has a different action pattern on ER fluid yield stress compared to parallel electrodes. The non-uniform electric field generated by mesh electrodes under different operating voltages was simulated using COMSOL software, and the pressure drops of ER valves with various sizes of mesh electrodes under different voltages were experimentally investigated. The results indicate that the longitudinal electric field component plays a dominant role, and the stress of the ER fluid exhibits a periodic and gradient distribution. This valve exhibits good ER performance when the applied voltage is much lower than that of parallel electrodes. At the same time, the flow rate of the ER valve can be increased by enlarging the opening ratio of the mesh electrodes. Even if the applied voltage is 180 V, the pressure drop of the ER valve is large enough and the operation stability is good. This new type of ER valve makes the device small in size, easy to control intelligently and low cost. Multilayer mesh electrodes also have universal application value in ER technology.

Study on the tribological and rheological properties of magnetorheological fluids based on different base oils

Abstract Base oil has great influence on the tribological and rheological properties of magnetorheological fluid. In this paper, four types of magnetorheological fluid are prepared respectively by silicone oil, mineral oil, synthetic oil (PAO) and castor oil, and their tribological and rheological properties are investigated. Firstly, the viscosity of the magnetorheological fluid is measured by a viscometer. Then the friction coefficient and wear scar diameter of the magnetorheological fluid is measured by a four ball friction testing machine. Next, the sedimentation rate of the magnetorheological fluids is calculated by the observation method. Finally, the shear yield stress of the magnetorheological fluid is measured by a rheometer. By analyzing the experimental data, it is concluded that the magnetorheological fluid prepared by white mineral oil and castor oil has excellent wear resistance. The magnetorheological fluid prepared by castor oil has better sedimentation stability and higher shear yield stress. Consequently, the magnetorheological fluid prepared by castor oil has better comprehensive properties.

Path and Slip Dependent Behavior of Shallow Subduction Shear Zones During Fluid Overpressure

AbstractElevated pore fluid pressure is proposed to contribute to slow earthquakes along shallow subduction plate boundaries. However, the processes that create high fluid pressure, disequilibrium compaction and dehydration reactions, lead to different effective stress paths in fault rocks. These paths are predicted by granular mechanics frameworks to lead to different strengths and deformation modes, yet granular mechanics do not predict their effects on fault stability. To evaluate the role of fluid overpressure on shallow megathrust strength and slip behavior, we conducted triaxial shear experiments on chlorite and celadonite rich gouge layers. Experiments were conducted at constant temperature (130 and 100°C), confining pressure (130 and 140 MPa), and pore fluid pressures (between 10 and 120 MPa). Fluid overpressure due to disequilibrium compaction was simulated by increasing confining and pore fluid pressure synchronously without exceeding the target effective pressure, whereas overpressure due to dehydration reactions was simulated by first loading the sample to a target isotropic effective pressure and then increasing pore fluid pressure to reduce the effective pressure. We find that the effects of fluid pressure and stress path on the mechanical behavior of the chlorite and celadonite gouges can generally be described using the critical state soil mechanics (CSSM) framework. However, path effects are more pronounced and persist to greater displacements in chlorite because its microstructure is more influenced by stress path. Due to its effects on microstructure, the stress path also imparts greater control on the rate‐dependence of chlorite strength, which is not predicted by CSSM.

#16. Variable fluid stresses may alter breast cancer expression in a 3D perfusion model of bone metastasis

#16. Variable fluid stresses may alter breast cancer expression in a 3D perfusion model of bone metastasis

Term Neonate Born With Right Upper Extremity Skin Necrosis at Birth: A Case Report.

Congenital skin and soft tissue necrosis is a rare condition associated with significant morbidity and mortality in neonates. The authors treated a neonate born with significant skin necrosis of the right forearm. The case report is followed by a literature review and discussion of previously published reports of neonatal skin necrosis. A term female neonate was admitted to our hospital at 24 h of age for skin necrosis of the right forearm with sloughing and edema below the right elbow and contractures of her fingers. Topical treatment with cleansing and antibiotic application was initiated. The LUNA florescent microangiography showed superficial perfusion defects in the arm and dorsum of the hand along with overt ischemia over the dorsal aspect of the forearm. She was treated with intravenous antibiotics following a sepsis evaluation. Subsequently, she developed hypotension treated with fluid boluses, dopamine, and stress dose steroids. Concerns of wound infection and sepsis led to debridement of the necrotic area within the first 24 h post-admission. Wet-to-dry dressing changes using Vashe wound solution were begun postoperatively.; followed by placement of Integra on postoperative day-of-life (DOL) 7; dressing takedown on DOL 12; and autografting of the right hand and forearm with disarticulation of the 4th distal interphalangeal joints and right 5th distal interphalangeal transection on DOL 24. Postoperative dressing care was continued during the remainder of the hospital stay, she remained stable without any further complications and was discharged home on DOL 34 with outpatient clinic follow-up.

Incorporating Unresolved Stresses in Blood Damage Modeling: Energy Dissipation More Accurate Than Reynolds Stress Formulation.

Reynolds Averaged Navier Stokes (RANS) models are often used as the basis for modeling blood damage in turbulent flows. To predict blood damage by turbulence stresses that are not resolved in RANS, a stress formulation that represents the corresponding scales is required. Here, we compare two commonly employed stress formulations: a scalar stress representation that uses Reynolds stresses as a surrogate for unresolved fluid stresses, and an effective stress formulation based on energy dissipation. We conducted unsteady RANS simulations of the CentriMag blood pump with three different closure models and a Large Eddy Simulation (LES) for reference. We implemented both stress representations in all models and compared the resulting total stress distributions in Eulerian and Lagrangian frameworks. The Reynolds-stress-based approach overestimated the contribution of unresolved stresses in RANS, with differences between closure models of up to several orders of magnitude. With the dissipation-based approach, the total stresses predicted with RANS deviated by about 50% from the LES reference, which was more accurate than only considering resolved stresses. The Reynolds-stress-based formulation proved unreliable for estimating scalar stresses in our RANS simulations, while the dissipation-based approach provided an accuracy improvement over simply neglecting unresolved stresses. Our results suggest that dissipation-based inclusion of unresolved stresses should be the preferred choice for blood damage modeling in RANS.

Urethral obstruction in a Brazilian Shorthair cat

The objective of this study was to report a case of urethral obstruction in a neutered, three-year-old male Brazilian Shorthair cat. Urethral obstruction is a frequent and urgent urological issue encountered in veterinary clinics, typically affecting male cats due to the anatomical structure of their long and narrow urethra. This condition can be triggered by factors such as urethral plugs, urinary stones (uroliths), tumors, or muscle disorders. Certain factors like diet, low fluid intake, stress, obesity, and poor management can elevate the risk for these animals to develop uroliths, which can in turn cause urethral obstruction. Commonly observed clinical symptoms include excessive penis licking, perineuria, painful urination (dysuria), and frequent small urinations (pollakiuria). In this reported case, the cat demonstrated recurrent urinary retention and obstruction. Upon clinical examination, the cat appeared lethargic, dehydrated, and showed normal coloration with significant abdominal tenderness. Its bladder was distended and firm to the touch. The patient was stabilized and underwent a relieving cystocentesis. Following this, the cat was hospitalized and a urethral catheterization was performed to remove the obstruction. However, later in the day, the condition recurred, and a cystotomy was conducted. The study concludes by emphasizing that quick and accurate diagnosis is crucial in minimizing the harmful effects caused by urethral obstruction. Furthermore, decisive and personalized treatment is key to maintaining the animal's quality of life, wellbeing, and overall health.

Unveiling the Role of Mechanical Microenvironment in Hepatocellular Carcinoma: Molecular Mechanisms and Implications for Therapeutic Strategies.

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world and the third leading cause of cancer deaths globally. More than 80% of HCC patients have a background of fibrosis or cirrhosis, which leads to changes in physical factors in tumor microenvironment (TME), such as increased stiffness, solid stress, fluid stresses and structural alterations in the extracellular matrix (ECM). In the past, the focus of cancer research has predominantly been on genetic and biochemical factors in the TME, and the critical role of physical factors has often been overlooked. Recent discoveries suggest these unique physical signals are converted into biochemical signals through a mechanotransduction process that influences the biological behavior of tumor cells and stromal cells. This process facilitates the occurrence and progression of tumors. This review delves into the alterations in the mechanical microenvironment during the progression of liver fibrosis to HCC, the signaling pathways activated by physical signals, and the effects on both tumor and mesenchymal stromal cells. Furthermore, this paper summarizes and discusses the therapeutic options for targeting the mechanical aspects of the TME, offering valuable insights for future research into novel therapeutic avenues against HCC and other solid tumors.

Magnetorheological fluids: A comprehensive review

The magnetorheological (MR) fluids contain magnetic micro-sized iron particles, non-magnetic-based fluid, and some additives in order to mitigate sedimentation and agglomeration. The various carrier fluids used in the preparation of MR fluids are mineral oil, silicon oil, castor oil, soybean oil, kerosene, synthetic oils, honge oil, organic oil, water-based oils, etc. However, for obtaining better vibration control, silicone oil is the most preferred one due to its higher viscosity index, lower friction characteristics, higher flash point, and higher shear strength. The MR fluids have various application areas such as dampers, prosthetic knees, valves, brakes, clutches, finishing processes etc. The dampers containing MR fluids are used in automobile cushioning for enhancing passenger comfort and MR suspensions significantly improve steering stability in vehicles. In case of MR brakes, the braking torque on the rotating disks is controlled using the generated shear stress. The carbonyl iron (CI) particles exhibit better rheological characteristics as compared to electrolytic iron (EI) particles. The use of MR fluids produces stable and natural limb movement in orthoses, lower limb prostheses, and exoskeletons. The MR fluids also prove to be very significant in polishing applications. There are various issues with preparation methods and difficulties in the storage of MR fluids. The problems encountered in the synthesis of MR fluids include sedimentation, agglomeration, in-use thickening, corrosion, erosion, etc. The impact of particle proportion, particle shapes, and size has been influential in evaluating MR characteristics. The viscosity and shear stress of MR fluid have been mitigated at higher values of temperature and even CI particles get oxidized at higher temperatures. The CI particles as compared to EI particles are the majority favourable particles used for dispersing state within the MR fluids due to their higher value of saturation magnetization, more availability, and lesser cost. The small-sized particles led to lower wettability, whereas larger-sized particles accounted for an increased sedimentation rate. The currently available MR fluids cost is still on the higher side and the preparation of economical MR fluid is still a big challenge for the researchers. The MR fluids storage is also a big concern. The future scope of MR fluid may be in heavy industries such as nuclear, shipbuilding, oil and gas, space and aviation, etc. to achieve the desired damping response.

Comprehensive Analysis of Internal Flow Dynamics in Pipeline Systems

This research delves into the intricate flow dynamics within a gas pipeline, leveraging the small perturbation equations to elucidate the flow scenario. Utilizing the Python programming language, the study derives the numerical solutions for the governing equations of the pipeline's flow field. This is achieved through the successive over-relaxation (SOR) iterative method in tandem with the Neumann boundary conditions. The flow dynamics are subsequently visualized and analyzed using streamlined diagrams and Mach number cloud representations, facilitating the identification of stress concentration points on the pipeline's inner wall. Such insights significantly affect the pipeline's optimal design and strategic reinforcement. Beyond its immediate application, the methodology presented herein offers a robust framework for addressing diverse fluid mechanics simulation challenges. Its versatility extends to realms such as automotive contour design, pipeline leakage simulations, and engine compressor configurations. When confronted with the need to dissect fluid flow and stress dynamics, professionals can harness the Python-based SOR iteration code to derive governing fluid equations, enabling a graphical interpretation through streamlined and Mach number cloud diagrams. This study, thus, underscores a pivotal toolset for fluid mechanics challenges across various engineering domains.

A proposal for a constitutive equation fitting methodology for the rheological behavior of drilling fluids at different temperatures and high-pressure conditions

Drilling fluids are complex suspensions of particles with a wide diameter range. While extensive research has explored the rheological behavior of drilling fluids, several limitations still exist. High-pressure and high-temperature (HPHT) conditions encountered in drilling fluids have introduced unique challenges, and only a few studies have attempted to develop a comprehensive equation that addresses both aspects concurrently. This study aims to perform a rheological characterization of a water-based drilling fluid (WBDF) containing xanthan gum under HPHT conditions and propose a constitutive equation to fit rheological data in such conditions. The experiments were conducted using an Anton Paar MCR 702TD rotational rheometer, coupled with a pressure cell. Steady-state flow curves were obtained at three different temperatures (25, 55, and 100 °C) and pressures ranging from 100 to 800 bar. The experimental data were fitted to the power-law model, and the rheological parameters of the model were fitted with variations in temperature and pressure. The fluid exhibited shear-thinning behavior, with the influence of temperature being more predominant than the effect of pressure, however, both variables have a strong relationship. Furthermore, we proposed a methodology to establish an equation capable of predicting the shear stress of the drilling fluid under HPHT conditions. The equation was also compared with different drilling fluids tested on different rheometers. This equation demonstrated excellent predictive accuracy within the fitted range. The insights provided in this study hold substantial implications for the oil and gas industry, as predicting the rheological behavior of drilling fluids under varying temperatures and pressures within the annular region of the well is essential for efficient drilling planning, particularly in offshore fields.

A Comprehensive Review on Carbon Dioxide Sequestration Methods

Capturing and storing CO2 (CCS) was once regarded as a significant, urgent, and necessary option for reducing the emissions of CO2 from coal and oil and gas industries and mitigating the serious impacts of CO2 on the atmosphere and the environment. This recognition came about as a result of extensive research conducted in the past. The CCS cycle comes to a close with the last phase of CO2 storage, which is accomplished primarily by the adsorption of CO2 in the ocean and injection of CO2 subsurface reservoir formation, in addition to the formation of limestone via the process of CO2 reactivity with reservoir formation minerals through injectivities. CCS is the last stage in the carbon capture and storage (CCS) cycle and is accomplished chiefly via oceanic and subterranean geological sequestration, as well as mineral carbonation. The injection of supercritical CO2 into geological formations disrupts the sub-surface’s existing physical and chemical conditions; changes can occur in the pore fluid pressure, temperature state, chemical reactivity, and stress distribution of the reservoir rock. This paper aims at advancing our current knowledge in CO2 injection and storage systems, particularly CO2 storage methods and the challenges encountered during the implementation of each method and analyses on how key uncertainties in CCS can be reduced. CCS sites are essentially unified systems; yet, given the scientific context, these storage systems are typically split during scientific investigations based on the physics and spatial scales involved. Separating the physics by using the chosen system as a boundary condition is a strategy that works effectively for a wide variety of physical applications. Unfortunately, the separation technique does not accurately capture the behaviour of the larger important system in the case of water and gas flow in porous media. This is due to the complexity of geological subsurface systems, which prevents the approach from being able to effectively capture the behaviour of the larger relevant system. This consequently gives rise to different CCS technology with different applications, costs and social and environmental impacts. The findings of this study can help improve the ability to select a suitable CCS application method and can further improve the efficiency of greenhouse gas emissions and their environmental impact, promoting the process sustainability and helping to tackle some of the most important issues that human being is currently accounting global climate change. Though this technology has already had large-scale development for the last decade, some issues and uncertainties are identified. Special attention was focused on the basic findings achieved in CO2 storage operational projects to date. The study has demonstrated that though a number of CCS technologies have been researched and implemented to date, choosing a suitable and acceptable CCS technology is still daunting in terms of its technological application, cost effectiveness and socio-environmental acceptance.

Statistical field theory of mechanical stresses in Coulomb fluids: general covariant approach vs Noether’s theorem

In this paper, we introduce a statistical field theory that describes the macroscopic mechanical forces in inhomogeneous Coulomb fluids. Our approach employs the generalization of Noether’s first theorem for the case of a fluctuating order parameter to calculate the stress tensor for Coulomb fluids. This tensor encompasses the mean-field stress tensor and fluctuation corrections derived through the one-loop approximation. The correction for fluctuations includes a term that accounts for the thermal fluctuations of the local electrostatic potential and field in the vicinity of the mean-field configuration. This correlation stress tensor determines how electrostatic correlation affects local stresses in a nonuniform Coulomb fluid. We also use a previously formulated general covariant methodology (Brandyshev and Budkov 2023 J. Chem. Phys. 158 174114) in conjunction with a functional Legendre transformation method and derive within it the same total stress tensor. We would like to emphasize that our general approaches are applicable not only to Coulomb fluids but also to nonionic simple or complex fluids, for which the field-theoretic Hamiltonian is known as a function of the relevant scalar order parameters.

Evolution of solitary hydroelastic strain waves in two coaxial cylindrical shells with the Schamel physical nonlinearity

The paper considers the formulation and solution of the hydroelasticity problem for studying wave processes in the system of two coaxial shells containing fluids in the annular gap between them and in the inner shell. We investigate the axisymmetric case for Kirchhoff–Lave type shells whose material obeys a physical law with a fractional exponent of the nonlinear term (Schamel nonlinearity). The dynamics of fluids in the shells is considered within the framework of the incompressible viscous Newtonian fluid model. The derivation of the Schamel nonlinear equations of shell dynamics makes it possible to develop a mathematical formulation of the problem, which includes the obtained equations, the dynamics equations of two shells, the fluid dynamics equations and the boundary conditions at the shell-fluid interfaces and at the flow symmetry axis. The asymptotic analysis of the problem is performed using perturbation techniques, and the system of two generalized Schamel equations is obtained. This system describes the evolution of nonlinear solitary hydroelastic strain waves in the coaxial shells filled with viscous fluids, taking into account the inertia of the fluid motion. In order to determine the fluid stress at the shell-fluid interfaces, we perform linearization of the fluid dynamics equations for fluids in the annular gap and in the inner shell. The linearized equations are solved by the iterative method. The inertial terms are excluded from the equations in the first iteration, while, in the second iteration, these are the values found in the first iteration. A numerical solution of the system of nonlinear evolution equations is obtained by applying a new difference scheme developed using the Gröbner basis technique. Computational experiments are performed to investigate the effect of fluid viscosity and the inertia of fluid motion in the shells on the wave process. In the absence of fluids in the inner shell, the results of calculations demonstrate that the strain waves in the shells during elastic interactions do not change their shape and amplitude, i.e., they are solitons. The presence of viscous fluid in the inner shell leads to attenuation of the wave process.

Evaluation of an efficient data-driven ANN model to predict agglomerate collisions within Euler–Lagrange simulations

In this study, a recently developed data-driven model for the collision-induced agglomerate breakup (CHERD 195, 2023) is evaluated. It is especially intended for Euler–Lagrange simulations of flows with high mass loadings, where coupled CFD–DEM predictions are too expensive. Therefore, a surrogate model relying on the hard-sphere approach in which agglomerates are represented by effective spheres was developed. Based on a variety of DEM simulations, artificial neural networks were trained to predict the post-collision number of arising fragments, their size distribution and their velocities. In the present contribution, the agglomerate collision model is assessed using the particle-laden flow through a T-junction. Since two fluid streams with agglomerates are injected at both opposite ends, the setup is particularly suitable for investigating breakage caused by collisions. Two flow configurations (laminar flow at Re = 130 and turbulent flow at Re = 8000) and two different powders (primary particle diameter of 0.97 and 5.08 micrometers) are taken into account. The latter allows to study the influence of the strength of the agglomerates on the collision-induced breakage. The laminar case offers the possibility to evaluate the effect of the collision angle in detail. The collision-induced breakage proves to be the most dominant deagglomeration mechanism in both the laminar and turbulent flow scenario. Nevertheless, the role of the fluid stresses and especially the drag stress becomes more prominent in the turbulent case, while in the laminar flow their effects are negligible.

The Correlation Between Motivation and Self-Care Mangement Among Leukemia Patients Based on Orem's Theory

Introduction: Leukemia is one of the most diagnosed types of cancer and a cause of death worldwide. Patients who experience severe side effects of cancer treatment tend to experience less than optimal self-care management. Leukimia patients in treatment often complain of fatigue, weakness, lack of energy, and nausea which hinder them in self-care management. The purpose of this study was to determine the relationship between motivation and self-care management. Methods: This study used an analytic descriptive research design with a cross sectional approach. Population on this research were members of Chronic Granulocytic Leukemia (it is known as “ELGEKA”), East Java, Indonesia. The sample size was 69 respondents using purposive sampling. The independent variable was motivation and the dependent variable was self-care management. Data was analyzed using Spearman Rho analysis with level of significance 0.05. Results: The results of this study indicated that there was a relationship between motivation and self-care management (p=0.000) and (r=0,531). Discussion: Motivation has a significant relationship with self-care management in leukemia patients based on Orem's theory. The higher the motivation, the higher self-care management. Good self-care management involves nutrition and fluid management, physical activity, stress management, complementary therapy, information and support seeking, and medication adherence. Conclusion: Nurses have an important role in identifying and increasing patient motivation to carry out self-care management and changing their attitudes to improve health and disease care. The recommendation for future researchers is to develop research with interventions to improve self-care management in leukemia patients.

Quasi-Static Modelling of a Full-Channel Effective Magnetorheological Damper with Trapezoidal Magnetic Rings.

Magnetorheological damper (MRD) has been successfully applied to vehicle suspension systems as an intelligent core component. Most conventional MRDs have closed rectangle-shaped magnetic circuits, resulting in a short effective working length and negligible damping force. To address the above issues, a novel full-channel effective MRD with trapezoidal magnetic rings (FEMRD_TMR) is proposed. The trapezoidal magnetic ring can shunt the magnetic circuit, distributing it evenly along the damping channel and increasing the effective working length. Additionally, which has the same variation trend as the magnetic flux through it, makes the magnetic induction intensity distribution more uniform to reduce the magnetic saturation problem. Theoretically analyzing the damping characteristics of the FEMRD_TMR, a quasi-static model is developed to forecast the output damping force. The structural design of MRD is challenging since conventional quasi-static models rely on the yield stress of magnetorheological fluid (MRF) to reflect the rheological property, which cannot be directly observed and is challenging to calculate. The Takagi-Sugeno (T-S) fuzzy neural network and a unique magnetic circuit computation are offered as a novel quasi-static modeling approach to address the issue. The MRF's yield stress is linearized into magnetic induction intensity functions by the T-S fuzzy neural network and then converted into the MRD's structural size by the special magnetic circuit calculation. Therefore, the proposed quasi-static model can directly reflect the relationship between the damping force and structure size, simplifying MRD's structure design. The novel quasi-static model is shown to be more straightforward and understandable than the conventional Bingham quasi-static model and to have approximately accurate damping force prediction when compared to experimental data.