Boyuan Yin

Carbon black (CB)‐filled rubbers are extensively employed as damping elements across multiple fields, yet their mechanical performance degrades unavoidably under concurrent thermal and mechanical loading in service. To this end, accelerated artificial thermo‐oxidative aging experiments, equilibrium swelling measurements and dynamic mechanical analysis (DMA) tests of CB‐filled rubber under various aging temperatures were carried out to better understand the mechanical property degradation mechanism. It was observed that thermo‐oxidative aging temperature and time had a great effect on the Payne effect of CB‐filled rubber. Maier‐Göritz (MG) model was used to describe the Payne effect of CB‐filled rubber, and the network density evolution was discussed by use of MG model parameters. Meanwhile, qualitative analysis of crosslink density was conducted on the basis of network density evolution results, which were verified by equilibrium swelling tests in order to accurately reveal the mechanism of the Payne effect of CB‐filled rubber. It was noticed that both qualitative analysis results and equilibrium swelling tests ones exhibited the same evolution trend with an increase of aging temperature and time. In this work, the crosslink density evolution was comprehensively investigated from experimental and theoretical analysis, which can provide guidance value to better understand the degradation mechanism of CB‐filled rubber.

During service in engineering fields, the performance of carbon black (CB)/silica-filled rubber suffers degradation because of the influence of aging. In the process of reproducing the mechanical behavior of CB/silica-filled rubber, many constitutive models have been proposed. However, the model selection strategy taking the aging effect into consideration is still unclear, especially the classical model selection strategy. In this work, the effects of thermo-oxidative and ultraviolet aging on the nonlinear viscoelasticity of CB/silica -filled rubber were investigated using dynamic mechanical analysis tests. It was found that aging conditions had a great effect on the nonlinear viscoelasticity of CB/silica -filled rubber. Meanwhile, the degradation mechanisms were discussed on the basis of the existing works. To accurately reproduce the nonlinear viscoelasticity degradation, classical models, such as the Kraus model and Maier–Göritz model, were used to describe the experimental data. In the reproducing process, fitting correlation coefficients and root mean square error were used to verify the reliability of classical models. Comparingsimulation results and experimental ones, it was found that the Maier–Göritz model was more reliable under all aging conditions. This work will contribute to a model selection strategy and a deeper understanding of the degradation mechanism.

The crosslinked binders formed by using glycidyl azide polymer (GAP) as the binder matrix and bis-propargyl succinate (BPS) as the curing agent have good application prospects in the field of solid propellants. Aiming at the shortcomings of traditional experimental research, such as high cost, and molecular dynamics (MD) simulation, which are time-consuming for complex combination problems, this study will realize accurate prediction of the mechanical properties of binders through machine learning (ML) based on the molecular simulation dataset. Firstly, 273 sets of GAP-BPS binder models under different conditions were formed based on 21 crosslinking degrees and 13 temperatures, and MD simulation and mechanical property simulation were carried out. Then, the initial conditions of molecular simulation (crosslinking degree, temperature) and structural parameters (free volume) were taken as features, and the bulk modulus and shear modulus were taken as labels to form the dataset. Three machine learning models were trained and evaluated based on this dataset to test their prediction performance. Based on the cross-validation results, the Tabular Prior Data Fitting Network (TabPFN) exhibits the highest average prediction values (the average R² for bulk modulus and shear modulus were 0.9684 and 0.8827, respectively). But the significance analysis reveals that TabPFN significantly outperforms the RF model only in predicting bulk modulus. In subsequent prediction tasks with smaller datasets, TabPFN achieves superior average prediction values compared with RF and XGBoost.

Carbon black (CB)-filled rubber materials are extensively used in civil engineering seismic isolation. However, CB-filled rubber materials often experience mechanical property degradation because of exposure to environmental factors. To better understand the influences of thermo-oxidative, ultraviolet and ozone aging on mechanical property degradation, uniaxial tension and dynamic mechanical analysis (DMA) tests were carried out. In the uniaxial tension tests, the stress strength and elongation decreased with an increase in aging time. In the DMA tests, the effective temperature ranges decreased by 3.4–14%. And the neo-Hookean model was applied to simulate the hyperelasticity of CB-filled rubber materials. The relationship between the elastic modulus (a constant of the neo-Hookean model) and aging time was established, which provided a qualitative relationship between crosslink density and aging time. In addition, the dispersion of the CB aggregate was investigated using an atomic force microscope (AFM). The results indicated that the mechanical property degradation might be closely related to the aggregate diameter. This paper establishes a bridge between the microstructure and mechanical properties of CB-filled rubber materials, which can improve the understanding of the mechanical property degradation mechanisms of rubber materials and the fabrication of rubber components.

Carbon black (CB)-filled rubber has been widely used in engineering. However, its time-dependent behavior, such as creep, is undesirable during the service process. In addition, the long-term creep test is time- and cost-consuming. To this end, the objective of this paper aims to predict the creep behavior from the short-term storage modulus by use of the collocation method. First, the master curve of storage modulus was constructed based on the time–temperature superposition principle (TTSP), and the validation of shift factors was verified by use of the Williams–Landel–Ferry (WLF) equation. Second, the generalized Kelvin model was used to describe the master curve of storage modulus by use of the collocation method, and the corresponding parameters were obtained. Compared with the existing works, the collocation method had the advantages of avoiding the occurrence of waviness of the fitting curve. Lastly, the creep compliance of CB-filled rubber was calculated by substituting the fitting parameters into the creep compliance expression. In order to verify the reliability of the calculation result, the creep tests were carried out. It was obvious that the calculation result is in good agreement with the experimental one with a RMSE value of 0.0055, which means that the calculation result is reliable.

Carbon black (CB)‐filled rubber has been extensively used in many engineering fields. In the service process, CB‐filled rubber tends to experience mechanical properties degradation resulting from environmental factors, such as thermo‐oxidative, ultraviolet, and ozone aging. To better understand the degradation mechanism, dynamic mechanical analysis tests were conducted, and the Maier‐Göritz (MG) model was used to analyze the crosslink density evolution with aging time. It was found that thermo‐oxidative, ultraviolet, and ozone aging had a great effect on the Payne effect and hysteresis loss. Based on experimental results, the MG model was used to simulate the Payne effect under various aging conditions, and the constants of the MG model were obtained. It was observed that the simulating results were in good accordance with the experimental ones. In addition, a novel method was proposed to evaluate the crosslink density evolution with aging time based on the constants of the MG model. The reliability of the proposed method was verified by the existing results, which indicated that the crosslink density was one of the dominant factors affecting the Payne effect and hysteresis loss of CB‐filled rubber in the process of aging.

It is found that the performance of the rubber bearing is dominated by the carbon black (CB) filled rubber whose dynamic mechanical properties are sensitive to frequency, temperature, and strain amplitude. Due to viscoelasticity, the hysteresis loss represents energy dissipation, which can reflect the damping capacity of the CB‐filled rubber. Besides, the energy dissipation is positively correlated with the loss modulus. However, in practice, the rubber bearing is only considered a structural vibration measure, which keeps in service for a long time under various loading conditions. The current research on the accelerated prediction method of the loss modulus and hysteresis loss of CB‐filled rubber is limited. To this end, dynamic mechanical tests are carried out. Based on the time–temperature superposition principle (TTSP), the master curve of long‐term dynamic mechanical properties can be obtained, and the accuracy of shift factors is verified by the use of the Williams–Landel–Ferry (WLF) equation. When the temperature rises above −10°C, it is obvious that there is a linear relationship between the shift factor and temperature. Therefore, an empirical accelerated prediction method of the loss modulus and hysteresis loss of CB‐filled rubber is proposed by the use of the linear relationship. The results show that the empirical method is very useful to predict the loss modulus and hysteresis loss of CB‐filled rubber, which indicates that time and cost can be significantly reduced because of the simplicity in comparison with the WLF equation.Highlights: Effect of temperature, frequency, and prestrain on the dynamic viscoelasticity. A linear relationship between shift factor and loading condition is proposed. The linear relationship is superior from the aspect of time and cost.