Cohesive Forces Research Articles

Social epidemiology of COVID-19 in Argentina: an approach from the perspective of medical personnel

This article explores from a socio-epidemiological perspective the syndemic character acquired by the COVID-19 pandemic at the hospital level, belonging to the public health system in Argentina. Methodologically, semi-structured interviews were conducted with hospital workers from the southern area of the metropolitan region to the Federal Capital, by virtual meeting platforms, between the months of May and November 2021. The analysis of the narratives obtained about the experience of workers, makes it possible to understand certain dimensions that contribute to deepening the deterioration of working conditions, weakening and undermining the care and self-care processes of the workers themselves, linked not only to the imponderables of the pandemic being analyzed (while this occurs), but also to previous problems and are magnified during the epidemiological emergency. In this regard, the emergence of spaces for dialogue-collective work among workers is observed, as a fundamental cohesive force to promote any change or social transformation that materializes in a concrete way within the institution.

Preface

The 2022 International Conference on Mechanical, Aerospace Technology and Materials Application (MATMA 2022) was successfully on September 23-25, 2022 held in Chengdu, China (virtual conference). MATMA 2022 promoted the development and application of theory and technology in related fields in universities and enterprises, and established business or research contacts for participants to seek global partners in their future careers.We had the honor of having invited Prof. Yunqing Rao from Huazhong University of Science and Technology, China to serve as our General Conference Chair. The conference was composed of keynote speeches, oral presentations, and online Q&A discussion, bringing together 90 individuals worldwide. Firstly, keynote speakers were each allocated 30-45 minutes to hold their speeches. Then in the next part, oral presentations, the excellent papers we had selected were presented by their authors one by one.During the conference, four distinguished professors were invited to address their keynote speeches. Among them, Prof. Bing Wang from Fuzhou University, China addressed a thought-provoking speech on Structural and Functional Integration of Foldable Mechanical Composite Hinges. In the speech, he focused on a bistable composite tape-spring structure, which is a thin-walled, open slit composite tube, that is stable in its extended and coiled configurations. This inherent behavior makes it ideal for the applications to foldable mechanical hinge designs: there are great opportunities in replacing the conventional hinge assemblies. And then, Prof. Eckart Meiburg from University of California Santa Barbara, US made a speech on Exploring Multiphase Flow Processes via Particle-resolving Simulations. He presented an overview of particle resolving Navier Stokes simulations for a variety of multiphase flow processes, and discussed several different applications, with one focus on the influence of cohesive forces in such flows, especially the formation and break-up of aggregates consisting of several individual particles. Their wonderful speeches had triggered heated discussion in the conference. And every participant praised this conference for disseminating insightful knowledge.The proceedings of MATMA 2022 are a compilation of the accepted papers and represent an interesting outcome of the conference. These papers feature but are not limited to the following topics: Applied Mechanics, Aerodynamics and Control, Modeling and Simulation, Industrial Tribology, etc. All the papers have been checked through rigorous review and processes to meet the requirements of publication.We would like to express our sincere gratitude to all the keynote speakers, peer reviewers, and all the participants who supported and contributed to MATMA 2022. Particularly, our special thanks go to the Journal of Physics: Conference Series, for the hard work of all its colleague in publishing this paper volume. We firmly believe that MATMA 2022 had turned out to be a forum for excellent discussions that enable new ideas to come about, promoting collaborative research.The Committee of MATMA 2022List of Committee member is available in this Pdf.

Simulation of mixed mode I-II crack propagation in concrete using toughness-based crack initiation-propagation criterion with modified fracture energy

The fracture behaviors of quasi-brittle materials such as concrete were evaluated based on the crack propagation criterion, and among all criterions reported in the literature, the toughness-based crack initiation-propagation (TCIP) criterion capable of capturing simultaneously the crack initiation and propagation was widely used. Recently, a modified fracture parameter was introduced to ensure the energy balance relationship, however, the use of the modified parameter-based TCIP criterion was limited only to mode-I fracture of quasi-brittle materials. In the context of mixed-mode fracture problems, an extra effort was made in this paper to extend the modified parameter-based TCIP criterion previously developed for the mode-I fracture to the mixed mode I-II fracture. Application of the extended criterion was performed on three-point bending beams with offset and multi-segment notches through finite element analysis, in which the cohesive force at the fracture process zone was applied through nonlinear spring elements. On concrete materials, the full crack trajectories for mixed mode I-II fracture and nonlinear mechanical responses such as P-δ, P-CMOD, and P-CMSD curves were numerically obtained in the present paper. With the modified fracture energy parameter, good consistency was found between the numerical results given by the reported model and experiments. Nevertheless, it must be admitted that the use of TCIP criterion with the modified fracture energy parameter on concretes was bounded, it would be more prominent on other geomaterials such as rocks, for both static and dynamic analysis.

Detecting Early-Stage Cohesion Due to Calcium Silicate Hydration with Rheology and Surface Force Apparatus.

Extremely robust cohesion triggered by calcium silicate hydrate (C-S-H) precipitation during cement hardening makes concrete one of the most commonly used man-made materials. Here, in this proof-of-concept study, we seek an additional nanoscale understanding of early-stage cohesive forces acting between hydrating model tricalcium silicate (C3S) surfaces by combining rheological and surface force measurements. We first used time-resolved small oscillatory rheology measurements (SAOSs) to characterize the early-stage evolution of the cohesive properties of a C3S paste and a C-S-H gel. SAOS revealed the reactive and viscoelastic nature of C3S pastes, in contrast with the nonreactive but still viscoelastic nature of the C-S-H gel, which proves a temporal variation in the cohesion during microstructural physicochemical rearrangements in the C3S paste. We further prepared thin films of C3S by plasma laser deposition (PLD) and demonstrated that these films are suitable for force measurements in the surface force apparatus (SFA). We measured surface forces acting between two thin C3S films exposed to water and subsequent in situ calcium silicate hydrate precipitation. With the SFA and SFA-coupled interferometric measurements, we resolved that C3S surface reprecipitation in water was associated with both increasing film thickness and progressively stronger adhesion (pull-off force). The lasting adhesion developing between the growing surfaces depended on the applied load, pull-off rate, and time in contact. These properties indicated the viscoelastic character of the soft, gel-like reprecipitated layer, pointing to the formation of C-S-H. Our findings confirm the strong cohesive properties of hydrated calcium silicate surfaces that, based on our preliminary SFA measurements, are attributed to sharp changes in the surface microstructure. In contact with water, the brittle and rough C3S surfaces with little contact area weather into soft, gel-like C-S-H nanoparticles with a much larger surface area available for forming direct contacts between interacting surfaces.

The risk assessment of landslide hazards in the Badong section of Three Gorges using the variable fuzzy set theory

The risk assessment of landslide hazards has a tremendous influence on people’s lives and property safety; therefore, its investigation is significant. The stratigraphic lithology, degree of weathering, relationship between the structural plane and slope direction, cohesive force, angle of internal friction, severity, average slope degree, height of slope, and type of landslide are adopted as the evaluation factors first. Second, an assessment model is developed based on the variable fuzzy set theory. In addition, the proposed model is utilized to assess the landslide hazards in the Badong section of Three Georges in China. Finally, the results demonstrate that the results derived from the proposed model are consistent with the current specifications; the accuracy rate reaches 83%. The method can determine the risk level of landslide hazards and provide an alternative scheme. Hence, this study can accurately present a new approach for assessing landslide hazards in the future.

Strain Field Evolution and Constitutive Model of Coal considering the Effect of Beddings

Abstract In order to study the bedding effect of coal and rock deformation, the surface deformation fields of coal and rock at different bedding angles were obtained by means of digital image correlation (DIC). By optimizing the statistical index describing the nonuniformity of strain field, the initiation and evolution characteristics of deformation localization were analyzed quantitatively. The concepts of equivalent cohesive force and equivalent tensile strength were put forward, and a transverse isotropic constitutive model of coal and rock was established. The results show that the maximum shear deformation field of uniaxial compressed coal and rock in parallel bedding is more likely to show the three-stage characteristics of uniform stage, localization stage, and failure stage. In the vertical and parallel bedding directions, the modified statistical index curve of coal and rock in the process of uniaxial compression shows typical two-stage characteristics. When loading perpendicular to bedding, the starting stress of deformation localization of coal and rock is closer to the peak strength, and when loading parallel to bedding, coal and rock are easier to show localization characteristics.

Red Mud-Amended Soil as Highly Adsorptive Hybrid-Fill Materials for Controlling Heavy Metal Sewage Seepage in Industrial Zone.

With the rapid development of urbanization, the problem of environmental pollution is becoming more and more serious. As a major pollutant, heavy metals have caused serious contamination in soil and groundwater. In order to prevent the diffusion of heavy metals in the soil from industrial sewage, the concept of hybrid-fill layer construction improved by red mud was proposed in this study. This study examines the adsorption capacities of lead and zinc ions and engineering characteristics on red mud-amended soils by direct shear, permeability, adsorption, desorption batch and column tests. Two mixing methods, full particle size displacement mixing and partial particle size displacement mixing, were adopted. The results showed that red mud effectively increased the adsorption capacity of soil to heavy metal ions, and the desorption rate of ions after adsorption was less than 3%, which had good anti-desorption ability. The optimum content of red mud in hybrid-fill material can be determined as 20%. The direct shear test showed that the internal friction angle of hybrid-fill material was 38.9°, and the cohesive force was 30.3 kPa, which met the engineering strength requirements of foundation materials. Based on the test results, red mud can be used as a barrier material to prevent heavy metal contamination in industrial sewage from diffusion, which controls not only heavy metal contamination but also consumes industrial by-products.

Innovative Ground Improvement with Chemical Grouts: Potential and Limits of Partial Saturation with Polymers

Nowadays, polymers are well-established in geotechnical applications, for example as grouting material for soil and rock stabilization, or as grouting material for anchorages. Concerning ground improvement, the polymers act as a binder that, if cured, holds the grains together by adhesive and cohesive forces. This special characteristic enables the use of less material and therefore saves costs but requires detailed knowledge of the material behavior to avoid application errors. The subject of this research work are two different polymers, which are used for partial saturation of the ground. For the investigation of the mechanical and hydraulic properties of the ground improvement, the geotechnical testing program on the composite material of polymers and gravel is extended by special tests, such as rheometer tests, for chemical grouts. If the polymers are used correctly, the composite material can achieve a load-bearing capacity comparable to that of concrete while the material remaining permeable. This is highlighted by strength tests on the composite material. Finally, the numerical calculation of a track ballast stabilization, using PFC-FLAC3D coupling, demonstrates the potential of the polymers for practical application and that even difficult ground conditions can be handled with it.

Deformation and Sensitivity Analysis of Lateral Pile of Foundation Pit under Vertical Load

In order to explore the side deformation of the retaining piles of the foundation pit under vertical load and the sensitivity analysis of influencing factors, based on the foundation pit of a subway station of Nanning Metro Line 5, firstly, the presence of vertical load is compared and analyzed through field monitoring data. Then use FLAC3D to establish a numerical model to verify the accuracy of the numerical model by comparing with the monitoring data, and then study the maximum displacement of each factor on the lateral pile based on the numerical model, and carry out sensitivity analysis of influencing factors through grey correlation method. The results show that: the pre-acting vertical load increases the maximum displacement of the lateral pile by 20.2%, and the position of the maximum displacement of the lateral pile is lowered by 3m, which weakens the horizontal bearing capacity of the retaining pile, but has little effect on the deformation of the lateral pile; the vertical load increases When it is 3 times larger, the maximum displacement of the lateral pile is close to the pre-warning value, and the adverse effects of the vertical load should be fully considered. The second steel support diameter can be adjusted first in the design optimization; the cohesive force and internal friction angle of the soil parameters affect the surrounding pile. The side deformation has a greater impact and should be carefully determined based on indoor tests and local engineering experience.

Using PVA and Attapulgite for the Stabilization of Clayey Soil.

Considering that, in the context of the ecological restoration of a large number of exposed rock slopes, it is difficult for existing artificial soil to meet the requirements of mechanical properties and ecological construction at the same time, this paper investigates the stabilization benefits of polyvinyl acetate and attapulgite-treated clayey soil through a series of laboratory experiments. To study the effectiveness of polyvinyl acetate (PVA) and attapulgite as soil stabilizer, a triaxial strength test, an evaporation test and a vegetation growth test were carried out on improved soil with different amounts of PVA content (0, 1%, 2%, 3%, and 4%) and attapulgite replacement (0, 2%, 4%, 6%, and 8%). The results show that the single and composite materials of polyvinyl acetate and attapulgite can increase the peak deviator stress of the sample. The addition of polyvinyl acetate can improve the soil strength by increasing the cohesion of the sample; the addition of attapulgite improves the soil strength mainly by increasing the internal friction angle of the sample. The strength of the composite is greatly improved by increasing the cohesion and internal friction angle of the sample at the same time. The effect of adding materials increased significantly with increasing curing age. Moreover, polyvinyl acetate and attapulgite improve the soil water retention of the soil by improving the water-holding capacity, so that the soil can still ensure the good growth of vegetation under long-term drought conditions. The scanning electron microscopy (SEM) images indicated that the PVA and attapulgite of soil affect the strength characteristics of soil specimens by the reaction of PVA and water, which changes the structure of the soil and, by the interweaving of attapulgite soil particles, acts as the skeleton of the aggregate. Overall, PVA and attapulgite can effectively increase clayey soil stability by improving the cohesive force and internal friction angle of clayey soil.

A novel force balance model for predicting defluidization of ilmenite in a fluidized bed reactor

Ilmenite particles are readily defluidized when they are reduced in a fluidized bed reactor because nano-micro iron nuclei that precipitate on the particle surface are adhesive and tend to aggregate. We propose herein a novel force balance model with which to predict defluidization phenomena. This model is based on the particle cohesion force comprising the sum of the cohesion forces for surface asperities. As the surface coverage of iron particles increases with the extent of reduction, the cohesion forces of the particles gradually increase and eventually trigger defluidization. The surface coverage predicted by the model agrees well with experimental results for 88.4 ∼ 154.7 μm particles and the temperature range 700 ∼ 850 °C. The new force balance model reveals that particle size, sphericity, and temperature play key roles in defluidization of ilmenite during reduction. Defluidization occurs readily for fine and irregular particles, especially at high temperatures. Our model combines asperity, surface coverage, and particle sphericity to make a more general prediction.

Factors determining the flowability and spreading quality of gas-atomized Ti-48Al-2Cr-2Nb powders in powder bed fusion additive manufacturing

A high-quality powder bed is necessary for obtaining high-quality products using powder bed fusion-based additive manufacturing. In this study, mechanical ball milling was suggested to improve the flowability and spreadability of gas-atomized (GA) Ti–48Al–2Cr–2Nb powder in the powder bed fusion additive manufacturing process. The deformation mechanism of the GA powder significantly differed depending on the ball milling media. Surface grinding mainly occurred during Al 2 O 3 ball milling, while the pulverization was dominant in WC ball milling because of the higher impact force. The flowability of the GA powder under dynamic conditions was improved after Al 2 O 3 and WC ball milling owing to the decreased cohesive force. The high cohesive force in the GA powder under dynamic conditions was attributed to the electrostatic force caused by charge accumulation on the oxide film. The packing density of GA powder was increased after WC ball milling despite the formation of numerous irregular particles owing to the synergetic effect of rapid energy dissipation, minimized wall effect, and void filling effect. Furthermore, the spreadability of the GA powder was improved by ball milling because of the decrease in the cohesive force. Therefore, it was demonstrated that the flowability and spreadability of the GA powder can be improved via ball milling because of changes in particle size, shape, and surface properties. • Flowability of GA powder under the dynamic condition was improved after ball milling owing to the decreased cohesion force. • High cohesive force in GA powder was mainly attributed to the electrostatic force caused by charge accumulation on the oxide film. • Spreadability of GA powder was improved after ball milling due to the decreased cohesion force.

Extraction, characterization and epoxidation of Cassia fistula (Indian laburnum) seed oil: A bio-based material

Vegetable oils are rich source for obtaining most sustainable and green chemical compounds for various industrial applications. Oil from the seeds of locally grown plant Cassia fistula was extracted using Soxhlet apparatus using n-hexane as solvent. The fatty acid composition of the extracted oil (CFSO) was established by GC analysis. The epoxidation of the unsaturated fatty acids of triglyceride nature was carried out to get the epoxidated compound (ECFSO). Both the compounds were characterized by FTIR and 1H NMR spectra. The physicochemical properties such as acid value, iodine value, epoxy equivalent and oxirane oxygen content of both the compounds were measured. The results confirm the complete epoxidation on the unsaturated double bond portion of the alkyl chains of triglyceride. Thermal decomposition stability of the samples was established from the dynamic thermo gravimetric analysis (TGA) and derivative thermogravimetry (DTG). The decomposition of the samples occurred in a single step. ECFSO has relatively more thermal stability over the precursor CFSO. Integral and differential methods were used in the thermokinetic analysis of the data at different heating rates to calculate the activation energies (Ea) for the decomposition. It was revealed that the ECFSO sample decomposes with high Ea than its precursor. High sensitive differential scanning calorimetric (DSC) traces were used to determine the melting, pour, and cloud points. The pristine oil sample has displayed both the pour and cloud points while ECFSO showed only pour point, indicating the presence of cohesive intermolecular forces among the molecules of later. The Density functional theory (DFT) calculations were performed on CFSO, ECFSO, and the methyl esters of the fatty acids of triglyceride to get the information on the changes in the IR characteristics upon epoxidation and also to calculate the HOMO-LUMO energies, band gap, molecular electrostatic potentials and quantum chemical descriptors to assess the effect of epoxidation and influence of fatty acids of triglyceride on the reactivity.

Study on the bonding performance between reactive powder concrete and steel bar

The performance of reactive powder concrete (RPC) is much higher than that of ordinary concrete, and the engineering application is gradually increasing. The bond failure process and bond slip between RPC and reinforcement will show new characteristics. It is necessary to study the bond behavior between RPC and steel bar. The direct drawing test was carried out on the 36 bonding specimens in order to study the bond performance between steel bar and reactive powder concrete. The research shows that the cohesive force consists of three parts: the mechanical bite force produced by the mechanical occlusion between the reinforcing rib and the RPC; The cementing force produced by chemical reaction between RPC component and surface material of reinforcement; Friction between reinforcement and surrounding RPC. The application of ultrahigh strength and various cementitious materials make the Bonding strength between rebar and RPC significantly higher than that of normal concrete. This study can provide reference for the reinforcement anchorage design of RPC structure.

Smoothed particle hydrodynamics for cohesive dense granular media

• An elastic–viscoplastic constitutive model for cohesive dense granular media is built. • Rheological model considering cohesion for liquid-like phase is put forward. • The solid-like phase and liquid-like phase are both modelled and simulated. • Smoothed particle hydrodynamics was first used for cohesive dense granular media. • Cohesive force plays an important role in granular pile collapse, flow and depositing. Dense granular media with cohesion exist widely in nature. A constitutive model that considers cohesion in terms of solid-like and liquid-like phases in dense granular media was designed in this study. In this new model, a linear elastic–plastic constitutive relationship based on the Drucker–Prager yield criterion affected by the parameters of cohesion was used to describe the solid-like phase. A viscoplastic constitutive model based on rheology, which also considers cohesion, was obtained through formula derivation for the liquid-like phase after plastic yielding. The conversion and transitional relationships from elastic to elastic-micro viscoplastic and then to complete elastic–viscoplastic were built. Smoothed particle hydrodynamics was adopted to solve the new model discretely, and the relationship between smoothed and actual particles and an approach employed to avoid particle aggregation caused by cohesion were illustrated. Several typical cases including the collapse of cohesive granular accumulation, collapse of dry and wet granular column, and flow of cohesive powder in a rotating drum were used for verification. A comparison between cohesive and dry granular flows and among numerical results, experimental results, and those of other numerical methods proved that the proposed model and algorithm are effective for simulating dense granular flow with cohesion; further, they provide a valid approach to describe issues of granular flow with veritable cohesion that exist in nature.

Improved Flowability and Wettability of Whey Protein-Fortified Skim Milk Powder via Fluidized Bed Agglomeration.

Recently, protein-fortified milk powders are being widely consumed in Korea to prevent sarcopenia, and the demand for high-protein food powders is continuously increasing in the Korean market. However, spray-dried milk proteins have poor flowability and wettability owing to their fine particle sizes and high inter-particle cohesive forces. Fluidized bed agglomeration is widely used to improve the instant properties of food powders. This study investigated the effect of fluidized bed agglomeration on whey protein isolate (WPI)-fortified skim milk powder (SMP) at different SMP/WPI ratios. The fluidized bed process increased the particle size distribution, and agglomerated particles with grape-like structures were observed in the SEM images. As the size increased, the Carr index (CI) and Hausner ratio (HR) values of the agglomerated WPI-fortified SMP particles exhibited excellent flowability (CI: <15) and low cohesiveness (HR: <1.2). In addition, agglomerated WPI-fortified SMP particles exhibited the faster wetting time than the instant criterion (<20 s). As a result, the rheological and physical properties of the WPI-fortified SMP particles were effectively improved by fluidized bed agglomeration. However, the fluidized bed agglomeration process led to a slight change in the color properties. The CIE L* decreased, and the CIE b* increased because of the Maillard reaction. The apparent viscosity (ηa,10) and consistency index (K) values of the rehydrated solutions (60 g/180 mL water) increased with the increasing WPI ratio. These results may be useful for formulating protein-fortified milk powder with better instant properties.

중국 쓰촨성 자웅 마나이 궈좡춤 전승방안

The Jiarong Manai Guozhuang Dance reflects the strong cohesion and potential centripetal force of the Tibetans, and fully demonstrates the life style and era of the Jiarong Tibetan people. Therefore, it was designated as China

Numerical investigation of the particle circulation characteristics in a tapered fluidized bed

PurposeThe objective of this study is to investigate several issues related to particle circulation within the TFB, including exploring an appropriate method to quantify particle circulation time, the effects of different operational parameters on particle circulation time, and the relationship between particle mixing and particle circulation.Design/methodology/approachThe computational fluid dynamics coupled with the discrete element method (CFD-DEM) is applied to investigate the particle circulation characteristics of a tapered fluidized bed (TFB). An approach for defining particle circulation, which accounts for the horizontal motion of each particle, is proposed to estimate particle circulation time.FindingsIt is found that the overall particle circulation in a TFB could be accelerated by increasing air velocity and wall inclination angle, while an increase in particle size and an increase in inter-particle cohesive forces decelerate particle circulation; the increase in the open area ratio of the central region of the air distributor would decelerate the particle circulation. Moreover, the particle circulation time and mixing rate are independent variables that describe the flow dynamics of particles from different perspectives.Practical implicationsA large part of fluidized beds in industrial applications can be classified as TFB. This study presents a numerical method to obtain detailed knowledge about particle circulation in a TFB, which is essential for the design, optimization, and control of related processes.Originality/valueThe particle circulation in a TFB is important but rarely investigated, and it is hard to be quantified using existing experimental approaches. The proposed numerical workflow reveals the characteristics of particle circulation from a particle-scale perspective.

Study on Mechanical Properties of the Compound Soil of Feldspathic Sandstone and Sand Based on Micro – level

It is of great practical significance to study the mechanical properties of composite materials of arsenic and sandstone to control the ecological environment in soft sandstone area. In order to understand the material and structural characteristics of composite materials under different compound proportions, the microstructure and the composition of the material elements were analyzed by the microscopic test and the test of mercury injection from the microscopic level. The dynamic three axis instrument was used to carry out the mechanical test under the different mixing ratio. The results showed that the main mineral components of feldspathic sandstone are quartz, albite, montmorillonite and calcite. The structure has the strength in the anhydrous state. When the water is saturated, the structure collapses, the cohesive force decreases rapidly, and it has the collapsibility; Due to the complexity of the structure and the optimization of the gradation, the permeability is greatly reduced; the macroscopic mechanics exhibits strain hardening and nonlinear characteristics.

Biaxial tensile test and meso damage numerical simulation of HTPB propellant

Aiming at the shortcomings of the current research on the mechanical properties of solid propellants under complex stress conditions, an effective cross-shaped test piece configuration and variable-scale biaxial tensile test method are designed in this paper, and the meso-simulation model of propellant is constructed by Micro-CT test and random filling algorithm. Then, based on the Hook-Jeeves method and the cohesive force model, the mechanical performance parameters of each mesoscopic component were obtained, and finally the damage evolution process of the propellant was numerically simulated. The results show that the stress–strain curve of the propellant under biaxial loading is similar to that of uniaxial stretching, and has obvious rate dependence and stress state dependence. The mechanical properties of the propellant under biaxial tensile loading are significantly lower than those in uniaxial stretching, and the maximum elongation is only 45–85% of that in uniaxial stretching. The fracture process of propellant can be divided into initial linear stage, damage evolution stage and fracture stage. The dewetting phenomenon generally occurs at the interface between the large-sized AP particles and the matrix. With the loading of the load, the pores formed by the dewetting and matrix tearing continue to converge into cracks and expand in the direction perpendicular to the resultant force, and finally fracture. The propellant dehumidifies more easily under high strain rate loading, but the degree of dewetting is lower when the same strain is reached.