Owing to their extensive application scope, elastomers that combine high strength and excellent self-healing efficiency have always attracted significant attention are still a contradiction. In this study, novel PU elastomer was prepared by combining rigid poly(amic acid) (PAA) chain segments 3,3-dithiodipropionic dihydrazide (DPH) containing sextuple hydrogen-bonding units disulfide bonds. The exhibited tensile of 50.1 MPa toughness 144.2 MJ/m3. PAA serve as framework, significantly...

Abstract Coarse-grained soil is a commonly used material in earth-rock dams and soft foundation projects. An accurate understanding of its permeability characteristics crucial to the safe design associated Due scale effect, outcomes indoor percolation tests on scaled soils often do not accurately represent coarse-grained with their original gradation. According previous studies, effect downsized materials mainly affected by maximum particle diameter dmax gradation structure particles, where...

Farm tractors in cultivation consume a big amount of fossil fuels and emit greenhouse gases to the atmosphere. Improving traction performance power transfer indices wheeled field terrain soil with higher (pull ability) at optimal travel reduction (TR) can optimize energy utilization. This study compares performance, fuel consumption, productivity, farm tractor equipped new drive wheel “rigid lugged (RLW)” conventional tire (CTW) tillage operations. Tractor RLW resulted 24.6 kN drawbar pull...

A mechanical property experiment was carried out on steel-polypropylene fiber-reinforced concrete after elevated temperatures by using a 50 mm diameter SHPB apparatus. The regulations of compressive strength, elastic modulus, Poisson’s ratio, and other properties under six heating temperature levels (normal temperature, 100 °C, 200 400 600 800 °C) three impact pressures (0.3 MPa, 0.4 0.5 MPa) were studied. Using ANSYS/LS-DYNA 19.0 numerical simulation software LS-PrePost post-processing...

The dilatancy deformation and particle breakage effects of coarse-grained soil have a significant influence on the safety stability high earth rock-fill dams. To study shear characteristics soil, four groups sample with different coarse grain contents were to conduct consolidated drained triaxial compression tests by DJSZ-150 large-scale test machine. results showed that volume changes significantly under deviation stress. samples underwent positive confining pressures 200 kPa 400 but...

Summary In discrete element method simulations, multi‐sphere particle is extensively employed for modeling the geometry shape of non‐spherical particle. A contact detection algorithm particles has been developed through two‐level‐grid‐searching. first‐level‐grid‐searching, each represented by a bounding sphere, and global space partitioned into identical square or cubic cells size D , diameter greatest sphere. The spheres are mapped in space. candidate can be picked out searching neighbor...

In order to clarify the relationship between different blade numbers and radial exciting force of rotary lobe pump rotor, five pumps with were researched based on dynamic mesh techniques using RNG k-ε turbulence model PISO algorithm. The internal flow characteristics in are compared influence mechanism transient structure inside rotor cavity revealed. Meanwhile, through numerical simulation experimental verification, comparative analysis prediction shows that relative error is less than...

Highlights An outer groove wheel fertilizer applicator with helical teeth was designed. The made the mass and kinetic energy more stable. rate sensitive to working length rotational speed. Abstract. plays an important role in making fertilization efficient, a called (OGWFA) is widely used middle of China. OGWFA traditional straight has pulsation phenomenon problems breaks application. To improve performance, designed staggered arrangement. angle parameter for (OGW), 47.5° considered...

Traction failure on loose terrain is common in conventional agricultural wheeled tractors due to poor traction ability and lower power transfer efficiency of drive wheels, which leads excessive energy consumption soil compaction agriculture. To overcome the problem, this paper presents a new design rigid lugged wheel for use field tillage operations. This was designed according operational requirements also provided with rubber pads smooth on-road drives. Kinematic dynamic analysis designs...

The rheological properties parameters of paddy soil affect the interaction between tillage tools and soil, thus influencing operation quality power consumption. In order to study effects methods moisture content on in middle lower reaches Yangtze River, uniaxial compression creep tests soils with four contents under no (moisture contents: 26.71%, 24.52%, 23.26%, 21.28%) plough 26.77%, 25.55%, 23.40%, 20.56%) were carried out using a TMS-PRO texture analyzer. curves obtained from tests,...

In order to improve the performance of tillage tool for straw incorporation in silty clay loam, a combined implement with plough and rotary tiller was designed. Its on power consumption investigated, types (CTSR CTDR) were compared traditional including sole type (SP DP), (RT), two-pass (SP+RT DP+RT) rice field experiment. The effect forward speed RT CTSR studied by DEM simulation. ratio coverage CTDR increased nearly 20% RT, stability coefficient depth CV surface evenness after also...

To realize real-time and accurate performance monitoring of large- medium-sized seed metering devices, a system was designed for devices based on LED visible photoelectric sensing technology pulse width recognition algorithm. Through an analysis the component pointing characteristics motion characteristics, layout components critical optimized. Single-grain were employed as objects, thresholds Ekangmian-10 cotton seeds Zhengdan-958 corn determined through threshold calibration experiments at...

The computational cost is expensive for CFD-DEM simulation, a larger time step and simplified model can be used to accelerate the simulation. relationship between stiffness overlap in non-linear Hertzian examined, reasonable determined by new single particle test. simulate dilute pneumatic conveying with different types of bends, its applicability verified compared traditional model. They are good agreement horizontal-vertical case vertical-horizontal case, show significant differences...

Grouting technology is playing an increasingly important role in engineering construction, but the theoretical research lags behind practice of grouting need. At present, on laws grouts rheological properties and grout diffusion are contents scientific workers. This paper researches time-dependent behavior viscosity, verifies commonly used water-cement ratio (W/C) 0.5, 0.6, 0.7 cement obey power-law fluid properties. Different water viscosity increases with increase gelation time....

Summary In the discrete element method (DEM) simulation for wear prediction, structural boundary is now represented extensively by triangular meshes with high resolution, which brings a huge computational cost. A DEM‐based predicting evolution of has been developed efficiency. The subjected to spherical elements in DEM combination inside triangles and fitting curved surface prediction. Wear prediction performed through series steps. each step, collision energies particles at are collected...

After the single-phase ground fault occurs in distribution network, a wealth of electrical transient characteristics are generated system. The system has that zero-sequence currents at both ends non-fault section similar and difference current is large. In this paper, method for location based on generalized S-transform energy remainder proposed. time-frequency matrix each band obtained through faulty current. By calculating between two normalizing it, with largest section. Lots simulation...

The agricultural digging device for lotus root make waterjet scour away the soil around to help it float up water surface by buoyancy on harvesting . performance of was investigated CFD-DEM simulation and experiment its optimization. Hertz-Mindlin with JKR model used as cohesive. shoes that depth increases increase jetting angle decrease diameter nozzle. preliminary trial verified this trend, revealed determined ratio. In field experiment, effects type nozzle, nozzle depth, ratio, breaking...

Purpose The purpose of this paper is to optimize the structure plough blades in a ploughshare mixer using discrete element method (DEM) simulations. Design/methodology/approach Using validated DEM model, three numerical tests are conducted determine how mixing performance evolves as structural parameters change. Results from analysis provide basis for optimization blades. include sweep angle blade γ , regular axial pitch p and circumferential angular offset α . evaluate mass flow rate Lacey...

A GMAW additive manufacturing process is performed with H08Mn2Si wire to fabricate a cube forming part. optical microscope was used observe the cross section aspect of part and structure mechanism has been analysed. The results demonstrate that presents characteristic macrostructure uniform microstructure changes circularly. circularly heating pattern surfacing in circular change preheating formed bead subsequent postheating are primary reason. Electromagnetic stirring effect longitudinal dc...