Increase In Number Of Cycles Research Articles

An electrical double-layer supercapacitor based on a biomass-activated charcoal electrode and ionic liquid with excellent charge-discharge cycle stability 

Supercapacitors that exhibit high power density and safety are emerging as alternative energy storage devices. The construction and performance of a supercapacitor using the ionic liquid, triethylammonium thiocyanate, as the electrolyte and biomass-activated charcoal films as the electrode are described. Enhancements in both energy and power density were observed even for 10,000 charge-discharge cycles. The fabricated supercapacitor with ionic liquid and activated charcoal-based electrodes showed an impressive specific capacitance retention of 142% even after 10,000 cycles at a scan rate of 500 mv s-1, which is attributed to the clearing of ion conducting pathways and enhanced charge transport with increasing temperature. Impedance analysis confirmed the reduction of resistive losses with increasing cycle numbers. The initial energy and power densities of the Electrical double-layer capacitance (EDLC) were 0.926 W h kg-1 and 5681 W kg-1, and they showed 42.2 % and 60.6 % increments after supercapacitors cycles. The study reveals low-cost biomass-based activated carbon electrodes and trimethylamine thiocyanate can be used to prepare supercapacitors with remarkable cycling performances.

Structural, morphological, and optical properties of CuO nanoblade-decorated TiO2 nanotubular photoelectrodes

Titania (TiO2) nanotubular photoelectrodes are a competitive component of titania-based photoelectrochemical water splitting systems. However, TiO2 actively absorbs light in the UV region, which limits its usefulness in solar water splitting, a fast-growing clean energy alternative. In this study, the structural, morphological and optical properties of CuO/TiO2 nanostructures on conductive transparent F-doped SnO2 (FTO) coated glass substrates are engineered for potential application in solar water splitting. The efficacy of a three-step anodization synthesis process to develop free-standing high-fidelity nanotubular TiO2 thin films (∼8μm) is demonstrated. CuO nanoblades were deposited on TiO2/FTO by a successive ionic layer adsorption reaction (SILAR). An increase in the precursor concentration and number of immersion cycles influenced the adsorption of CuO and the resultant red shift in the absorption range. SEM and TEM analyses confirm the formation of a heterostructure, with evidence of CuO nanostructures within the TiO2 nanotubular arrays and on the top of the tubes.

Investigation on fatigue performance and residual stress release mechanism of split sleeve cold expansion holes of heterogeneous 7050-T7451 aluminum alloy

7050-T7451 aluminum alloy is widely applied in aircraft structural components due to good properties, these components majority connected with hole structures. However, stress concentration occurs around structural holes during application, which leads to fatigue cracking and ultimately resulting in low fatigue performance of these parts. The residual stress generated by cold expansion can provide sufficient strength to prevent fatigue crack initiation. However, this protective effect is lost when the residual stress is released during fatigue. Consequently, it is crucial to investigate the release of residual stress in hole structures during the fatigue process. In this work, the residual stress release process and microstructure evolution under to different cyclic loads were investigated. The back stress induced by the heterogeneous structure on residual stress release and the effect of heterogeneous structure on crack propagation were discussed. The findings indicate that the back stress generated by GNDs of heterogeneous structures can resist the applied load in early stages, delay residual stress release. As the cycle number increases, potential mechanisms for the release of residual stress include dislocation annihilation, dislocation rearrangement, and dislocation shearing. The heterogeneous grain structure with high tortuosity and the deflection and branching of cracks can reduce the driving force of crack growth.

Investigation on the unsteady aerodynamic performance of the Drela AG 08 and Boeing B29 airfoils subjected to heaving motion

This article aims to investigate the unsteady flow characteristics of Drela AG08 and Boeing B29 airfoils when subjected to heaving motion. The influence of heave amplitude, heave frequency in terms of instantaneous force coefficients of the airfoil is investigated at Re = 5 × 104. Furthermore, the flow field investigations were carried out to analyze the Leading Edge Vortex (LEV) formation and its convection airfoil’s suction side. From the findings, a variation in the oscillation amplitude of force coefficients was observed and a non-sinusoidal behavior was also noticed. Additionally, a remarkable change in the instantaneous force coefficients (both qualitatively and quantitatively) is also observed with respect to the slight change in aforementioned parameters. A transition in the wake pattern from drag inducing to thrust producing is observed under certain conditions. It is observed that the flow separates at the leading edge by forming LEV on both airfoil’s suction side and pressure side. It is also noticed that whenever the flow departs the trailing edge, these vortices convect downstream of the airfoil and form alternating pattern of coherent vortices. With the increase in number of cycles, these vortices interfere with the previously shed vortices and affects the airfoil’s aerodynamic characteristics. From the investigations, it is observed that, by controlling the system parameters, the adverse effects of the LEV can be minimized.

Effects of Over-Sintering on Cyclic Calcination and Carbonization of Natural Limestone for CO2 Capture

To know the sustainable performance of calcium-based adsorbents is one of the important aspects to realize efficient and economical carbon capture, and to systematically study the properties of natural adsorbents is conducive to their industrialization. The cyclic calcination and carbonation characteristics of a typical natural limestone were investigated using a thermal gravimetric analyzer. Two kinds of over-sintering conditions were selected to emphatically study the cyclic separation of CO2 from limestones through prolonging the calcination time and increasing the calcination temperature. The results showed that the untimely end of the chemical reaction control stage caused by excessive sintering is the direct reason for the reduction in cyclic carbonation conversion, and the changes in surface morphology of calcined products due to pore collapse and fusion are the fundamental reasons for the reduction in cyclic carbonation conversion. The excessive sintering caused by extending the calcining time or increasing the calcining temperature has great inhibition on this cycle only; the inhibition decreases rapidly in subsequent cycles. In addition, SEM and BET–BJH tests further confirm the influence of the over-sintering phenomenon. With the further increase in cycle number, the early excessive sintering has certain stimulative effects on the subsequent carbonation reaction. It is expected to provide a reference for the subsequent research and development of natural calcium-based adsorbents.

Thermophysical-mechanical behaviors of hot dry granite subjected to thermal shock cycles and dynamic loadings

Exploring dynamic mechanical responses and failure behaviors of hot dry rock (HDR) is significant for geothermal exploitation and stability assessment. In this study, via the split Hopkinson pressure bar (SHPB) system, a series of dynamic compression tests were conducted on granite treated by cyclic thermal shocks at different temperatures. We analyzed the effects of cyclic thermal shock on the thermal-related physical and dynamic mechanical behaviors of granite. Specifically, the P-wave velocity, dynamic strength, and elastic modulus of the tested granite decrease with increasing temperature and cycle number, while porosity and peak strain increase. The degradation law of dynamic mechanical properties could be described by a cubic polynomial. Cyclic thermal shock promotes shear cracks propagation, causing dynamic failure mode of granite to transition from splitting to tensile-shear composite failure, accompanied by surface spalling and debris splashing. Moreover, the thermal shock damage evolution and coupled failure mechanism of tested granite are discussed. The evolution of thermal shock damage with thermal shock cycle numbers shows an obvious S-shaped surface, featured by an exponential correlation with dynamic mechanical parameters. In addition, with increasing thermal shock temperature and cycles, granite mineral species barely change, but the length and width of thermal cracks increase significantly. The non-uniform expansion of minerals, thermal shock-induced cracking, and water-rock interaction are primary factors for deteriorating dynamic mechanical properties of granite under cyclic thermal shock.

Effects of heating rate and deposition cycle on the structural, optical, and photoelectrocatalytic properties of electrodeposited hematite films

In this research, electrodeposited hematite films were prepared at voltammetry deposition cycles of 60 and calcined at 550 °C in a furnace after ramping the temperature at the rates of 2 °C/min, 10 °C/min, 35 °C/min, and rapid heating of about 100 °C/min. Additional samples were fabricated at deposition cycles of 15, 30, and 80, and also calcined at 550⁰C at a heating rate of 10⁰C/min. The impact of heating rate and deposition cycle number variations on the structural, optical, and photoelectrocatalytic (PEC) properties of the hematite films were assessed. All the films' X-ray diffraction (XRD) measurements showed strong peaks at the lattice planes (104) and (110), verifying hematite's rhombohedral crystal structure. The films prepared at the heating rate of 10⁰C/min boosted the crystallization of the films by 47.2 % relative to the ones prepared at 2⁰C/min. An increase in the deposition cycle number resulted in increasing film thickness and the sample’s crystallization. An indirect bandgap of 1.94–2.1 eV was estimated for the samples, with the least value obtained for the films treated at the heating rate of 10⁰/min and deposition cycles of 60. The same samples also yielded the largest photocurrent density of 26.2 μA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), while the photoanodes fabricated at 2 °C/min exhibited the lowest photo-activity. The enhanced photocurrent observed for the films has been associated with high crystallinity, improved photon absorption, reduced flatband potential, and increased charge separation at the film’s surface. This research underscores the importance of optimizing both the heating rate and deposition cycle numbers in the fabrication of electrodeposited photoelectrodes for PEC applications.

Study on the Deformation Behavior of Two Phases during the Low Cycle Fatigue of UNS S32750 Duplex Stainless Steel.

In this paper, the deformation behavior of UNS S32750 (S32750) duplex stainless steel during low cycle fatigue was studied by controlling the number of cycles. The microstructure of the specimens under different cycles was characterized by optical microscope (OM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM). The microhardness of the two phases was measured by a digital microhardness instrument. The results showed that the microhardness of ferrite increases significantly after the first 4000 cycles, while the austenite shows a higher strain hardening rate after fatigue fracture, and the microhardness of ferrite and austenite increases by 23 HV and 87 HV, respectively. The two-phase kernel average misorientation (KAM) diagram showed that the continuous accumulation of plastic deformation easily leads to the initiation of cracks inside the austenite and at the phase boundaries. The evolution of dislocation morphology in the two phases was obviously different. With the increase in cycle number, the dislocation in ferrite gradually transforms from dislocation bundles and a dislocation array to a sub-grain structure, while the dislocation in austenite gradually develops from dipole array to an ordered Taylor lattice network structure.

Thermal-mechanical modelling on cumulative freeze-thaw deformation of porous rock in elastoplastic state based on Drucker-Prager criterion considering dilatancy

The comprehensive understanding of freeze-thaw (F-T) deterioration and deformation properties of rock is a critical basis for frost damage prevention on cold regional rock engineering. In freezing process, plastic strain generates in rock when the stress induced by pore ice pressure (PIP) becomes higher than yield strength, and unrecoverable deformation accumulates in rock under multiple F-T cycles. Therefore, this study presents a thermal-mechanical modelling on cumulative F-T deformation of rock under cyclic F-T action. In the modelling of mechanical action, the microporomechanics theory is applied with a spherical element model in the derivation of equilibrium equations of rock, and the Drucker-Prager criterion is utilized with dilatancy effect of rock considered to describe unrecoverable plastic deformation cumulated in rock under multiple F-T cycles. The thermal process is modelled with unfrozen water content and latent heat accounted. The proposed thermal-mechanical modelling method is validated based on experiments and numerical simulations of F-T deformation of sandstone, and it is able to simulate the temperature and F-T deformation of rock in acceptable precision. The numerical distributions of temperature, PIP, maximum principal strain and displacement are exhibited and show that the plastic region begins to develop in rock matrix with PIP exceeding the elastoplastic critical pressure when temperature drops to about −2 °C and grows rapidly when temperature drops from −2 to −6 °C. Several F-T cycles later, large unrecoverable plastic strain remains in sandstone though PIP dissipates after thawing. The cumulative F-T deformation, porosity increment and maximum of plastic volume ratio are much greater under condition with freezing temperature of −20 °C, compared with condition −10 °C. Besides, as cycle number increases, the plastic volume ratio becomes smaller and its decrease rate attenuates.

The mechanical responses of SiC-coated carbon-bonded carbon fiber composites under quasi-static cyclic compressive loading

SiC-coated carbon-bonded carbon fiber composites (CBCFs), serving as novel thermal protection materials for hypersonic vehicles, are manufactured to investigate their mechanical properties concerning reusability. Comprehensive analyses are performed on their microstructures, including the fiber arrangement and the morphology of individual fibers and interconnecting bonds. The results demonstrate that SiC-coated CBCFs exhibit higher elastic moduli and strengths in both typical directions compared to bare CBCFs. To evaluate their durability in repeated use scenarios, a series of quasi-static uniaxial cyclic compressive experiments are conducted with emphasis on the variations of deformation recovery, load bearing and energy dissipation. The results indicate that SiC-coated CBCFs exhibit stable deformation recovery ability in the OP direction after the 25th cycle, with a decelerating decline in their load-bearing capacity observed over subsequent cycles. The energy loss coefficient initially decreases with increasing cycle number, and higher compression loads enlarge the amount of energy that is dissipated in the first cycle. These insights elucidate critical correlations between the mechanical properties of SiC-coated CBCFs and the number of compressive cycles, contributing to the optimization of their practical utilization in reusable scenarios.

Deterioration mechanisms of tuff with surface fractures under freeze–thaw cycles

In practical engineering, the development of surface cracks is one of the most important reasons for the destruction of the rock mass, and the development of complex morphology fractures on the rock mass surface significantly influences rock mass mechanics. This paper addresses the freeze–thaw damage issue in rock mass containing surface fractures in cold regions. Tuffs and a control group are selected as research samples, with the control group being prefabricated surface jointed specimens with an inclination angle of 70° and a fracture depth ratio d (crack depth) /t (sample width) of 0.26. The study analyzes the mass, wave velocity loss, macro-microcosmic fracture damage morphology, and mechanical properties of the two specimen groups through laboratory freeze–thaw cycle tests, uniaxial compression tests, and scanning electron microscopy examinations. The results show an overall decrease in mass, wave velocity, and uniaxial compressive strength as the cycle number increases, with the prefabricated jointed group samples showing more significant changes. However, the two specimen groups exhibit different macroscopic failure fracture states. In addition, scanning electron microscopy images illustrate that after freeze–thaw cycles, the large rock mass particles break into smaller fragments, resulting in looser particle arrangements and a transition from initial surface cementation to point contact., which weakens the compressive strength of the rock mass. The paper also explains the mechanism of the diminishing impact of freeze–thaw cycles on the strength of the rock mass after a certain number of cycles. The research outcomes hold significant reference value for engineering construction in cold regions.

Effect of wet-dry cycle on triaxial mechanical properties and constitutive models of solid waste cemented backfill

As the environmental requirements of underground mine backfilling processes have been promoted, solid waste cemented backfilling (SWCB) technology is widely exploited in goaf backfilling. Due to the groundwater circulation and geothermal drying effects, the SWCB is often exposed to the cycle period of wetting and drying state. To study the influence of wet-dry state transformation on the mechanical properties of SWCB, a series of triaxial compression tests were carried out on SWCB specimens treated with wet-dry cycle. As the cycle numbers increased, first, mass-loss behavior occurred and then hydration damage gradually accumulated in the SWCB specimen, where the maximum mass loss rate (Rw-d) was 7 %. The triaxial compressive strength (TCS) and elastic modulus of SWCB increased with the increase in confining pressure but decreased with the increase in cycle numbers. In low cycle numbers, the wet-dry cycle treatment did not damage the skeleton structure, and the SWCB specimen could still bear external load after failure. A constitutive model considering residual strength was established to describe the stress state and failure process of SWCB specimens. In high cycle numbers, hydration damage occurred and was widely distributed in the SWCB specimen. A rheology constitutive model was established to reflect the stress-strain relationship and flow failure characteristic. From the scanning electron microscopy (SEM) results after SWCB specimen failure, main cracks and many partial microcracks appeared in the low and high cycle numbers, which verified the applicability for two constitutive models. Aiming at the negative effect of wet-dry cycle on the mechanical properties of SWCB, isolating water source and protecting SWCB were proposed to prevent and control the large deformation of SWCB and surface subsidence induced by rheological behavior.

Interpretation and reporting considerations of low-level DNA profiles following MinElute® purification of PowerPlex® 21 amplified products

The generation of high-quality DNA profiles from trace amounts of DNA continues to be an issue in forensic casework. Several methods have been proposed over the years to increase recovery rates for low input DNA, including purification of PCR products, an increase in PCR cycle numbers and increasing injection time or voltage during electrophoresis. In this study, the characteristics of DNA profiles generated using QIAGEN MinElute® purification of Promega PowerPlex® 21 amplified products for low DNA input samples, ranging from 80 pg down to 4 pg, were evaluated. MinElute® purification was found to be a simple, effective and time efficient method, which can greatly improve the resolution of amplified PCR products, recovering 100% of donor concordant alleles from as little 16 pg of input template DNA and generating sufficient allelic information for interpretation from as low as 4 pg inputs. However, as is commonly observed with low template DNA samples, the results exhibited extensive disparity in the effects of stochastic variation in amplification, including increased heterozygote peak height imbalance, stutter ratios and instances of allelic drop-in and drop-out, both within and between replicates. As such, it is important that the extent and variability of these stochastic effects are appropriately incorporated in the development of robust profile interpretation guidelines for DNA profiles generated from purified PCR products.

Evaluation of pulp tissue dissolution capacity through different sodium hypochlorite agitation protocols.

This ex vivo study aimed to assess the dissolving capacity of 2.5% sodium hypochlorite using eight agitation protocols within swine pulp tissue. Twelve lower first premolars were prepared and split into the fragments with a groove housing porcine dental pulp. Groups were assigned based on agitation systems: manual, passive ultrasonic, Easy Clean and XP-Endo Finisher. Two agitation time protocols were applied: One min (3 s × 20 s cycles) and 2 min (6 s × 20 s cycles). Wilcoxon Mann-Whitney U test was used to compare the groups. Both time frames demonstrated superior results compared to manual group (P > 0.5). However, in the two min groups, no significant differences were observed among the other protocols (P < 0.5). Intriguingly, increasing cycle numbers significantly improved results within each group (P > 0.5). Extending the chemical agitation time during final irrigation enhances tissue removal, regardless of the irrigation protocol employed.

Experimental study on the influence of principal stress axes rotation on sand mechanical behavior and non-coaxiality effects

The soil around the foundations of offshore engineering experienced the principal stress axes rotation caused by the wave loadings. To investigate the influence of the principal stress axes rotation on the soil stress-strain relationship, a series of pure principal stress axes rotation tests under drained/undrained conditions were carried out with a hollow cylinder apparatus. The undrained test results show that the deviatoric stress, relative density, and starting point of rotation affect the mechanical properties of sand. Through the analysis of pore water pressure accumulation in the 1st cycle, it was observed that more pore pressure accumulates in Quadrants II and III, while relatively less accumulates in Quadrants I and IV. Under drained and undrained conditions, the non-coaxial behavior of the soil differs. The non-coaxiality can be significantly observed in the drained test, and the direction of strain increment tends to the stress increment direction when the cycle number increases.

Experimental study on response and precursor of pressure stimulated currents of combined coal-rock under cycling stress

The coal-rock combination body is prone to rock burst and surface subsidence under loading, and adopting effective monitoring methods are valuable. In this paper, cyclic loading and unloading (CLU) tests were conducted to investigate the response and precursor of pressure stimulated currents (PSCs) in coal-rock combination samples. The results indicate that the PSCs of the coal-rock combination samples have good response characteristics to stress. Furthermore, the PSCs between the two components are significantly larger and more stable than those of the coal body, which can clearly reflect the failure under a progressive failure mechanism and are related to the difference in the resistivities and microstructures of the components. During the CLU tests, the PSCs of each cycle are well fitted by the Gaussian distribution and have a memory effect. During the loading or unloading process of each cycle, the variation in PSCs with stress conforms to the power function relationship with exponent k. As the cycle number increases, the rates of increase in PSC under stress are gradually weakened, and the indexes of PSCs including exponent k increase or decrease sharply first and then remain stable or even decrease, which is due to the loading history. The stable state of these indexes with obvious inflection points in later cycles of CLU tests can be considered a precursor of coal-rock failure. The PSC flow direction between the two components is exactly opposite to that in the coal body. The results provide new ideas for the monitoring and prediction of coal-rock combination body failure, which is helpful for the prevention of geological disasters in mines.

Biocomposite Anchors Have Greater Yield Load and Energy Compared With All-Suture Anchors in an In Vitro Ovine Infraspinatus Tendon Repair Model

PurposeTo compare tensile fatigue and strength measures of biocomposite and all-suture anchors in an ovine humerus-infraspinatus tendon model of rotator cuff repair. MethodsInfraspinatus tendons on adult ovine humeri were sharply transected at the insertion. One of each pair was randomly assigned for fixation with two biocomposite or all-suture anchors. Constructs were tested with 200 cycles of 20-70 N tensile load and gap formation was measured at the incised tendon end every 50 cycles. They were subsequently tested to failure. Outcome measures including fatigue stiffness, hysteresis, creep and gap formation, and tensile stiffness, and yield and failure displacement, load, and energy were compared between anchors. ResultsBiocomposite anchors had higher yield load (134.1 ± 6.5 N, p<.01) and energy (228.6 ± 85.7 J, p<.03) than all-suture anchors (104.7 ± 6.5 N, 169.8 ± 85.7 J). Fatigue properties were not different between anchors, but stiffness and gap formation increased and hysteresis and creep decreased significantly with increasing cycle number. ConclusionsWhile the yield displacement of both anchors was within the range of clinical failure, the tensile yield load and energy of ovine infraspinatus tendons secured to the humerus with two single-loaded all-suture anchors in a single row were significantly lower than those secured with two biocomposite anchors in the same configuration. Clinical RelevanceIt is important to understand the biomechanical properties for selecting anchors for rotator cuff repair. A direct comparison of fatigue testing followed by failure strength of infraspinatus tendon fixation with all-suture and biocomposite anchors could help guide anchor selection and post-operative mobility recommendations.

Deuterium retention in cyclic transient heat loaded tungsten with increasing cycle numbers

Surface damage and microscopic defect evolution of tungsten (W) armor under transient heat loads are key factors for fuel retention in fusion reactors. In this work, experiments were conducted to investigate the effects of cyclic thermal shocks on deuterium (D) retention and surface blistering in W. Thermal shock experiments were conducted on recrystallized W using an electron beam with a power density of 0.15 GW m−2 across 100–1500 cycles, followed by D plasma exposure with high-fluence (∼1 × 1026 D m−2). The results demonstrate that samples subjected to 500 and 1500 cycles exhibit a significant presence of sub-grains within 90 μm. Notably, the inhibition of blistering induced by thermal shock leads to a substantial reduction in D retention (5.45 × 1019 D m−2) at lower cycle numbers (100 cycles) compared to the reference sample (2.35 × 1020 D m−2) which was only exposed to D plasma. When cycle numbers increase to 500 and 1500, D retention reaches 1.98 × 1020 D m−2 and 4.56 × 1020 D m−2, respectively. Based on the tritium migration analysis program, we propose that total D retention is a consequence of the competition between defects reduced by thermal shock-induced suppression of blistering and defects generated by plastic deformation induced by thermal stress. D retention initially decreases with the increase in cycle numbers, followed by a subsequent rise, with the inflection point slightly higher than 500 cycles. Additionally, due to the extensive scope of thermal stress, an escalated exposure period will result in substantial D captured by heat-induced defects, consequently intensifying the D retention. Whether there exists an upper limit to D retention induced by the increasing thermal shock cycles necessitates further experimental analysis. Nonetheless, it is evident that thermal shock significantly contributes to D retention within a profoundly deep bulk region under high cycles.

Sulfur loads under high temperature on the surface of C/SnO2 to enhance first platform capacity of lithium-sulfur batteries

Polysulfides are easily dissolved during the redox reaction process of Li-S batteries, which may be severe when current density and cycle number increase. Increasing capacity of the first platform effectively is beneficial for improving cycling stability. Physical sulfur loads are benefit for achieving high-capacity storage. However, the influence of composite electrodes with sulfur loads under high temperature on cycling stability of the first platform capacity has not been studied. Sulfur particles are loaded on the surface of C/SnO2 under high temperature in this work. C/SnO2/S and C/SnS/S composite electrodes are obtained by controlling sulfur contents. Results show that C/SnS/S composite electrodes display better cycling stability (1161 mAh⋅g−1) than C/SnO2/S composite electrodes at 1C after 100 cycles, especially in P1 platforms (724 mAh⋅g−1). When cycling number increases to 1000, C/SnS/S composite electrodes still possess good cycling stability (274.8 mAh⋅g−1) at 1C. Good cycling stability is ascribed to strong surface activities of sulfur in SnS and rapid electron transportation abilities during the cycling process. Studying sulfur-loading methods under high temperature is beneficial for obtaining high cycling performance composite electrodes for lithium-sulfur batteries.

Bearing and deformation characteristics of monopile foundation under monotonic and cyclic horizontal loads.

The bearing and deformation characteristics of monopile foundation under the monotonic and cyclic loads are key factors to consider in the design of the transmission tower structure or offshore wind energy converters. The model tests and numerical simulations of monopile foundation under monotonic and cyclic horizontal loads were performed in sand to explore the bearing characteristics and the deformation characteristics of pile. The potentially affected factors including loading height, relative density of soil, displacement amplitude were analyzed. The results show that with the loading height varies from 1D to 4D, the horizontal static bearing capacity of the pile under different the soil relative density decreased by 1.63-1.9 times, and the peak bending moment increased by 22.9%-36.8%. Under the cyclic loads, the peak load on the pile top increased by 31.7%-56.1% for each 1 mm increase in displacement amplitude. The stiffness of soil around pile varies as the number of cycles increases with the development trend of decreases first and then increases gradually. As the horizontal load and cycle number increase, the range of the displacement of soil extends towards the bottom of pile, until it covers the entire lower part of the model.