Increase In Penetration Depth Research Articles

A study for gamma-ray attenuation performances of barite filled polymer composites

In this study, radiation protection efficiency (RPE) for the coded as UP-Ba0, UP-Ba25, UP-Ba50, UP-Ba75 and UP-Ba100 at different sample thicknesses, total mass attenuation coefficient (μ/ρ), linear attenuation coefficients (μ), half value layers (HVL), tenth value layers (TVL), mean free paths (MFP), effective atomic numbers (Zeff) and effective electron densities (NE) were determined at various gamma energies between 59.5 and 1408.0 keV. With the help of the geometric progression (G-P) fitting method, the energy absorption build-up factor (EABF) and exposure build-up factor (EBF) values were calculated in the energy range from 0.015 MeV to 15 MeV for the produced composites. HPGe detector and eight radioactive sources (241Am, 152Eu, 137Cs, 133Ba, 60Co, 57Co, 54Mn and 22Na) were utilized in the experiment. Experimental results were compared with theoretical calculations and it has been observed that there is a good agreement between theoretical and experimental results. It was observed that RPE, μ/ρ, μ, Zeff and NE parameters increased with increasing barite amount and decreased with increasing energy, while the opposite situation was observed in HVL, TVL and MFP parameters. EABF and EBF values increase with increasing penetration depth. As a result, UP-Ba100 is a good radiation absorber according to the other studied barite filled polymer composites.

Research of jacked pile penetration test based on airbag loading

In view of the problem that the model test of pile jacking cannot reproduce the soil's self-gravity and thus cannot truly reflect the pile jacking force, this paper developed an airbag loading system. The airbag is used to pressurize and simulate the overburden soil weight. The method of subsection pile jacking and coupling is ingenuously adopted to achieve long pile penetration. Because the airbag and pressure can be controlled well, it is convenient to simulate the cohesive soil foundation. The size of the model pile used in the test is larger than that of the usual centrifugal model test pile, so it belongs to large scale model test. The experimental results using this system show that the pile jacking force increases with the increase of penetration depth. The degradation of pile lateral resistance has little impact on pile jacking force. After modification based on the degradation theory of pile lateral resistance, the overall variation law of pile lateral resistance is good, and the difference value generated at the joint of pile segments is basically 0. With the increasing of pile depth, the pile lateral resistance is gradually exerted. The pile end resistance fluctuates with the depth, and accounts for a relatively high proportion of pile jacked force, which is maintained above 50%. The method of pile jacking with airbag loading in this paper provides a new idea for the study of the penetration characteristics of jacked pile.

Quantitative tumor depth determination using dual wavelength excitation fluorescence.

Quantifying solid tumor margins with fluorescence-guided surgery approaches is a challenge, particularly when using near infrared (NIR) wavelengths due to increased penetration depths. An NIR dual wavelength excitation fluorescence (DWEF) approach was developed that capitalizes on the wavelength-dependent attenuation of light in tissue to determine fluorophore depth. A portable dual wavelength excitation fluorescence imaging system was built and tested in parallel with an NIR tumor-targeting fluorophore in tissue mimicking phantoms, chicken tissue, and in vivo mouse models of breast cancer. The system showed high accuracy in all experiments. The low cost and simplicity of this approach make it ideal for clinical use.

Comparison Study on Coarseness Index and Maximum Diameter of Rock Fragments by Linear Cutting Tests

Rock fragments obtained by excavation can provide information for evaluating the excavation efficiency, for which the coarseness index (CI) and particle size parameters (d50, dMPS, and d′) are used. However, CI depends on the number and size of the sieves used, and the particle size parameters require mathematical calculations. In this study, the maximum diameter (dmax) of rock fragments was used as an indicator of the excavation efficiency. Linear cutting tests were performed and the rock fragments were sieved to obtain the CI and dmax. The relationship between dmax and CI was similar to that between other particle parameters and CI. dmax and CI increased with increasing penetration depth and spacing, but dmax followed a linear relationship, and CI demonstrated a power relationship. Both dmax and CI reached their maximum values at a specific ratio of spacing to penetration depth (s/p ratio) and were not affected by subsequent increases in s/p. The cutting force and volume had positive relationships with dmax and CI, linear with dmax and exponential with CI, whereas the specific energy (SE) had an inverse relationship, showing exponential and linear relationships with dmax and CI, respectively. When dmax was larger than a certain value, SE converged to a constant value. This study confirmed that dmax has an advantage over CI in determining excavation efficiency.

TeO2 for enhancing structural, mechanical, optical, gamma and neutron radiation shielding performance of bismuth borosilicate glasses

The synthesized 12Bi2O3– 8BaO–12ZnO-0.5CeO2-17.5SiO2- (50-x) B2O3- xTeO2 glasses with x = 0, 10, 20, 30 and 40 mol% (coded BiTe-0 to BiTe-40) were investigated in terms of physical, structural, optical and mechanical properties to examine the influence of CeO2 and TeO2 on the heavy metal oxide (HMO) borosilicate network. Density values increased continuously with increasing TeO2 concentration with BiTe-40 glass exhibiting maximum value of 5.0875 gcm−3. This property helped in enhancement of refractive index values from 1.769 for BiTe-0 to 1.942 for BiTe-40. Fourier transform infrared (FTIR) analysis of studied glasses revealed the presence of additional small peak at 683 cm−1 in BiTe-30 and BiTe-40 which confirmed the formation of stable TeO4 units in the glass network. The deep brown colour of the glass existing due to bismuth's presence was nullified by CeO2 and TeO2 additives which improved transparency of the glass. Urbach analysis of these glasses led to optical bandgap variation between 3.27 eV and 2.73 eV for 0–40 mol% TeO2 concentration. Makishima and Mackenzie model was utilized for evaluation of elastic property of the glasses, and Poisson's ratio ranging between 1.935 and 1.953 was obtained. Vickers micro-indentation test on the current glasses revealed decreasing microhardness from 4.116 to 4.076 GPa with TeO2 variation from 0 to 40 mol% at 9.8 N load. Gamma radiation shielding parameters were determined using Phy-X/PSD software and it was found that BiTe-40 glass produce maximum MAC (mass attenuation co-efficient) values in high photon energy region 3.5–15 MeV. The present article also contains a detailed emphasis on behaviour of gamma radiation build-up factors at different incident photon energy and TeO2 concentration. The increasing trend of exposure build up factor (EBF) was seen with increasing penetration depth inside the samples at all energies, indicating that glasses of larger thickness improve the escape probability of photons. Meanwhile, fast neutron removal cross-section (FNRCS) was highest for BiTe-10 sample (0.10118 cm−1) which also surpassed the value of ordinary concrete (0.093 cm−1). Overall, the present glass system bested other conventional shields available commercially in terms of gamma and neutron radiation shielding effectiveness.

Effect of grinding damage on cutting force and ductile machining during single grain scratching of monocrystalline silicon

Understanding the initiating and suppression mechanisms of existing defects are the key to optimizing the ultra-precision grinding process of hard and brittle materials. This paper discusses the effects of grinding damage on material removal mechanism from the perspectives of residual scratch depth, scratch morphology and normal scratching force, through conducting the contrast variable-depth nano-scratch experiment on polished and ground monocrystalline silicon and establishing the single grain scratching Smoothed Particle Hydrodynamics (SPH) model. The experimental and simulation results show that radial crack on ground silicon surface is almost invisible due to the existence of grinding marks, which indicates that it is difficult to judge the ductile brittle transition (DBT) point by the traditional method of observing cracks. With the increase of penetration depth, pop-in will occur in the residual scratch depth of polished and ground silicon, indicating that the material removal mode has transformed, which provides an important basis for judging the DBT point. The DBT critical normal scratching force (38.93 mN) and residual scratch depth (−0.14 μm) of ground silicon are much higher than those of polished silicon, implying ground silicon is easier to achieve ductile processing. Meanwhile, when the penetration depth is the same, compared to polished silicon, the normal scratching force of ground silicon is generally larger. Finally, a single grain scratching SPH model of pre-stressed silicon is established. And the simulated phenomenon and conclusions are consistent with the experiment, which proves that the surface compressive stress is an important factor that causes the removal characteristics of ground silicon to be different from polished silicon. This study provides a theoretical basis for understanding the ultra-precision grinding removal mechanism of hard and brittle materials.

Scratch-induced deformation and damage behavior of doped diamond-like carbon films under progressive normal load of Vickers indenter

Microscratch test was conducted on four different diamond-like carbon (DLC) films by Vickers indenter to study the scratch resistance of films under progressive normal load linearly increasing from 5 mN to 15 N. With the increase of normal load, penetration depth, lateral force, residual and contact scratch widths increase nonlinearly; scratch hardness and lateral hardness decrease nonlinearly; scratch friction coefficient increases under small loads, and then tends to be a constant under large loads. DLC-H has the smallest scratch friction coefficient among the four films, and different targets have little effect on scratch friction coefficient. DLC-Si and DLC-Cr have almost the same scratch resistance (or penetration depth), and larger than that of DLC, whose scratch resistance is almost the same as that of DLC-H. Fracture toughness was obtained by scratch-based methodologies: the additional Si or Cr target can enhance fracture properties of DLC film-steel substrate systems, whereas C4H10 can harm fracture properties. Fracture toughness of DLC-Si (about 17 MPa·m1/2) was larger than that of DLC-Cr (about 15 MPa·m1/2) with the large values of fracture toughness obtained under penetration depth larger than film thickness attributed to substrate effect.

Increase in rock drill penetration depth

The application range of remote drilling machines is described. The common shortage of these machines is the dependence of the blow energy transfer to the bottomhole on the bottomhole depth. Aimed to reduce the influence of this factor, it is proposed to use the mixed-type method of drilling with a downhole rock drill to be placed directly at the bottomhole. The key element of this method is a small-size DTH rock drill. The layout of the rock drill and its prototype testing results are presented.

Secondary electron emission of Al<sub>2</sub>O<sub>3</sub> and MgO nanofilms fabricated by atomic layer deposition

<p indent="0mm">Electron multiplier devices are widely applied in many electronic instruments like mass spectrometers and atomic clocks. It is considerably crucial for a multiplier to possess a high electron gain, and this index can be directly determined by secondary electron yield (SEY) of the dynodes. Al₂O₃ and MgO possess a relatively high SEY level among majority of dynode materials, and their film products are excellent dynode candidates. Whereas, for some multipliers like microchannel plate (MCP), only an ultrathin film of several nanometers is allowed to be coated onto the inner wall of the micro channels to avoid the variation of the channel diameter. Therefore, SEY characteristics of the ultrathin films are necessary to be figured out. Here, by using the technology of atomic layer deposition, 7 groups of ultrathin Al₂O₃ and MgO nanofilms with increase thickness (1, 3, 5, 7, 10, 30, and <sc>50 nm)</sc> are fabricated on silicon (Si) substrates. As well as, 5 groups of Al₂O₃ nanofilms (1, 2, 3, 4, and <sc>20 nm)</sc> are deposited on MgO film <sc>(20 nm)</sc> substrate. Surface composition, morphology, film thickness, and SEY have been characterized in detail. Via the experiments, it is found that SEY of the Al₂O₃/Si and MgO/Si samples largely depends on the film thickness, namely, SEY increases obviously as the film thickness rises, meanwhile, the increment of SEY decreases gradually. The SEY tendency indicates that the effect of top film on SEY becomes enhanced, and the influence of bottom substrate on SEY becomes weakened. When the film thickness increases beyond <sc>30 nm,</sc> SEY increment approaches to 0, and SEY tends to be saturated. This phenomenon demonstrates that the penetration depth of incident electrons is less than the film thickness under the circumstances. To interpret the experimental results, the SEE semi-physical theory developed for double layer structures is utilized. The calculation results indicate that the film thickness has a remarkable impact on SEY, especially when the incident energy becomes lower and the film becomes thicker, the results also reveal that the dielectric surface film possesses a great ability to modulate the surface SEY. However, SEY becomes less dependent on film thickness as the incident energy increases, and it results from the increase of penetration depth for the incident electrons. This work reveals the mechanism of the SEE characteristics for ultrathin Al₂O₃ and MgO nanofilms, which is of great significance for the subsequent research on the use of nanoscale high SEY dielectric films as the SEE functional layer in electron multipliers.

Using suction in back-bleeding conditions increases cement penetration without the need for a tourniquet

BackgroundThe majority of total knee arthroplasties are performed with a tourniquet as it is perceived this gives rise to superior cement fixation. Tourniquets, however, have been associated with increased pain, post-operative swelling, and reduced knee range of movement which can all detrimentally impact patient recovery. This laboratory-based study aimed to assess if it is possible to achieve equivalent (or even enhanced) cementation without a tourniquet using a novel suction device. MethodsCement penetration was compared between conditions simulating bone with back-bleeding with and without the use of suction in open-cell rigid foam tibia models and porcine specimens. Suction was applied via a urinary catheter inserted into the tibial recess created for the implant's stem. Cement penetration depth was measured from micro-CT scans. The pull-off strength of cemented tibial implant analogues in porcine specimens with and without suction was also assessed. ResultsSuction gave rise to a significant (p = 0.028) increase in cement penetration depth in both the rigid foam, 5.4 – 6.6 mm, and porcine specimens, 0.7 – 1.0 mm. A non-significant increase in implant pull-off strength was also observed. ConclusionSuction during cementation in a back-bleeding model resulted in significantly greater cement penetration depth. Using suction surgeons can avoid potential disadvantages of tourniquet use without compromising cementation.

Seasonal Impact on 3D GPR Performance for Surveying Yedoma Ice Complex Deposits

Ground-penetrating radar (GPR) is a popular geophysical method for imaging subsurface structures with a resolution at decimeter scale, which is based on the emission, propagation, and reflection of electromagnetic waves. GPR surveys for imaging the cryosphere benefit from the typically highly resistive conditions in frozen ground, resulting in low electromagnetic attenuation and, thus, an increased penetration depth. In permafrost environments, seasonal changes might affect not only GPR performance in terms of vertical resolution, attenuation, and penetration depth, but also regarding the general complexity of data (e.g., due to multiple reflections at thaw boundaries). The experimental setup of our study comparing seasonal differences of summertime thawed and winter- and springtime frozen active layer conditions above ice-rich permafrost allows for estimating advantages and disadvantages of both scenarios. Our results demonstrate major differences in the data and the final GPR image and, thus, will help in future studies to decide about particular survey seasons based on the GPR potential for non-invasive and high-resolution investigations of permafrost properties.

Development mechanism of aging depth of bitumen with increasing UV aging time

The UV aging of bitumen has a significant influence on the pavement service life, therefore, the research on UV aging has attracted increasing attention recently. It is known that the aging of bituminous pavements does not occur instantly through the full depth, instead, the aging depth of the bitumen increases gradually with the increasing aging time. The limitation of the research is that the development mechanism of the aging depth of bitumen is not clearly known. Various thicknesses of bituminous membranes were prepared and the UV light transmission and absorption properties of bituminous membranes were investigated by UV–visible spectrophotometric, aiming to determine the penetration depth of UV light in bitumen after UV aging. It is concluded that, for the same bituminous membrane, the transmittance of UV light increases with the increase of the light wavelength; while the transmittance of UV light decreases significantly with the increase of bituminous membrane thickness. The penetration depth of UV light in bitumen increases gradually with increasing UV aging time. The relationship between UV light penetration depth in bitumen and aging depth of bitumen was analyzed, and UV aging models of three parts of bitumen were established to reveal the development mechanism of the UV aging depth of bitumen during UV aging. The increasing aging depth of bitumen is due to the increase of UV light penetration depth in bitumen, and the diffusion action of aging products from surface bitumen to deeper bitumen. During the UV aging, the bitumen actually comprises three parts, namely, the surface direct aging part (UV light can reach), the deeper diffusion aging part (aged by the diffusion action) and the internal unaged part (UV light and diffusion action can not affect).

Breakage effect of calcareous sand on pile tip resistance and the surrounding soil stress

Due to the irregular shape, high porosity and fragility of calcareous sand particles, the construction of reef engineering is seriously affected, and the application of pile foundation engineering technology in calcareous sand stratum is also faced with great challenges. Based on the discrete element method (DEM), the pile installation process in the fractured calcareous sand stratum and non-fractured silica sand stratum are simulated, respectively, and the influence of particle breakage of calcareous sand on soil stress around the pile and pile tip resistance are discussed. The results show that the particle contact has no obvious dominant direction, and the particle breakage has little contribution on the variation of the particle contact normal directions while has great influence on the number of contact normals and the magnitude of contact normal force which is more uniform after particle breakage. The vertical and horizontal stresses in calcareous sand stratum are obviously lower than that in siliceous sand stratum. With the increase of the pile penetration depth, the number of crushing particles increases gradually. The particle breakage only can be found within the range of 3 times of pile diameter at the bottom of the pile and also within the range of 1 time of pile diameter around the pile. The effect of particle breakage on pile tip resistance is mainly reflected in the later stage of pile sinking. In calcareous sand, when the pile tip resistance increases to a certain extent, particle breakage occurs and the stresses in the soil cannot continually increase. Therefore, the pile tip resistance fluctuates around a stable value (∼0.3MPa). This is the reason that the pile tip resistance in calcareous sand is far less than that in siliceous sand, which is prone to pile foundation failure.

Investigations Regarding the Addition of ZnO and Li2O-TiO2 to Phosphate-Tellurite Glasses: Structural, Chemical, and Mechanical Properties.

Phosphate and tellurite glasses can be used in optics, optoelectronics, magneto-optics, and nuclear and medical fields. Two series of phosphate-tellurite glasses, (50-x)ZnO-10Al2O3-40P2O5-xTeO2 and (40-x)Li2O-10Al2O3-5TiO2-45P2O5-xTeO2 (x = 5, 10), were synthesized by a non-conventional wet-route, and the mechanical properties as key performance measures for their application in optoelectronics were investigated. X-ray Diffraction (XRD) measurements revealed the vitreous nature of the investigated materials. Instrumented indentation tests allowed the calculation of hardness (H) and Young’s modulus (E) using the Oliver and Pharr model. The influence of increasing the TeO2 content, as well as the substitution of ZnO by Li2O-TiO2, on the variation of hardness, Young’s modulus, penetration depth (PD), and fracture toughness (FT) was evaluated in both series. As a general trend, there is a decrease in the hardness and Young’s modulus with increasing penetration depth. The addition of Li2O and TiO2 instead of ZnO leads to improved hardness and elastic modulus values. Regarding the H/E ratio, it was found that the samples with lower TeO2 content should be significantly more crack-resistant compared to the higher TeO2 content samples. The H3/E2 ratio, being lower than 0.01, revealed a poor resistance of these glasses to plastic deformation. At the same time, a decrease of the fracture toughness with increasing TeO2 content was noticed for each glass series. Based on dilatometry measurements, the thermal expansion coefficient as well as the characteristic temperatures of the glasses were measured. Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray analysis (FESEM-EDX) revealed a uniform distribution of the elements in the bulk samples. The mechanical properties of these vitreous materials are important in relation to their application as magneto-optical Faraday rotators in laser cavities.

Oxidation behavior of TiCr and TiMo alloys formed by low-energy pulsed electron beam impact

The titanium-based alloys with 2–3 at.% of chromium (TiCr) and molybdenum (TiMo) were produced on the top of titanium samples by means of the high-intense pulsed electron beam impact on the titanium with preliminary deposited Cr and Mo coatings. The TiCr and TiMo alloys were subjected to oxidation in open air atmosphere at temperature 600 °C. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy-disperse X-ray microanalysis (EDX) were used for structure and elemental composition determination in the samples. The analysis of oxygen depth profiles showed the increase in oxygen penetration depth in the case of TiCr alloy in comparable to pure titanium. The oxygen concentration corresponding to stoichiometry of the oxide phase TiO2 was found on the depth equaled to the thickness of the TiCr alloy that shows the enhancement of the diffusion of oxygen in the modified layer. The diffusion of oxygen at the temperature of 600 °C is enhanced by decomposition of the solid solutions based on bcc β-Ti phase with free chromium and molybdenum atoms releasing. The free molybdenum atoms take part in the stabilization of TiO2 anatase phase while the free chromium atoms form intermetallic compound TiCr2 preventing the sample from oxidation.

Effect of irradiation temperature on the nanoindentation behavior of P92 steel with thermomechanical treatment

The nanoindentation behavior of P92 steel with thermomechanical treatment under 3.5 MeV Fe13+ ion irradiation at room temperature, 400 and 700 °C was investigated. Pop-in behavior is observed for all the samples with and without irradiation at room temperature, while the temperature dependence of pop-in behavior is only observed in irradiated samples. The average load and penetration depth at the onset of pop-in increase as the irradiation temperature increases, in line with the results of the maximum shear stress. Irradiation induced hardening is exhibited for all irradiated samples, but there is a significant reduction in the hardness of sample irradiated at 700 °C in comparison to the samples irradiated at room temperature and 400 °C. The ratio of hardness to elastic modulus for all samples decreases with increasing penetration depth except for samples at 700 °C. With the increasing of irradiation temperature, the ratio of the irreversible work to the total work gradually decreases. In contrast, it increases for samples without irradiation.

CFD simulation of molten pool dynamic behavior on vertical-downward position in P-GMAW process

A three-dimensional numerical simulation was performed using computational fluid dynamics in the vertical-downward position. The molten pool dynamic behaviors play a significant role in determining the weld bead geometry. In the vertical-downward position, the penetration depth is not proportional to the heat input and the amount of filler metal supply. At a low welding speed (36 cm/min), gravity continuously pushes the molten pool toward the gravitational direction and causes swelling of the molten pool at the arc center, which in turn produces a cushion effect. The cushion effect absorbs the momentum transfer, resulting in shallow penetration with a large bead width and low dilution. The swelling of the molten pool at the arc center accelerates the forward flow. Then, necking of the molten pool bridge occurs. In contrast, a high welding speed (84 cm/min) causes a thin molten pool layer to form at the arc center and induces a strong downward flow as a result of the momentum transfer, which can be attributed to the increasing penetration depth and dilution. The microstructures of the weld metal and coarse grained heat-affected zone in the weld toe and weld root were analyzed.

Laboratory Tests on Open‐Close Pile Jacking and Load Bearing Characteristics in Saturated Clay Soil

The stress characteristics of the pile‐soil interface have an important influence on the effect and long‐term bearing capacity of jacked piles. In order to obtain the stress characteristics of the pile‐soil interface of the jacked pile in clay, the development law of pore water pressure and earth pressure for open‐ and closed‐end jacked piles during the pile jacking process was studied using indoor model tests based on a saturated soft clay foundation. Test results show that, during the pile jacking process, the excess pore water pressure, earth pressure, and effective earth pressure at the pile‐soil interface all increase gradually along penetration depth, and the increasing trend first increases linearly and then increases sharply at the pile end. The excess pore water pressure at the pile‐soil interface of an open‐end pile is smaller than that of a closed‐end pile. The earth pressure and effective earth pressure at the pile‐soil interface of the closed‐end pile show a “lateral pressure degradation,” and the degradation becomes more and more significant with increasing depth. The pile‐soil interface adhesion coefficient increases with increasing penetration depth, and the greater the adhesion coefficient is, the higher the tightness between the pile and soil will be. As a method of determining the interfacial tightness between the pile and soil, the adhesion coefficient is closely related to the excess pore water pressure and earth pressure generated during the pile jacking process and can accurately reflect the mechanical mechanism of pile jacking in saturated viscous soil. Results of this contribution can provide reference for theoretical research on the mechanical pile jacking mechanism in saturated viscous soil.

Brush grinding aluminum alloy mechanism of single steel wire based on finite element approach

In the process of surface treatment, steel wire brush can not only efficiently remove surface contaminants, such as deteriorated paint film and rust, but also increase the adhesive strength. However, the associated brush mechanics of material removal is still not clear. In order to reveal the brush mechanics of material removal, this paper assumed the tip of steel wire were ball–cone shaped, constructed contact force model, and calculated the brush grinding force under different process conditions based on finite element approach. The simulated results show that the brush grinding can be changed from plastic plowing to chip formation when the penetration depth is increased to 10 μm, then changed from chip formation to plastic plowing when the inclination angle is increased to 30°, respectively. The simulated value of brush force rises with the increasing penetration depth and inclination angle, which was consistent with the experimentally obtained values, and the relative errors are within 9%. The quantity of material removal increases with the ascending of penetration depth, and decreases with the ascending of inclination angle. This paper provides guidance to understand the mechanics of material removal, predict the brush grinding force, and contribute well to an automatic grinding control application.

The influence of gravity on granular impacts

Context. Impacts on small-body surfaces can occur naturally during cratering events or even strategically during carefully planned impact experiments, sampling maneuvers, and landing attempts. A proper interpretation of impact dynamics allows for a better understanding of the physical properties and the dynamical process of their regolith-covered surfaces and their general evolution. Aims. This work aims to first validate low-velocity, low-gravity impact simulations against experimental results, and then to discuss the observed collision behaviors in terms of a popular phenomenological collision model and a commonly referenced scaling relationship. Methods. We performed simulations using the soft-sphere discrete element method and two different codes, Chrono and pkdgrav. The simulations consist of a 10-cm-diameter spherical projectile impacting a bed of approximately 1-cm-diameter glass beads at collision velocities up to 1 m s−1. The impact simulations and experiments were conducted under terrestrial and low-gravity conditions, and the experimental results were used to calibrate the simulation parameters. Results. Both Chrono and pkdgrav succeed in replicating the terrestrial gravity impact experiments with high and comparable computational performance, allowing us to simulate impacts in other gravity conditions with confidence. Low-gravity impact simulations with Chrono show that the penetration depth and collision duration both increase when the gravity level decreases. However, the presented collision model and scaling relationship fail to describe the projectile’s behavior over the full range of impact cases. Conclusions. The impact simulations reveal that the penetration depth is a more reliable metric than the peak acceleration for assessing collision behavior in a coarse-grained material. This observation is important to consider when analyzing lander-regolith interactions using the accelerometer data from small-body missions. The objective of future work will be to determine the correct form and applicability of the cited collision models for different impact velocity and gravity regimes.