Shot Velocity Research Articles

Fluid-particle-structure interaction in single shot peening

Shot peening is a widely used cold-working process. Physical phenomena of shot peening are analyzed using the developed fluid-particle-structure coupled solver. The influences of the flow field and shot peening parameters such as the shot impact velocity and shot size are investigated in the case of the falling, impacting, and rebounding single particle. The weakly coupled solver applies the immersed boundary method which enables direct evaluation of the interactions between the unsteady flow field and moving/deforming objects. The elastoplastic object of AISI4340 during the collision of rigid steel shot is analyzed dynamically using the finite element method. Consequently, it is clarified that the flow field of the post-collision between the shot and structure can be characterized by the relative Reynolds number, which is based on the shot diameter and relative velocity between the uniform flow and rebounding shot velocities. As the relative Reynolds number increases, the complex flow field and vortex structures are generated at the collision location. These fluid structures affect the collision phenomena resulting in the random behavior of the shot and the asymmetric indentation in the structure.

Optimization of shot-peening parameters for steel AISI 316L via response surface methodology (RSM): introducing two novel mechanical aspects

The study explores the application of shot-peening (SP) on AISI 316L stainless steel to enhance mechanical properties. It focuses on optimizing SP parameters—coverage percentage (C) ranging from 100 to 4500% and shot velocity (P) between 1.5 and 6 bar while other SP factors were maintained constant—using response surface methodology (RSM) entails creating a mathematical model to analyze data accurately. This model explores interactions among initial configurations to optimize mechanical properties and enhance the performance of the current steel after the SP surface treatment. These properties evaluated include cumulative compressive residual stress (CCRS), cumulative full-width at half-maximum (CFWHM) newfangled factors for researchers to analyze, austenite transformation to martensite, micro-hardness, and surface roughness. Through the RSM model, increasing P leads to an increase in all response values in each one, except for microhardness, which registers a minor decrease from 1.5 to 6 bar. Elevating C promotes responses, excluding roughness, decreasing until 2300% and reaching its minimum. At 4500% C, roughness peaks, exceeding the initial amount at 100% C. In the optimization section, it seeks a passable value for each parameter. Desired responses involve maximizing CCRS, CFWHM, and micro-hardness while minimizing martensite and roughness. For interactions in all responses, at P = 6 bar and C = 1860%, values for each response were CCRS = 218 (MPa.mm), CFWHM = 0.6871 (°.mm), micro-hardness = 394 (HV), martensite conversion = 48 (%), and roughness = 5.45 (µm). Response reassessment in the real tests by comparison RSM model in optimal points showed a minimum error of 4.05 for roughness and a maximum error of 12.09 for CCRS. Other responses contained errors between this spectrum.

Studies on residual stress and surface topography after pneumatic shot peening using discrete element method–finite element method coupled model

After pneumatic shot peening, compressive residual stress is induced on the surface of the target, which will improve the fatigue life. During the process, surface roughness is also induced, which may reduce the fatigue life. To achieve the optimum compressive residual stress with the smallest surface roughness, the formation mechanism of the residual stress field and the surface topography are revealed. Then, pneumatic shot peening is simulated by using a discrete element method–finite element method coupled model. Based on the effects of four variables (the incident angle θ, the initial shot velocity v0, the shot radius R) and the mass flow rate rm on five parameters (the equivalent plastic strain, the equivalent stress, the surface compressive residual stress, the maximum compressive residual stress), the surface roughness is investigated. The results show that it induces a residual elastic–plastic strain after the impact of a single shot, which can form a crater and a hemispherical residual stress field. After the impact of many random shots, scattered craters connect with each other, therewith a rough and continuous surface topography is formed. Scattered residual stress fields couple with each other, and a constant residual stress layer with the compressive residual stress in the surface and the tensile residual stress in the subsurface are formed. All five parameters are determined by the residual elastic–plastic strain, which increases as the augment of the normal impact velocity, the shot mass, and the coverage rate. Along with the increase of θ and rm, these five parameters firstly increase and then decrease; with the increase of v0 and R, these five parameters increase. Therefore, reasonable values of θ, v0, R, and rm should be chosen to obtain the optimum compressive residual stress with as small surface roughness as possible.

Optimization of parameters for the best shot peening effect based on surface response and neural network model

To optimize the peening effect of different shot peening process parameters on metal surfaces, the mapping relationship between different shot peening process parameters and metal surface integrity was obtained. In this paper, ABAQUS software was used to establish a DE-FE (Discrete element-Finite element) random multi-shot analysis model to simulate shot peening, then optimize the shot peening process parameters based on the surface response method(RSM), and finally validate it through experiments and BP(back propagation) neural network model. The result shows that when the shot velocity is 70 m s−1, the impact angle of shot is 61.45°, and the shot diameter is 0.78 mm, the shot peening effect is the best, the surface roughness value is reduced by 101.84%, and the arc height value is increased by 54.66%; the error between the predicted results of BP neural network and the results of numerical analysis is less than 8%. Therefore, the optimized process parameters significantly improve the shot peening effect, but also shows that the BP neural network prediction model can more accurately predict the mapping relationship between the input parameters of shot velocity, shot diameter, and impact angle of shot and the output parameters of roughness value and arc height value.

The relationship between off-ice testing and on-ice performance in male youth Ice hockey players.

Ice hockey demands a unique blend of physical fitness and skill, necessitating a comprehensive understanding of the factors influencing on-ice performance. The present study was designed to examine the relationship between off-ice and on-ice performance measures in male, youth, ice hockey players. Eleven minor hockey players (Age = 9.8 ± 1.1 years) participated in two testing days: (1) off-ice and (2) on-ice assessments. Off-ice assessments included maximal aerobic power, anaerobic fitness, muscular strength (handgrip and single leg squat), muscular endurance (curl-ups and push-ups), muscular power (standing long jump and vertical jump), and 30 m sprinting speed and acceleration. On-ice testing included a 15.2 m maximum speed test, a 6.1 m acceleration test with a continuation into a 47.9 m top speed test, an agility cornering S turn test, and a shot velocity test. Twenty-four out of 33 off-ice variables were significantly correlated with at least one of the 11 on-ice performance variables. From those 24, 10 were included as predictors for at least one of the on-ice performance variables. Each model was composed of either one or two predictors, where the most common predictors were 30 m Run - Split (6.1 m) Sprint time and 30 m Run - Total (30 m) Sprint Max speed (included in four out of 11 models each). The prediction formulas R2 and coefficient of variation ranged from 0.63% to 0.96% and 1.2% to 15.3%, respectively. Diverse off-ice measures of aerobic fitness, anaerobic power, muscular strength, power, and endurance, and sprinting speed, acceleration, and agility are predictive of on-ice performance. The insights gained from this study contribute to the refinement of assessment protocols, fostering a comprehensive approach to optimizing player performance and potential. Understanding the connection between objective off-ice testing and on-ice performance can support tailored training programs and player development in male youth ice hockey.

Effects of peening velocity and coverage on peen forming

As an effective forming technique, peen forming is widely used in sheet metal components with large dimensions. However, the production efficiency is seriously limited as several peening tests are required before actual production. To address this issue, a numerical simulation method of peen forming was proposed. In this work, an elastoplastic peening finite element model was developed to study the relations between process parameters and forming effects. A set of peening forming tests with different coverages and velocities were conducted to validate the model. Results indicate that the maximum errors of converted arc height and forming curvature are less than 5% and 14%, respectively. Additionally, the saturation phenomenon can be observed as the peening coverage reaches 60%. The corresponding depth of the maximum compressive residual stress varies almost linearly with shot velocity. In addition, the best peening forming effect can been achieved a radius of curvature as low as 500 mm, which peening velocity selected 60 m/s.

Assessing the Shooting Velocity According to the Shooting Technique in Elite Youth Rink Hockey Players

This study aimed to report the shooting velocities and to assess the differences in shot velocity according to the techniques used in elite youth male rink hockey players. Fifteen rink hockey players (age = 18.40 ± 1.44 year; body mass = 73.52 ± 6.02 kg; height = 1.76 ± 0.06 m; BMI = 23.61 ± 2.12; sports experience = 6.44 ± 1.76 years) participated in this cross-sectional study. Shooting velocities were assessed for four techniques: slap shot without approach run, drive shot without approach run, slap shot with approach run, and drive shot with approach run. Shooting velocity measurements were conducted using a radar Stalker ATS systemTM. The results demonstrated that drive shots consistently achieved higher velocities compared to slap shots (F(3,56) = 23.9 p < 0.01, ηp2 = 0.58). Additionally, incorporating an approach run significantly increased shooting velocities for both techniques (p < 0.01). These findings hold significant implications for coaches and players seeking to optimize shooting performance in rink hockey.

Effect of Deep Stabilization System Training on the Shot Velocity in Professional Female Handball Players: Cross-sectional Study

The muscles of the deep stabilization system (DSS) affect spinal stabilization, and correct muscular coordination as a prerequisite for a centered position of the joints with optimal biomechanics of movement. Its stimulation by special exercises might lead to better performance in sports. The study verifies the effect of an 8-week intervention to activate DSS on the shot speed in a group of 15 adult elite female handball players. 30 participants were distributed to either the Control group (CG) or the Experimental group (EG). The EG involved special blocks with exercises activating DSS included in regular handball training. The CG involved only casual training. Input and output measurements included shot velocity assessment from various positions with a Stalker Sports Radar Gun. Mann-Whitney U-test was utilized for the statistical analysis with a 0.05 level of significance. The experiment showed a significant speed increase for all three tested throws. Speed increased by 3.82% for a one-handed overhead shot from the ground from a distance of 7m (free throw), 2.23% for a one-handed overhead shot from the ground after a run-up from a distance of 9m, and 2.23% for a one-handed overhead shot from a jump from a distance of 9 m by 2.38%. Specific activation exercises of DSS of the spine led to increased shot speed in handball.

Evaluation of Skin Penetration from Less Lethal Impact Munitions and Their Associated Risk Predictors

<div><b>Introduction:</b> The use of less lethal impact munitions (LLIMs) by law enforcement has increased in frequency, especially following nationwide protests regarding police brutality and racial injustice in the summer of 2020. There are several reports of the projectiles causing severe injuries when they penetrate the skin including pulmonary contusions, bone fractures, liver lacerations, and, in some cases, death. The penetration threshold of skin in different body regions is due to differences in the underlying structure (varying degree of muscle, adipose tissue, and presence or absence of bone).</div> <div><b>Objective:</b> The objective of this study was to further investigate what factors affected the likelihood of skin penetration in various body regions and to develop corresponding penetration risk curves.</div> <div><b>Methods:</b> A total of eight, fresh/never frozen, unembalmed, postmortem human specimens (PMHS) were impacted by two projectile sizes: a 1″ and 5/8″ neoprene rubber ball in various body regions. Impacted body regions included the thigh, abdomen, anterior torso between ribs, anterior torso on a rib, sternum, scapula, posterior torso on a rib, and lower back for a total of a minimum of 24 shots per PMHS. To achieve both a penetrating and non-penetrating shot for each set of impacts, the impact location was assessed post impact to determine if penetration occurred, and the velocity of the next shot was adjusted to target the alternate outcome on the contralateral side within the same body region. Post-test, each PMHS underwent X-rays to determine if any other additional injuries occurred.</div> <div><b>Results:</b> A binary logistic regression analysis was performed to determine which factors (e.g., velocity and energy density) were statistically significant at predicting the risk of penetration. Energy density was utilized as the primary predictor to evaluate the two projectiles’ data together and additional parameters (e.g., skin thickness and BMI) were also tested as co-factors. Statistical significance was obtained with energy density alone for the thigh (<i>p</i> = 0.004), anterior torso between ribs (<i>p</i> = 0.043), lower back (<i>p</i> = 0.04), scapula (<i>p</i> = 0.03), and posterior torso on a rib (<i>p</i> = 0.005). The abdomen region was not significant with energy density alone (<i>p</i> = 0.085) but when BMI was added as a co-factor significance was found to be (<i>p</i> = 0.021). The sternum and anterior torso on a rib were not found to have statistical significance with any of the predictors analyzed. The 50% risk of penetration was found for each region that had statistical significance. The thigh had a 50% risk at 12.62 J/cm<sup>2</sup>, 22.3 J/cm<sup>2</sup> for the anterior torso between ribs, 28.6 J/cm<sup>2</sup> for the lower back, 33.3 J/cm<sup>2</sup> for the scapula, and 34.3 J/cm<sup>2</sup> for the posterior torso on ribs.</div> <div><b>Conclusion:</b> The results support that energy density is a good predictor for estimating the likelihood of the skin to penetrate and that the risk of penetration varies by body region.</div>

DEM-FEM coupling analysis of shot′s energy distribution and target′s residual stress of pneumatic shot peening

Pneumatic shot peening is a widely used surface strengthening method. During the peening process, shots often collide with each other, resulting in large energy loss and small compressive residual stress. In order to achieve the optimum compressive residual stress with as little energy loss as possible, firstly the collision mechanism of shots and the forming and coupling mechanism of the target’s residual stress are revealed, and then pneumatic shot peening is simulated by using DEM-FEM coupling model. Then, the effects of impact angle θ, initial shot velocity v 0, shot diameter d p, and mass flow rate r m on the percentage η of shots with different ratios of the impact velocity to initial shot velocity v m/v 0, the energy loss (EL), the energy transferred from shots to the target (ET), the residual energy (ER) and the compressive residual stress (RS) are investigated. The results show that as many random shots successively impact the target, the RS field induced by each shot couples with some adjacent RS fields induced by other shots, so that disperse RS fields are gradually transformed into a continuous RS layer with the compressive RS in the surface and the tensile RS in the subsurface. With the increase of θ and r m and with the decrease of v 0 and d p, the collision probability of shots increases, so EL also increases and η of shots with a large v m/v 0 decreases. While, ET increases with the increase of v 0 and d p, decreases with the increase of r m, and first increases and then decreases with the increase of θ. ET does not entirely determine but greatly affects the compressive RS field. So, the surface compressive RS and the maximum compressive RS first increase and then decrease with the increase of θ and r m, while the two parameters increase with the increase of v 0 and d p. The optimum parameters of shots are θ = 75°, v 0 = 60 m s−1, d p = 0.25 mm and r m = 2 kg min−1, in which ET reaches 45%, the surface compressive RS of S11 and S33 reach 512 MPa and 510 MPa respectively, and the maximum compressive RS of S11 and S33 reach 665 MPa and 746 MPa respectively.

USZKODZENIA TKANEK PRZEPIÓRKI JAPONSKIEJ (COTURNIX JAPONICA) SPOWODOWANYCH PRZEZ BRON PNEUMATYCZNĄ W BADANIACH OBRAZOWYCH I BALISTYCZNYCH

The widespread availability of legal pneumatic weapons is commonly abused to hurt animals. Determining the shotgun based on animal injuries is complex and requires the knowledge of gunshot wounds and animal tissues. In this study, a detailed gunshot wound analysis was conducted on bird carcasses. An attempt was made to examine damaged soft and hard tissues in Japanese quail. A ballistic device of low energy was used. It was found that the shot of an average velocity of 83 m · s–1 thoroughly penetrates a bird carcass of an average mass of 205.5 g. A head or a neck shot with the same velocity can lead to immediate death. The shot velocity of 110 m · s–1 generates enough energy to move a carcass. These prove how dangerous the weapon is when used to harm small animals. Further studies may contribute to creating a model of bird injuries produced by various shots and result in strict law on possession of low-energy pneumatic weapons in Poland.

Simulation Analysis with Randomly Distributed Multiple Projectiles and Experimental Study of Shot Peening

Shot peening technology is used to improve the fatigue strength of materials and parts, and is one of the most effective surface engineering techniques to prolong fatigue life. In this paper, according to the finite element simulation analysis of shot peening, a randomly distributed multiple-shot finite element model was established. The superimposed effects of multiple projectile impact craters in shot peening are fully considered. The effects of shot velocity, shot peening angle and shot coverage on the residual stress field and surface roughness were studied. The alloy steel 20MnTiB, widely used in the automotive industry, was used as the raw material to process the specimens. The shot peening tests of different process parameters were carried out. The test results verified the correctness and accuracy of the random distribution model of multiple-shot. The shot-peening simulation model proposed in this paper allows a more accurate analysis of the effect of shot-peening parameters on the surface residual stress field and helps to quickly set the correct shot-peening process parameters. This paper further investigates the effect of shot peening parameters on fatigue life, providing a basis for the rational development of shot peening solutions.

Study on the Measurement Method of Shot Velocity and Mechanical Properties Based on Conventional Shot Peening.

Shot velocity is a crucial control parameter that is closely related to the shot peening effect. However, the traditional measurement method of shot velocity corresponding to air pressure is complicated and cannot reflect shot peening parameters (impingement angle, etc.). This study proposes a robust method to measure shot velocity by coupling simulations and experiments. By developing the measurement method presented in this paper, we can quickly and easily derive the linear shot velocity formulas corresponding to a series of impingement angles. The validity is verified and characterized by the arc height, surface roughness, residual stresses, and existing literature. The measured shot velocity can be applied to predict the effect of shot peening by the simulation method in aerospace and automotive industries. In addition, optimization of process parameters in terms of microstructure, microhardness, and mechanical properties is discussed in the context of experiments. This study shows that shot velocity is linearly related to shot peening pressure and is affected by impingement angles. The air pressure and exposure time should not be too large, and no microcracks should be created. The ultimate strength reaches the maximum, and the yield strength is significantly improved.

РАСЧЕТ АПРИОРНЫХ СТАТИЧЕСКИХ ПОПРАВОК В МОВ С УЧЕТОМ ПОЛОЖЕНИЯ ЗАРЯДА ОТНОСИТЕЛЬНО ПОДОШВЫ ЗОНЫ МАЛЫХ СКОРОСТЕЙ

While processing ground-based seismic operations by the reflection method using an explosive excitation source, the standard method of compensation technique for the inhomogeneity of the low velocity layer (LVL) is based on the use of blastholes parameters: shot depth, TSP and velocity of underlying stratum, determined by the apparent velocity of refracted wave. The necessary condition for the applicability of this method is the arrangement of the charge below the base of the LVL. Therefore, to substatiate this method, it is necessary to evaluate the position of the charge relative to the roof of the LWL for each source. If the necessary condition for calculating statics computations is not met, it is necessary to solve the problem of estimating the LVL’s thickness and velocity. The presented work contains the problem of analyzing the position of the charge relative to the LVL’s position and estimating the layer parameters which is solving on the basis of joint analysis of the parameters of wells and wave refracted on the LVL base. The solution of the problem is illustrated by the example of real data processing.

Mapping the geological structures in the Ras El Ush field (Gulf of Suez, Egypt), based on seismic interpretation and 3D modeling techniques

The Ras El Ush field (Gulf of Suez, Egypt) is characterized by various complex structural features, such as evaporite deposits and faulting. Such complex geologic setting results in difficulties in terms of high-resolution seismic interpretation. The seismic energy was masked by the Pre-Miocene salt formation and attenuated by evaporite deposits in the upper Miocene, complicating the seismic interpretation process. Proper geophysical seismic imaging and interpretation of Ras El Ush field's associated structures and sedimentation can provide insights into the geological controls on hydrocarbon systems in the Gulf of Suez rift zone. This study interpreted post-stacked reflection seismic and well data comprising the check shot velocity data to obtain and investigate detailed information about the structural fault orientation and dip of Ras El Ush field. Seismic attributes were employed for improving the fault attributes by eliminating noise and residue of non-faulting events. Additionally, depth maps and 3D structural models were constructed for Rudeis, Nukhul and Matulla formations, the main geological formations within the area of interest. This study presents results from seismic attributes analyses to enhance the detection of the Clysmic fault-offsetting aggregate as well as the minor and major cross faults that passed through the Ras El Ush field. The structural model of the Rudeis, Nukhul, and Matulla formations in the Ras El Ush field exhibits distinct NW-SE to NE-SW fault systems. The models helped in defining geological discontinuities and structural traps, which would help in the development of the field and nearby similar hydrocarbon fields in the Gulf of Suez (Egypt).

Residual stress prediction in shot blasted cobalt–chromium biomedical cast components

ASTM F75 implants distort due to residual stress released after finishing machining operations, causing implants to fail quality requirements. Previous work has shown that a shot blasting cleaning process could be the source of this distortion. Finite element analysis (FEA) is conducted to predict stress and Almen strip arc heights for experimental comparison. 2D and 3D single impact models and 3D multiple impact models are created. 3D multiple impact models with plastically deforming shot are shown to accurately predict the stress state and distortion. For shot with hardness similar to the implants, distortion creating stress magnitudes are induced, with the greatest fluctuations in stress coming from shot velocity. The depth of the predicted compressive stress layer ranges from 0.23 to 0.6 mm.

A CFD-FEM numerical study on shot peening

Surface integrity after shot peening is affected by various parameters. Improper selection of shot peening parameters brings challenges in improving the component's fatigue life or even damages the original surface. An insight into the effects of shot peening parameters on surface integrity is a prerequisite for the appropriate setting of process parameters. This study used the computational fluid dynamics (CFD) method to establish a two-phase flow model describing relationships between shot velocity and pneumatic shot peening machine parameters, such as air pressure and peening distance. A random multi-shots finite element model (FEM) was established to study the effects of shot velocity and shot diameter on surface integrity. Results indicate that the peening distance and air pressure significantly affect shot velocity. Compared to increasing shot velocity, peening with larger diameter shots is more effective in generating compressive residual stress (CRS) and dislocation cell refinement layers. However, it results in a decline in the magnitude of surface compressive residual stress (SCRS). Double shot peening combines the characteristics of different diameter shots, which introduces high SCRS and considerable CRS layer thickness.

A theoretical model for predicting the surface topography of inhomogeneous materials after shot peening

Shot peening is widely used in engineering as a classical strengthening process. Although many studies on shot peening have been done, most have focused on homogeneous target materials. In this paper, a theoretical model is proposed for predicting the surface morphology of inhomogeneous target materials. The topography of target materials after single-shot impact is calculated on the basis of energy conservation and Hertz contact theory, and the final three-dimensional surface topography after multiple-shot impact is obtained through superposition. Single-shot and random multiple-shot finite element models are used to show the advantages of the proposed model over the existing theoretical model for homogeneous target materials. The roughness is found to increase with the shot velocity and shot radius.

Multiple-Shot Impact Model for Vibration-Assisted SMAT Process

Surface mechanical attrition treatment enhances the mechanical properties of metallic materials by inducing high strength layer on the top surface. In this study, multiple-shot impact behavior was modeled for the 7075-T6 aluminum alloy to achieve maximum magnitudes of equivalent stress, plastic strain, residual stress depth, and residual stress. Finite element simulations have been carried out to investigate the effect of selected framework on stress and strains in constituent. The plastic deformation process during SMAT was analyzed using ANSYS/AUTODYN explicit dynamic solver according to shot velocity and diameter with a dynamic explicit finite element method (FEM). Deformation behavior was evaluated after multiple-shot impact.

Mathematical simulation analysis of optimal testing of shot puter's throwing path

Abstract Objective To study the mathematical simulation analysis of shot-putter throwing optimal path. Methods Shot put was simplified as a parabolic motion of a particle, the corresponding mathematical model was established, and the mathematical relationship between the throwing distance and the initial velocity of shot put, the shooting Angle and the shooting height was defined. Results The fitting formula between shooting speed and shooting Angle was obtained by using the fitting method, and the quantitative relationship between them and the ideal shooting Angle was identified. Conclusion The mathematical principle of shot put is revealed through the process of building a model from simple to complex. However, there are still many problems to be solved, among which the height problem is a complex one. At the present level, it is not possible to find a reasonable height, because it involves many factors. However, the development of grey mathematics will provide a beneficial attempt for it to establish a reasonable and scientific model.