Contact Force Distribution Research Articles

Analysis of contact force distribution in a moving granule bed subjected to shear deformation by a set of rollers

Large contact forces on granules could give rise to undesirable attrition. In a new device, referred to as the Particle Shear and Impact tester, granules are subjected to repeated and sequential impact and shearing, the latter effected by two counter-rotating rollers with differential angular speeds and an adjustable gap between the rollers. This enables the contact force distribution to be varied in order to apply representative contact forces, as experienced in manufacturing plants. Granule flow in the rollers is simulated by Distinct Element Method for several roller gap sizes. The resulting contact force distribution is compared to that from shear cell simulations for representative plant normal stresses (8 to 15 kPa), in order to calibrate the appropriate gap size. The 90th percentile of the contact forces distributions from the two simulations are matched to set the gap size. A roller gap size approximately 3.5 times the 90th percentile of the particle size (based on number distribution) gives a good match of the interparticle contact forces between the rollers and the shear cell. This enables replicating the stresses that granules experience in plants, whether during handling and transport, or during more severe stressing conditions, e.g. compaction or even grinding, thereby assessing attrition or fragmentation propensity of granules.

Procedure of the updated calculations of disks of aero – engines with removable blades a finite element method in three – dimensional statement in the environment of Femap/Nastran

Problematic. At adaptation of a design of discs of rotor of air gas-turbine drives (GTD) it is necessary to conduct, in particular, strength calculations for what to create the computer models corresponding to stated designs (delineations) and operation conditions. If creation of a geometrical part of model does not call special difficulties the algorithm of creation of an is finite-element grid models for carrying out of calculations of performances of the disc stress-strain conditions (SSC) with blades can be modified taking into account development of programs for calculate.
 Research objective. To offer the algorithms allowing with the set exactitude to calculate performance of the SSC of discs with blades on personal computers, and also to represent outcomes in the form of schedules of type "surface".
 Realization technique. On an example of the disc of 2nd stage of the compressor of GTD the algorithm of construction of a three-dimensional is finite-element grid of the disc of GTD from the separate blocks which have been "pasted together" in a unified grid has been created. Numerical calculations (a contact problem of thermoelasticity, isotropic materials) are carried out. For preparation of construction of schedules of type "surface" the interface program of transformation of the table of columns in the two-dimensional table is created.
 The results of research. Are created and explicitly techniques of reaching of research objectives are described.
 Conclusions. The created techniques allow to carry out on the limited computer powers exact enough control calculations of discs with blades in three-dimensional statement, to conduct visualisation of distribution of stresses and contact forces of a zone of a contact "disc-blades" in the form of schedules of type "surface".

Computerized occlusal analysis of two different removable retainers used during retention phase- A Randomized controlled trial

ABSTRACT Aim: To evaluate and compare occlusal contact force distribution, occlusion time and disclusion time following wear of Begg’s wrap around retainer and Vacuum formed retainer after completion of orthodontic treatment using a T-scan III. Materials and Methods: Twenty subjects after completion of active orthodontic treatment were randomly allocated into two groups, Group I – Begg’s wrap-around retainer (n-10) and Group II–vacuum formed retainer (n-10) one patient was lost to follow up in each group and the final sample size assessed at T1 in each group was 9. T-scan III was used at two-time intervals, T0 – first scan taken immediately after debonding and T1 – taken during retention any time between 10 and 12 months. Comparison of parameters within the groups was done using paired t-test and comparison between the groups was done using independent t-test. Results: No statistically significant difference in the distribution of occlusal contact forces was noted in both groups at T0 and T1 (p value<0.05). Disclusion time reduced in both groups at T1 but a statistically significant reduction in the disclusion time of left lateral excursive movement and protrusive movements (p value<0.05) was noted (T0-T1) in Group I. Statistically significant increase in the occlusion time was noted in Group II (T0-T1) at T1 between the two groups. Conclusion: No differences in occlusal contact force distribution was noted within and between the two groups. Disclusion time reduced in subjects on Begg’s wrap around retainers indicating favourable muscle activity and Occlusion time increased in subjects on vacuum formed retainers.

Comparative 3D DEM simulations of sand\u2013structure interfaces with similarly shaped clumps versus spheres with contact moments

Three-dimensional simulations of a monotonic quasi-static interface behaviour between initially dense cohesionless sand and a rigid wall of different roughness during tests in a parallelly guided direct shear test under constant normal stress are presented. Numerical modelling was carried out by the discrete element method (DEM) using clumps in the form of convex non-symmetric irregularly shaped grains. The clumps had an aspect ratio of 1.5. A regular grid of triangular grooves (asperities) along the wall with a different height at the same distance was assumed. The numerical results with clumps were directly compared under the same conditions with our earlier DEM simulations using pure spheres with contact moments with respect to the peak and residual interface friction angle, width of the interface shear zone, ratio between grain slips and grain rotations, distribution of contact forces and stresses. The difference between the behaviour of clumps and pure spheres with contact moments proved to be noticeable in the post-peak regime due to a different particle shape. The rolling resistance model with pure spheres was proved to be limited for capturing particle shape effects. Three different boundary conditions along the interface were proposed for micropolar continua, considering grain rotations and grain slips, wall grain moments and wall grain forces, and normalized interface roughness. The numerical results in this paper offer a better understanding of the interface behaviour of granular bodies in DEM and FEM simulations.

Micromechanical description of the compaction of soft pentagon assemblies.

We analyze the isotropic compaction of assemblies composed of soft pentagons interacting through classical Coulomb friction via numerical simulations. The effect of the initial particle shape is discussed by comparing packings of pentagons with packings of soft circular particles. We characterize the evolution of the packing fraction, the elastic modulus, and the microstructure (particle rearrangement, connectivity, contact force, and particle stress distributions) as a function of the applied stresses. Both systems behave similarly: the packing fraction increases and tends asymptotically to a maximum value ϕ_{max}, where the bulk modulus diverges. At the microscopic scale we show that particle rearrangements occur even beyond the jammed state, the mean coordination increases as a square root of the packing fraction, and the force and stress distributions become more homogeneous as the packing fraction increases. Soft pentagons experience larger particle rearrangements than circular particles, and such behavior decreases proportionally to the friction. Interestingly, the friction between particles also contributes to a better homogenization of the contact force network in both systems. From the expression of the granular stress tensor we develop a model that describes the compaction behavior as a function of the applied pressure, the Young modulus, and the initial shape of the particles. This model, settled on the joint evolution of the particle connectivity and the contact stress, provides outstanding predictions from the jamming point up to very high densities.

Analysis of Radial Roller Bearing Rating Life in Complex Loading Conditions

Abstract An approach for accurate life analysis of radial roller bearings in complex loading conditions is presented. It employs ISO 16281 and accounts not only for external radial loads applied to the inner ring but also for (i) internal bearing clearance, (ii) flexibility of the bearing rings, (iii) rings out-of-roundness, (iv) inertia effects, (v) rolling elements profile, and (vi) rings misalignment. In the last decades, these factors have been becoming more and more important for modern high-performance jet engines, whose shafts are commonly hollow and the housing and the rings thicknesses may be of comparable magnitudes. To obtain the distribution of internal contact forces, an advanced static model of a bearing with deformable, potentially misaligned, rings is developed. The bending deformations of the rings are reproduced superimposing deformed shapes from each of the arising internal contact force applied individually. Bearing rollers are allowed to have non-cylindrical profile, and its geometry is approximated by means of slices each having constant diameter. A robust numerical scheme for solving the resultant set of equations with the aid of the barrier functions method is constructed. To increase even further the accuracy of rating life analysis, distributions of the contact stresses between the roller and the ring surfaces, obtained by solving numerically the problem of non-Hertzian interaction, are added to computations. A numerical benchmark test is presented to demonstrate the applicability of the developed approach. It shows how the aforementioned factors influence the bearing contact forces and its rating life.

Effects of fixed wall and pebble size ratio on packing properties and contact force distribution in binary-sized pebble mixed beds at the maximum packing efficiency state

The binary-sized pebble mixed beds at the maximum packing efficiency state were numerical simulated by the DEM simulation to investigate the effect of fixed wall and pebble size ratios. The evolution of the distribution of packing fraction and porosity, radial distribution function and contact force were given and analyzed with emphasis on the effects of the fixed wall and pebble size ratio. The results showed that the fixed wall will result in a reduction of average packing fraction and an obvious wall effect in local porosity distribution. With the increase of the pebble size ratio, the volume fraction of the wall affected regions gradually decrease. The variation of the local packing fraction of the binary-sized pebble bed is mainly determined by the partial packing fraction of large pebbles and the partial packing fraction of small pebbles, respectively, in the regions close to the fixed wall. Furthermore, the fixed wall has little effect on the radial distribution function and contact force. However, the pebble size ratios have great influence on the radial distribution function and the contact force in binary-sized pebble bed at the maximum packing efficiency state. With the increase of the pebble size ratio, the radial distribution functions of the whole pebble beds are consistent with that of small pebbles, and approach to that of the mono-sized pebble bed. In addition, with the increase of the pebble size ratio, a higher contact force can be obtained in pebble beds.

The Effects of 180 years of Aging on the Physical and Seismic Properties of Partially Saturated Sands

AbstractConstraining how the physical properties and seismic responses of recently deposited sands change with time is important for understanding earthquake site response, subsurface fluid flow, and early stages of lithification. Currently, however, there is no detailed (cm‐scale) assessment of how sand's physical properties and associated seismic velocities evolve over the first two centuries after deposition. Here, we integrate sedimentation rates with seismic velocity and sediment physical properties data to assess how the vadose zone sands at Port Royal Beach, Jamaica, change within 180 years after deposition. We show that compressional and shear wave velocities increase with sediment age, whereas porosity, grain size, sorting, mineralogy, and cementation fraction remain relatively unchanged during the same period. Rock physics models (constrained by the measured physical properties) predict constant seismic velocities at all sites regardless of sediment age, though misfits between modeled and observed velocities increase with sediment age. We explain these misfits by proposing that shallow sands undergo microstructural grain reorganization that leads to a more uniform distribution of grain contact forces with time. Our results imply that beach sands undergo a previously undocumented lithification process that occurs before compaction.

DEM exploration of confining stress effect in cyclic liquefaction of granular soils

Confining stress is a major consideration in the assessment of liquefaction resistance of granular soils. In this study, the influence of confining stress to cyclic liquefaction from micromechanical perspectives are explored using DEM simulations. Eight samples with different confining stresses and void ratios are prepared and subjected to undrained cyclic loading tests to reach initial liquefaction. It is observed that the influence of confining stress to coordination number of the sample before shearing is limited. However, confining stress has a significant influence to probability distribution of normal contact forces. Sample with higher confining stress has higher fraction of medium normal forces. During liquefaction process, evolution of coordination number versus effective vertical stress for all samples converge to a unique curve, which may depict the minimum value of coordination number for the load-bearing structure to sustain the effective stress. Different anisotropic sources undertake different roles in shear resistance. The contribution of tangential contact force anisotropy to shear resistance is gradually replaced by contact normal anisotropy.

Jamming and force distribution in growing epithelial tissue

We investigate morphologies of proliferating cellular tissues using a newly developed numerical simulation model for mechanical cell division and migration in 2D. The model is applied to a bimodal mixture consisting of stiff cells with a low growth potential and soft cells with a high growth potential; cancer cells are typically considered to be softer than healthy cells. In an even mixture, the soft cells develop into a tissue matrix and the stiff cells into a dendrite-like network structure. When soft cells are placed inside a tissue consisting of stiff cells (to model cancer growth), the soft cells develop to a fast growing tumor-like structure that gradually evacuates the stiff cell matrix. The model also demonstrates 1) how soft cells orient themselves in the direction of the largest effective stiffness as predicted by the theory of Bischofs and Schwarz (Proc. Natl. Acad. Sci U.S.A., 100, 9274--9279 (2003) and 2) that the orientation and force generation continue a few cell rows behind the soft-stiff interface. With increasing inter-cell friction, tumor growth slows down and cell death occurs. The contact force distribution between cells is demonstrated to be highly sensitive to cell type mixtures and cell-cell interactions, which indicates that local mechanical forces can be useful as a regulator of tissue formation. The results shed new light on established experimental data.

A simplified formulation for predicting wrinkling of thin-wall elbow tube in granular media–based push-bending process

Wrinkling is the key forming defect in thin-wall tube bending process, when the wall thickness-to-diameter ratio is smaller than 0.01. The granular media-based thin-wall elbow push-bending process involves filling a tube with spherical particles and pushing the tube into a die to bend a tubular blank into an elbow shape. If the wall thickness of tube is smaller than the particle size, wrinkling significantly depends on micro contact force distribution in granular media, and the granular media cannot be approximately simulated by FEM. In the present paper, an elbow tube with 0.3 mm wall thickness, 30 mm outer diameter, and 90 mm bending radius is formed by granular media-based push-bending process. The wrinkling is investigated; especially, the micro contact force distribution at the initial buckling location is observed based on a 3D FEM-DEM coupling model. In the coupling model, FEM is used to simulate bending deformation of tubular blank, and DEM is used to simulate micro contact forces of particle flow. Finally, a simplified formulation is proposed for predicting wrinkling of thin-wall elbow tube in granular media-based push-bending process and validated by experiment of an elbow tube with 0.7 mm wall thickness, 70 mm outer diameter, and 105 mm bending radius.

Development of flexible tactile sensor for the envelop of curved robotic hand finger in grasping force sensing

Intelligent robotic hand with integrated tactile sensor is able to perform real-time tactile information sensing, which is crucial for dexterous grasping and manipulation. This paper presents a novel flexible tactile sensor with 18 sensing units to envelop a complex-shaped robotic hand finger for grasping force measurement. A new approach based on point cloud fitting and triangular searching is developed to determine the special configuration of these 18 sensing units on the complex finger surface, and it is used for the structural design of the flexible tactile sensor. The fabrication process to make the tactile sensor is developed and fabricated tactile sensor features high flexibility and can be perfectly enveloped around robotic hand finger. Calibration results show that the sensor has relatively high sensitivities for three-axis force sensing: 1.87 V/N at 0.1 ~ 0.7 N and 0.47 V/N at 0.7 ~ 3 N for z-axis normal force sensing, 1.59 V/N and 1.49 V/N at −1 ~ 1 N for x- and y-axes shear force sensing, respectively. Besides, the tactile sensor has good reproducibility and generally low cross-talk interferences between the sensing units. After being wrapped onto robotic hand finger, this sensor is utilized to measure the distributed contact forces when the robotic hand grasps different objects. The effects of grasping movements on the generated contact forces are analyzed. The obtained results demonstrate that the developed tactile sensor has great potentials for the perception of tactile information in human-robotic interactions.

Automatic ultrasound scanning robotic system with optical waveguide-based force measurement.

The three-dimensional (3D) ultrasound (US) imaging realized by continuous scanning of a region is of great value for medical diagnosis and robot-assisted needle insertion. During scanning, the contact force and posture between the probe and skin of the patient are crucial factors that determine the quality of US imaging. We propose a robotic system for automatic scanning of curved surfaces with a stable contact force and vertical contact posture (the probe is parallel to the normal of the surface at the contact point). A 6-DOF robotic arm is used to hold and drive a two-dimensional (2D) US probe to complete automatic scanning. Further, a path-planning strategy is proposed to generate the scan path covering the selected area automatically. We also developed a novel force-measuring device based on optical waveguides to measure the distributed contact force and contact posture. Based on the measured force and posture, the robotic arm automatically adjusts the position and orientation of the probe and maintains a stable contact force and vertical contact posture at each scan point. The novel force-measuring device is easy to fabricate, integrates with the probe and has the capacity of measuring the force distributed on the contact surface and estimating the contact posture. The experimental results of automatic scanning of a US phantom and parts of the human body demonstrate that the proposed system performs well in automatically scanning curved surfaces, maintaining a stable contact force and vertical contact posture and producing a good quality 3D US volume. An automatic US scanning robotic system with an optical waveguide-based force-measuring device was developed and tested successfully. Experimental results demonstrated the feasibility of the proposed system to scan the human body.

Behaviour of an angular contact ball bearing with three-dimensional cubic-like defect: A comprehensive non-linear dynamic model for predicting vibration response

The dynamic model of an asymmetric defects on an angular contact ball bearing raceway has not been fully described before. An advanced 10-degree-of-freedom dynamic model that includes detailed contact forms between a three-dimensional cubic-like defect and balls is proposed in this article. Examples are load distributions, ball passing defect profiles, varying effective stiffness between balls and raceways, and the impulse response caused by the collision of balls and defect edges. The results suggest that the circumferential size of the 3-D defect has a significant effect on the contact force distribution, which consequently generates impulse vibration in the bearing system. The analysis on the axial and circumferential sizes of defect show that the extension of the defect in the circumferential direction should be avoided. Additionally, the reduction of the radial-axial load ratio could mitigate the vibration impulses.

On the Effect of Grain Fragmentation on Frictional Instabilities in Faults With Granular Gouge

AbstractThe evolution of frictional strength during stick‐slip dynamics of a fault system is key to understanding earthquake nucleation and rupture patterns. In mature faults, granular gouge is produced by wear, comminution or fragmentation during tectonic movements. In this work, we introduce a fragmentation model in the simulation of a sheared granular fault to explore the influence of grain breakage on the stick‐slip dynamics. With fragmentation of highly stressed particles, the fault frictional strength increases accompanied by many small slip events triggered by particle breakage. The small fragments produced by particle breakage are not only stronger and more difficult to break, but they also change the distribution of contact forces, leading to the strengthening of the fault system. Based on statistical analyses on the size distribution of slip events with different particle strengths, we find that with lower particle strength, slip events become more correlated with particle fragmentation events and that the number of large slip events decreases. In addition, our analyses on the relationship between slip and particle fragmentation events reveal three types of correlations: In the first and second types, particle fragmentation events trigger micro or major slips, respectively. In the third category, large‐scale particle fragmentations take place at the end of large slip events owing to stress localization during post‐slip particle rearrangements. Our results in this work highlight the role of micromechanics of particle fragmentation in the failure of fault damage zones and help in understanding the relation between particle breakage and frictional failures.

Knee loading in OA subjects is correlated to flexion and adduction moments and to contact point locations

This study evaluated the association of contact point locations with the knee medial and lateral contact force (Fmed, Flat) alterations in OA and healthy subjects. A musculoskeletal model of the lower limb with subject-specific tibiofemoral contact point trajectories was used to estimate the Fmed and Flat in ten healthy and twelve OA subjects during treadmill gait. Regression analyses were performed to evaluate the correlation of the contact point locations, knee adduction moment (KAM), knee flexion moment (KFM), frontal plane alignment, and gait speed with the Fmed and Flat. Medial contact point locations in the medial–lateral direction showed a poor correlation with the Fmed in OA (R2 = 0.13, p = 0.01) and healthy (R2 = 0.24, p = 0.001) subjects. Anterior–posterior location of the contact points also showed a poor correlation with the Fmed of OA subjects (R2 = 0.32, p < 0.001). Across all subjects, KAM and KFM remained the best predictors of the Fmed and Flat, respectively (R2 between 0.62 and 0.69). Results suggest different mechanisms of contact force distribution in OA joints. The variations in the location of the contact points participate partially to explains the Fmed variations in OA subjects together with the KFM and KAM.

Dataset of Tactile Signatures of the Human Right Hand in Twenty-One Activities of Daily Living Using a High Spatial Resolution Pressure Sensor.

Successful grasping with multi-fingered prosthetic or robotic hands remains a challenge to be solved for the effective use of these hands in unstructured environments. To this end, currently available tactile sensors need to improve their sensitivity, robustness, and spatial resolution, but a better knowledge of the distribution of contact forces in the human hand in grasping tasks is also necessary. The human tactile signatures can inform models for an efficient control of the artificial hands. In this study we present and analyze a dataset of tactile signatures of the human hand in twenty-one representative activities of daily living, obtained using a commercial high spatial resolution pressure sensor. The experiments were repeated for twenty-two subjects. The whole dataset includes more than one hundred million pressure data. The effect of the task and the subject on the grip force and the contribution to this grip force made by the different hand regions were analyzed. We also propose a method to effectively synchronize the measurements from different subjects and a method to represent the tactile signature of each task, highlighting the hand regions mainly involved in the task. The correlations between hand regions and between different tasks were also analyzed.

Medial Unicompartmental Knee Arthroplasty with a Mobile-Bearing Implant.

For patients with isolated medial knee arthritis, unicompartmental knee arthroplasty (UKA) is an appealing surgical option. Compared with total knee arthroplasty (TKA), UKA is less invasive, preserves more native bone stock, has lower perioperative morbidity and mortality1,2, allows for quicker recovery1,2, and has higher patient satisfaction2,3. It also allows for more dynamic proprioception and postural control, allowing for function more similar to a native knee4. Proper surgical technique and patient selection are critical to the growing success of UKA. The general principles of UKA are to remove and replace the diseased femoral and tibial joint surfaces while restoring limb alignment. The key steps of this procedure are demonstrated in the video article: (1) patient evaluation, (2) patient positioning, (3) surgical exposure, (4) tibial guide placement and resection, (5) femoral guide placement and resection, (6) knee balancing and implant trialing, (7) preventing impingement, (8) final tibial preparation, (9) final component placement, and (10) closure and postoperative course. Patients should first exhaust all nonoperative treatments before considering UKA. For those patients who do not meet the appropriate indications for UKA, TKA is the most acceptable alternative treatment. In active patients <55 years old without bone-on-bone osteoarthritis, a high tibial osteotomy may be considered. When considering UKA, options include both mobile-bearing and fixed-bearing designs. The potential advantages of UKA over TKA make it an attractive option for the appropriate patient. Recently, indications for UKA have expanded to include (1) isolated noninflammatory bone-on-bone arthritis in the medial compartment; (2) retained full-thickness cartilage in the lateral compartment, best visualized on valgus-stress radiographs; (3) a functionally normal medial collateral ligament; and (4) a functionally normal anterior cruciate ligament5. Mobile-bearing UKA designs consist of a dual articulation between the concave polyethylene insert and the metallic tibial and spherical femoral components, which allows for distribution of contact forces over a large surface area6. In contrast, fixed-bearing designs have a flat polyethylene insert that does not conform to the femur. Current data do not demonstrate a clear difference in clinical performance between the 2 bearings. However, a recent systematic review has shown lower polyethylene wear rates in mobile-bearing implants7. The survivorship of mobile-bearing UKA ranges from 85% to 98% at 10 years8-12 and from 79% to 94% at 15 years8,13,14. The most common indications for revision include aseptic loosening (36%), progression of osteoarthritis (20%), and unexplained pain (11%)7. Bearing dislocation is a unique complication for mobile-bearing UKAs, with reported rates between 0.3% to 4.2%6,10,12. Always inspect all compartments of the knee for evidence of substantial degenerative changes prior to proceeding with UKA. If there is advanced arthritis in other compartments, the decision should be made to proceed with TKA instead. Therefore, preoperatively, all patients indicated for UKA should also sign a consent form for TKA, and TKA implants should be available in case they are needed.When assessing bearing size, it is important that there is no axial loading through the heel to properly assess the flexion gap. Intraoperatively, this can be done by elevating the thigh so that the foot hangs freely. The trial spoon should fit into the joint without substantial resistance or effort.Spigots do not reference the end of the bone. Rather, they reference the end of the spigot hole that was drilled using the initial 0 spigot.Spigot number represents the total thickness of additional bone that will be removed from the first mill cut.Confirm the amount of bone that was resected by inspecting the small rim of bone that remains around the spigot hole after milling.

Inertial Force Transmission in Dense Granular Flows.

Dense granular flows are well described by several continuum models; however, their internal dynamics remain elusive. This study explores the contact force distributions in simulated steady and homogenous shear flows. The results demonstrate the existence of high magnitude contact forces in faster flows with stiffer grains. A proposed physical mechanism explains this rate-dependent force transmission. This analysis establishes a relation between contact forces and grain velocities, providing an entry point to unify a range of continuum models derived from either contact forces or grain velocity.

Vision-Based Tactile Sensor Mechanism for the Estimation of Contact Position and Force Distribution Using Deep Learning.

This work describes the development of a vision-based tactile sensor system that utilizes the image-based information of the tactile sensor in conjunction with input loads at various motions to train the neural network for the estimation of tactile contact position, area, and force distribution. The current study also addresses pragmatic aspects, such as choice of the thickness and materials for the tactile fingertips and surface tendency, etc. The overall vision-based tactile sensor equipment interacts with an actuating motion controller, force gauge, and control PC (personal computer) with a LabVIEW software on it. The image acquisition was carried out using a compact stereo camera setup mounted inside the elastic body to observe and measure the amount of deformation by the motion and input load. The vision-based tactile sensor test bench was employed to collect the output contact position, angle, and force distribution caused by various randomly considered input loads for motion in X, Y, Z directions and rotational motion. The retrieved image information, contact position, area, and force distribution from different input loads with specified 3D position and angle are utilized for deep learning. A convolutional neural network VGG-16 classification modelhas been modified to a regression network model and transfer learning was applied to suit the regression task of estimating contact position and force distribution. Several experiments were carried out using thick and thin sized tactile sensors with various shapes, such as circle, square, hexagon, for better validation of the predicted contact position, contact area, and force distribution.