Contact Pressure Distribution Research Articles

Determining the characteristics of contact interaction between structural elements with varied properties of surface layers

The object of this study is the stressed-strained state of contacting elements of close-shaped machine-building structures. The presence and flexibility of surface layers and coatings are modeled. There are cases of the matching shape of the contacting surfaces of bodies, as well as the perturbation of the shape of these surfaces. The task being solved relates to the fact that the analysis methods of such bodies contact interaction are not yet sufficiently developed. It was established that for the case of the matching shape of contacting surfaces, the contact area does not depend on the level of loads. In this case, the contact pressure distribution is proportional to the operating load. Such features of the solution do not depend on the properties of the materials of surface layers. A different case is when the shape of the contacting surfaces of bodies is disturbed. In particular, it was established that the properties of the materials of surface layers exert a strong influence on the shape and dimensions of bodies contact area, as well as on the distribution of contact pressure (the difference is 1.5–2.5 times or more). The theory of variational inequalities is used to model the stressed-strained state of contacting bodies. As a result, the problem about contact interaction of bodies with surfaces of close shape is reduced to the problem of minimizing the modified energy functionality. The minimization is carried out on a set of distributions of displacements, which describes conditions of bodies not penetrating each other. The finite element method is used to discretize the problem of determining the stressed-strained state of contacting bodies. The parametric model built makes it possible to determine the stressed-strained state of contacting bodies when the disturbance of the nominal shape of the bodies and the properties of their surface layers is varied

ANALYSIS OF THE STRESS-STRAIN STATE OF CONTACTING ELEMENTS OF HYDRAULIC TRANSMISSIONS FOR ADVANCED TANK TRANSMISSIONS UNDER VARIATION AND PERTURBATION OF THE SHAPE OF SURFACES AND PROPERTIES OF BODY MATERIALS

The paper describes the study of the stress-strain state and of the contact interaction of hydraulic transmission elements for advanced tank transmissions. The shape of the treadmill and the ball piston of the radial hydraulic volume transmission, as well as the stiffness of the surface layers of these elements, are varied. A change in the shape and size of the contact area between the piston and the raceway of the hydrovolumetric transmission is observed. At the same time, the distribution of contact pressure, its nature, and maximum values change. It has been established that in certain design variants, the oval shape of the contact area is transformed into a rounded rectangle, a dumbbell-shaped figure, or two isolated areas. This, in turn, has a significant impact on the stress-strain state of the ball piston and stator ring of the fluidized bed transmission. By varying these parameters, the dependence of strength characteristics on them was established. Such regularities are the basis for substantiating advanced technical solutions for hydraulic volumetric gears in terms of strength, durability, and load capacity. The developed parametric model has the property of being extended to various other parameters. This makes it possible to create specialized databases. These databases concentrate information on the dependence of the strength characteristics of hydraulic-volume gears on certain parameters. Accordingly, it is possible to solve the inverse problem of substantiating rational technical solutions for hydraulic gears. The developed approach can be extended to a wide class of structural elements.

Modeling of sliding contact of a system of asperities and coated viscoelastic half-space

Problem of sliding of a periodic system of asperities along the boundary of a viscoelastic half-space with a coating is under consideration. The coating is modeled by a layer with flexural rigidity. The solution is based on reducing the problem to the contact of a limited system of asperities with the action of others being replaced by distributed pressure; the accuracy of such approach is evaluated. The numerical-analytical solution is based on double integral Fourier transforms, the boundary element method and the iterative procedure. The influence of the shape of asperities, sliding velocity, and coating thickness on the deformation component of the friction force and on the effect of mutual influence of asperities was analyzed. To identify the effect of mutual influence, a comparison was made of the results (distribution of contact pressure and friction force) obtained for multiple contacts and for the isolated asperity. For comparison, the results of solving a similar problem for viscoelastic half-space without a coating were obtained and analyzed.

Sealing Performance Analysis of Lip Seal Ring for High-Speed Micro Bearing

This article focuses on the problem of sealing failure in high-speed micro bearings. Based on a thermal-stress coupled finite element model, the distribution of equivalent stress and contact pressure of the sealing ring and the influence of various factors on the sealing performance are analyzed. Based on this, the Latin Hypercube sampling method, Kriging surrogate model and genetic algorithm are used to find the optimal combination of sealing performance. Finally, the accuracy of the model and method is verified through orthogonal experiments. Research has found that the maximum equivalent stress of the seal ring is 0.59234 MPa, and it increases first and then decreases with the increase in lip inclination angle, friction coefficient and radial interference amount, increases with the increase in lubricant temperature, and decreases with the increase in bearing rotation speed. The maximum contact pressure is 0.20433 MPa, and it decreases with the increase in the lip inclination angle, increases first and then decreases with the increase in the friction coefficient, and decreases first and then increases with the increase in the lubricant temperature, bearing rotation speed and radial interference amount. The most significant factor affecting the equivalent stress of the seal ring is the lubricant temperature, and the most significant factor affecting the contact stress is the interference fit amount. When the seal lip inclination angle is 43.99°, the friction coefficient is 0.01 mm, the lubricant temperature is 111.5 °C, the bearing rotation speed is 28,853 rpm and the radial interference amount is 0.04 mm, the sealing performance of the sealing ring is optimal.

Monitoring and Analysis of Circumferential Pressure for Long‐Distance Pipe Jacking Construction in Composite Strata

ABSTRACTAt present, the monitoring methods of mechanical parameters of pipe in the process of pipe jacking construction generally have the disadvantages of low data reliability and poor timeliness. Especially in the jacking construction in complex strata, if the jacking parameters and lubrication grouting parameters cannot be adjusted in real time according to the circumferential pressure, it is easy to cause pipe sticking accident. Based on the Inner Mongolia Water Diversion Project from ChaorHe to Liaoning, this paper adopts the LPWA low‐power wide‐area network wireless sensing system based on 5G and IOT technology to realize the real‐time wireless monitoring of the contact pressure and lubrication grouting pressure of the underground pipe jacking pipe. Through the parameters obtained by the wireless sensing system, the stress characteristics of a specific pipe traversing different strata and under different working conditions were studied, and the change rule of circumferential contact pressure of the pipe and the influence of various factors on it were analyzed. The results show that: by analyzing the circumferential contact pressure obtained by the wireless sensing system, the pressure distribution of the pipe in the top soft and bottom hard strata is right>left>bottom>top; in the full‐section strata, the destruction of the lubricating mud sleeve will lead to the same contact pressure on one side and the bottom of the pipe; when the pipe traverse the interfaces of different rock strata, the stability of the lubricating mud sleeve will be affected, and thus the circumferential contact pressure will be altered. The above results are consistent with the theoretical prediction and can provide reference for the actual project. In conclusion, the wireless sensing system can accurately reflect the distribution of circumferential contact pressure of the pipe under different strata, and provide reliable data support for improving construction efficiency and safety.

Interplay Between Wear and Thermal Expansion in 6082 Aluminum: A Simulation and Experimental Study

This study investigates how wear and thermal expansion interact in 6082 aluminum, utilizing a pin-on-disc tribometer and finite element analysis under diverse mechanical conditions. The findings show that thermal expansion reduces contact area by forming a protrusion at the contact interface. This interaction between wear and thermal expansion causes dynamic shifts in the contact region and pressure distribution, affecting the disc center and altering wear progression and temperature patterns. High thermal expansion shifts maximum wear from the contact center to outer regions, especially at higher speeds and loads. Without thermal expansion, wear-only conditions overestimate friction dissipation, resulting in a higher peak temperature. These results highlight the critical role of thermal expansion in shaping wear patterns and contact behavior in sliding applications. This research offers insights for optimizing tribological performance in 6082 aluminum, with potential applications in other materials.

Biomechanical testing of virtual meniscus implants made from a bi-phasic silk fibroin-based hydrogel and polyurethane via finite element analysis

ObjectiveTo investigate the suitability of different material compositions and structural designs for 3D-printed meniscus implants using finite element analysis (FEA) to improve joint function after meniscal injury and guide future implant development. DesignThis experimental study involved in-silico testing of a meniscus model developed from two materials: a specially formulated hydrogel composed of silk fibroin (SF), gelatine, and decellularized meniscus-derived extracellular matrix (MD-dECM), and polyurethane (PU) with stiffness levels of 54 and 205 MPa. Both single-material implants and a two-volumetric meniscus model with an SF/gelatine/MD-dECM core and a PU shell were analysed using FEA to simulate the biomechanical performance under physiological conditions. ResultsThe hydrogel alone was found to be unsuitable for long-term use due to instability in material properties beyond two weeks. PU 54 closely replicated the biomechanical properties of an intact meniscus, particularly in terms of contact pressure and stress distribution. However, hybrid implants combining PU 54 with hydrogel showed potential but required further optimization to reduce stress peaks. In contrast, implants with a PU 205 shell generated higher induced stresses, increasing the risk of material failure. ConclusionsFEA proves to be a valuable tool in the design and optimization of meniscal implants. The findings suggest that softer PU 54 is a promising material for mimicking natural meniscus properties, while stiffer materials may require design modifications to mitigate stress concentrations. These insights are crucial for refining implant designs and selecting appropriate material combinations before physical prototype production, potentially reducing costs, time, and the risk of implant failure.

Frictional Abrasion of Rubber: Transition from Sliding to Rolling

ABSTRACT To develop applicable friction and wear models on tire scale, reliable test data are required. Consequently, friction tests on block level are requested because the distribution of contact pressure as well as slip velocity is nearly homogeneous at the contact surface of the sliding rubber block. However, wear mechanism and energy intensity levels of sliding rubber blocks and rolling rubber wheels or tires differ significantly. Consequently, linking both sliding and rolling frictional abrasion is required; thus, a wear model for rubber material is introduced to consider both deformation slip and sliding. The model input for sliding friction and resulting wear rate is derived from linear friction test experiments using sliding rubber blocks at different loading. A unique and sophisticated re-mesh algorithm ensures proper mesh modification due to abrasion of the structure. A wear energy evolution approach is developed to consider low abrasion with small sliding distances to predict wear at rolling rubber wheels. The simulation framework of abrasion modeling is successfully validated using laboratory abrasion tests.

An analytical approach to incomplete spherical conformal contact: application on self-lubricating spherical plain bearings

PurposeContact pressure is a critical factor that significantly influences the wear of self-lubricating spherical plain bearings. The purpose of this paper is to address the issue of conformal contact in spherical plain bearings with a self-lubricating fabric liner, and then a universal theoretical analytical model for conformal contact between frictionless spheres is proposed.Design/methodology/approachThis study establishes an analytical model to calculate the conformal contact in spherical plain bearings and verifies the new model by finite element analysis.FindingsThe new model proposed in this paper overcomes the limitations of elastic half-space and small-deformation assumptions. After conducting accuracy validation, it was observed that the computational error of the new model has significantly decreased in comparison to the Johnson model. For a conformal contact with a clearance of 0, the error is nearly 0.Practical implicationsThe analytical model can calculate the contact pressure distribution of self-lubricating spherical plain bearings bonded with a self-lubricating layer and can be extended to the conformal contact problem of spherical contact surfaces in biomechanics and other fields.Originality/valueThe model presented here overcomes the limitations of the elastic half-space and small deformation assumptions. It accurately calculates the contact pressure distribution of self-lubricating spherical bearings. Moreover, the complex nonlinear relationship between variables such as normal force, clearance, maximum contact pressure and contact radius was investigated using this model. The model can also be extended and applied to the conformal contact problem of spherical contact surfaces in various fields, including biomechanics.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0296/

Role of viscoelasticity in the adhesion of mushroom-shaped pillars

The contact behaviour of mushroom-shaped pillars has been extensively studied for their superior adhesive properties, often inspired by natural attachment systems observed in insects. Typically, pillars are modeled with linear elastic materials in the literature; in reality, the soft materials used for their fabrication exhibit a rate-dependent constitutive behaviour. Additionally, conventional models focus solely on the detachment phase of the pillar, overlooking the analysis of the attachment phase. As a result, they are unable to estimate the energy loss during a complete loading-unloading cycle.
This study investigates the role of viscoelasticity in the adhesion between a mushroom-shaped pillar and a rigid flat countersurface. Interactions at the interface are assumed to be governed by van der Waals forces, and the material is modeled using a standard linear solid model. Normal push and release contact cycles are simulated
at different approaching and retracting speeds.
Results reveal that, in the presence of an interfacial defect, a monotonically increasing trend in the pull-off force with pulling speed is observed. The corresponding change in the contact pressure distribution suggests a transition from short-range to long-range adhesion, corroborating recent experimental and theoretical investigations.
Moreover, the pull-off force remains invariant to the loading history due to our assumption of a flat-flat contact interface. Conversely, in the absence of defects and under the parameters used in this study, detachment occurs after reaching the theoretical contact strength, and the corresponding pull-off force is found to be rate
independent. Notably, the hysteretic loss exhibits a peak at intermediate detachment speeds, where viscous dissipation occurs, which holds true in both the presence and absence of a defect. However, the presence of a defect shifts the region where the majority of viscous dissipation takes place.

A Contact Mechanics Model for Surface Wear Prediction of Parallel-Axis Polymer Gears.

As surface wear is one of the major failure mechanisms in many applications that include polymer gears, lifetime prediction of polymer gears often requires time-consuming and expensive experimental testing. This study introduces a contact mechanics model for the surface wear prediction of polymer gears. The developed model, which is based on an iterative numerical procedure, employs a boundary element method (BEM) in conjunction with Archard's wear equation to predict wear depth on contacting tooth surfaces. The wear coefficients, necessary for the model development, have been determined experimentally for Polyoxymethylene (POM) and Polyvinylidene fluoride (PVDF) polymer gear samples by employing an abrasive wear model by the VDI 2736 guidelines for polymer gear design. To fully describe the complex changes in contact topography as the gears wear, the prediction model employs Winkler's surface formulation used for the computation of the contact pressure distribution and Weber's model for the computation of wear-induced changes in stiffness components as well as the alterations in the load-sharing factors with corresponding effects on the normal load distribution. The developed contact mechanics model has been validated through experimental testing of steel/polymer engagements after an arbitrary number of load cycles. Based on the comparison of the simulated and experimental results, it can be concluded that the developed model can be used to predict the surface wear of polymer gears, therefore reducing the need to perform experimental testing. One of the major benefits of the developed model is the possibility of assessing and visualizing the numerous contact parameters that simultaneously affect the wear behavior, which can be used to determine the wear patterns of contacting tooth surfaces after a certain number of load cycles, i.e., different lifetime stages of polymer gears.

Lesion Size Location Dependency on Maximum Pressure in Osteochondral Defects: Experiments and Finite-Element Analysis.

Osteochondral defects (OCDs) in the knee joint have significant clinical implications, particularly regarding contact pressures and pressure distribution. Understanding how these factors are influenced by defect size and location is crucial for developing effective therapeutic strategies. The purpose of this study was to investigate the impact of defect size and location on contact pressures and pressure distribution in the knee joint. It was hypothesized that an increase in defect size would result in elevated contact pressures and alterations in pressure distribution, with specific variations related to defect location. Descriptive laboratory study. The study utilized 6 cadaveric knees, including the patella and fibula, subjected to controlled compressive loading for measuring contact pressures. Simultaneously, computed tomography-based models were created for finite-element analysis (FEA) to investigate the impact of varying defect sizes and locations on contact pressures and pressure distribution in the knee joint, excluding the patellofemoral joint. The study employed analysis of variance to assess contact pressure and defect size association. Comparison between medial and lateral femoral condyles at full extension and 30° flexion angle was performed, followed by post hoc testing. Fisher exact test analyzed peak pressure point location and defect size, categorizing them into medial and lateral. An increase in defect size corresponded with heightened contact pressures on both medial and lateral femoral condyles at full extension (P = .013 for medial and P = .024 for lateral). However, this correlation did not yield significant differences at 30° of flexion (P = .674 for medial and P = .333 for lateral). During mechanical testing, the highest pressures occurred near 5 mm defect dimensions. FEAs showed a significant increase in pressure and circumferential-edge stress with 7-mm defects. Peak contact pressure points shifted laterally with more significant defects. Our study demonstrated the impact of defect size, location, and alignment on knee joint contact pressures. Intervening promptly with defects exceeding 3 mm is crucial, as significant stress levels manifest beyond this threshold. Significant increases in contact pressures were noted with larger defect sizes, particularly between 3 and 10 mm at full extension. Peak pressure points shifted with defect size increments, and alignment variations showed minimal stress variation at 30° compared with 0°. FEA validated increasing contact pressures up to 7 mm defect size, beyond which pressures stabilized or slightly decreased. A concentrated pressure distribution on the medial side was observed. These findings inform our understanding of the biomechanical implications of OCDs. In the field of sports medicine, this research offers valuable insights to clinicians and researchers, elucidating key factors influencing knee joint health and the potential consequences of OCDs.

Research on the clearance evolution of preloading filling spiral case and surrounding concrete

Abstract The embedment of steel spiral cases within concrete under a pressurized condition is a kind of construction approach that widely used in pump-turbines. There will be an initial preloading clearance between the spiral case and surrounding concrete after the construction. The clearance is directly determined by the preloading water head and changes with the variation in operational hydraulic pressure, which will effect the combined load transmission mechanism. This paper investigates the clearance evolution of preloading filling spiral cases and surrounding concrete under different internal pressure. The effect of the preloading water head on the initial clearance, the contact characteristics and the combined load transmission mechanism under different internal pressure are numerically studied. The results show that the initial clearance between the spiral case and concrete increases with the rise of the preloading water head. The maximum clearances are all located at the waist of the spiral case. The clearance during operation presents uneven distribution characteristics in spatial and temporal scales. Before the internal water pressure comes to the preloading water head, the inlet, outer part in the direction of 45° and the sectional area are the first to close, the outer part of the waist follows, while the outer area of the spiral case middle remains open when the pressure reaches the preloading water head. The contact pressure distribution is consistent with the contact status characteristic. The conclusion of this paper aims to improve the understanding of the effect of the clearance between the preloading filling spiral case and concrete, so as to provide theoretical reference for safe and stable operation of pump-turbine units.

Examining Pipe–Borehole Wall Contact and Pullback Loads for Horizontal Directional Drilling

Pipeline pullback load is a crucial basis for drill rig selection and pipeline strength design. This paper presents a new pullback load calculation model from the perspective of pipe–borehole wall contact. The pipe–borehole wall contact analysis includes the distribution of contact pressure and the relationship between the external load and compressive displacement. The friction force between the pipe and the borehole wall was calculated based on the pipe–borehole wall contact analysis and adhesion theory without depending on the empirical friction coefficient. The effects of the eccentricity were also considered when calculating the fluid drag force. Through case studies, we verified the applicability of the model and discussed the possible reasons for the errors between the theoretical and field-measured results. This study can provide a helpful tool for analyzing the pipe–borehole wall contact and pullback loads for horizontal directional drilling.

Axisymmetric Hertzian contact problem accounting for surface tension and strain gradient elasticity

In this paper, we investigate the axisymmetric Hertzian contact problem at micro-/nanoscale. The deformation of material bulk is described by a simplified theory of strain gradient elasticity, and the influence of surface tension is integrated based on the surface elasticity theory. Using the Mindlin's potential function method and double Fourier integral transform, the normal surface displacement induced by a concentrated force is derived in a closed form. Following this, the contact between a rigid sphere and an elastic half-space is formulated in terms of singular integral equation, which is numerically solved by applying the Gauss-Chebyshev method. The results indicate that the distribution of contact pressure is distinctly different from that in classical elasticity theory. The indented substrate tends to perform stiffer due to the effects of surface tension and strain gradient elasticity. When the contact radius is comparable with the material length parameter, the indentation force (depth) can be ten (three) times of that given by classical Hertz theory.

Load Distribution After Serial Resection of the Posterior Horn of the Lateral Meniscus and Subsequent Meniscal Allograft Transplant: A Biomechanical Study

Background: Data are lacking as to when a meniscal allograft transplant (MAT) may be biomechanically superior to a partially resected lateral meniscus. Hypothesis: Lateral MAT using a bone bridge technique would restore load distribution and contact pressures in the tibiofemoral joint to levels superior to those of a partial lateral meniscectomy. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen human cadaveric knees were evaluated in 5 lateral meniscal testing conditions (native, one-third posterior horn meniscectomy, two-thirds posterior horn meniscectomy, total meniscectomy, MAT) at 3 flexion angles (0°, 30°, and 60°) under a 1600-N axial load. Pressure sensors were used to acquire contact pressure, contact area, and peak contact pressure within the tibiofemoral joint. Results: Limited (one-third and two-thirds) partial lateral posterior horn meniscectomy showed no significant increase in mean and peak contact pressures as well as no significant decrease in contact area compared with the intact state. Total meniscectomy significantly increased mean contact pressure at 0° and 30° (P = .008 and P < .001, respectively), increased peak contact pressure at 30° (P = .04), and decreased mean contact area in all flexion angles compared with the native condition (P < .01). Lateral MAT significantly improved mean contact pressure compared with total meniscectomy at 0° and 30° (P = .002 and P = .003, respectively) and increased contact area at 30° and 60° (P = .003 and P = .009, respectively), although contact area was still significantly smaller (24.1%) after MAT relative to the native meniscus (P = 0.015). However, allograft transplant did not result in better tibiofemoral contact biomechanics compared with limited partial meniscectomy (P > .05). Conclusion: The peripheral portion of the lateral meniscus provided the most important contribution to the distribution of contact pressure across the tibiofemoral joint in the cadaveric model. Total meniscectomy significantly increased mean and peak contact pressure in the cadaveric model and decreased contact area. Lateral MAT restored contact biomechanics close to normal but was not superior to the partially meniscectomized status. Clinical Relevance: Surgeons should attempt to preserve a peripheral rim of the posterior lateral meniscus. Meniscal allograft transplant appears to improve but not normalize mean contact pressure and contact area relative to total lateral meniscectomy.

Study on the bending behavior of CFRP-confined square concrete-filled steel tubes reinforced with internal latticed steel angles

The bending mechanical properties of FRP-confined square concrete-filled steel tubes (CFST) reinforced with internal latticed steel angles, including the failure modes, characteristic curves and characteristic mechanical parameters of tested specimens, were investigated through experiments in this paper. The bending mechanisms were also analyzed using an established finite element model, including the analysis of the bending moment borne by each component, the distributions of contact pressure between different components at the mid-span section, and the distributions of the neutral axis under the bending capacity. The key influential parameters, including the tensile strength and thickness of the FRP, were also examined. The results indicate that the FRP has almost no influence on bending stiffness, however, it enhances the yield bending moment and bending capacity to a certain extent. It was also found that the enhancement decreases as the width of steel tube increases, and the influence of FRP is more profound before reaching the peak load. The calculation formulas for the bending capacity were developed using the superposition method and numerical fitting method. Analysis of their accuracy shows that the formulation using the superposition method yields relatively accurate and safe prediction results, with the prediction errors of less than 20 %.

Equal heat flux loading optimization approach for uniform wear of the wet brake

Due to their exceptional ability to endure heavy loads, cam-lobe radial-piston hydraulic motors are extensively utilized in heavy machinery. The wet brake is a key part capable of providing highly braking torque, which has numerous friction pairs and a compact structure. However, there exists a challenge in solving the issue of irrational pressure distribution which leads to non-uniform heat flux distribution and severe wear failure of the brake discs. For this, an innovative method to optimize the wet brake's loading structure has been developed to address the issue of non-uniform heat flux distribution. A thermomechanical coupling finite element (FE) model was established to establish a clear correlation between loading structure parameters and contact pressure distribution on the brake disc. An innovative equal heat flux criterion was introduced to guide the optimization process. Simulation results confirmed that the optimized loading structure achieved a brake disc contact pressure distribution aligned with the ideal heat flux density criteria. Experimental validation further demonstrated a notable reduction of up to 44.39 % in maximum wear depth (hmax) across different radii of the brake disc compared to the unoptimized structure. These findings underscore the efficacy of our approach in reducing wear rates and enhancing durability of the wet brakes.

Sealing Performance Evaluation and Structural Optimization for Reducing Leakage Failures of Lip Seal Considering High-Speed Rotation Frictional Heat

This article proposes a high-speed rotating thermo-solid coupling finite element model for a lip seal that simulates the lip temperature changes during rotation by cyclically applying thermal loads to achieve lip temperature distribution characteristics. Considering the influence of working condition parameters and structural parameters, the lip temperature and sealing interface contact pressure distribution are obtained, and the lip seal structure is optimized. The results show that ignoring the uneven distribution of lip friction heat will lead to a 25.6% error in the radial force. The optimized lip seal yields an impressive 14.3% reduction in leakage rate compared to the original configuration, showcasing a significant performance enhancement in lip seal.

Nonlinear dynamic response of a sandwich plate with negative Poisson’s ratio honeycomb-core layer under low-velocity collision impact

In this paper, a nonlinear analytical model is presented for the low-velocity collision impact of a sandwich plate with auxetic honeycomb-core layer. The auxetic feature of the honeycomb material is realized by mathematically expressing the effective material coefficients in terms of material property and cellular geometric parameters through a homogenization method. The higher order shear deformation theory, the von Kármán nonlinearity theory, and a modified Hertz contact law which accounts for the contact pressure distribution and indentation effect, are employed to establish the kinematic relations. The Newmark time integration scheme in conjunction with the direct iterative method is utilized to establish a solution procedure for the nonlinear dynamic governing equation. The verification of the presented model with the data in published literatures is carried out, followed by a series of numerical analyses for influences of cellular geometric features and impactor’s initial conditions (such as impactor’s initial velocity, mass, and nose curvature radius) on the nonlinear dynamic response. The results of numerical analyses show that the geometric features of the unit cell in the honeycomb-core and impactor’s initial conditions can cause significant influences on the nonlinear collision impact behaviors of the system.