Hertzian Indentation Research Articles

Improving contact damage resistance of spinel translucent ceramics through a multi-layer design

The brittle response of transparent spinel ceramics to contact damage is limiting their application as an alternative to glasses and single crystals. In this work, we explore a strategy to enhance the contact damage resistance of spinel ceramics by embedding alumina layers in a multi-layer architecture. Crack initiation upon Hertzian indentation was investigated in MgAl2O4 – Al2O3 laminates and compared to their corresponding monoliths. Contact stresses during loading were analyzed using finite element simulations by considering the elastic properties of the layers and contact non-linearities. Results were analyzed using Weibull statistics. It was found that the effect of in-plane residual stresses on crack formation in the laminate depends on the disposition of the compressive spinel layers, either at the surface or embedded in the structure. Embedding alumina between spinel layers increased the load-bearing capability before crack initiation by ~70% compared to spinel, offering a promising approach to enhance contact damage resistance.

Bulk and fracture process zone contribution to the rate-dependent adhesion amplification in viscoelastic broad-band materials

The contact between a rigid Hertzian indenter and an adhesive broad-band viscoelastic substrate is considered. The material behavior is described by a modified power law model, which is characterized by only four parameters, the glassy and rubbery elastic moduli, a characteristic exponent n and a timescale τ0. The maximum adherence force that can be reached while unloading the rigid indenter from a relaxed viscoelastic half-space is studied by means of a numerical implementation based on the boundary element method, as a function of the unloading velocity, preload and by varying the broadness of the viscoelastic material spectrum. Through a comprehensive numerical analysis we have determined the minimum contact radius that is needed to achieve the maximum amplification of the pull-off force at a specified unloading rate and for different material exponents n. The numerical results are then compared with the prediction of Persson and Brener viscoelastic crack propagation theory, providing excellent agreement. However, comparison against experimental tests for a glass lens indenting a PDMS substrate shows data can be fitted with the linear theory only up to an unloading rate of about 100μm/s showing the fracture process zone rate-dependent contribution to the energy enhancement is of the same order of the bulk dissipation contribution. Hence, the limitations of the current numerical and theoretical models for viscoelastic adhesion are discussed in light of the most recent literature results.

Effect of elastic gradients on the fracture resistance of tri-layer restorative systems

ObjectivesTo assess the impact of elastic gradients formed among restorative material, cement, and substrate on the fracture resistance of tri-layer restorative systems. MethodsFour CAD/CAM materials were utilized, two glass-ceramics (IPS e.max CAD, Vita Suprinity) and two resin-ceramic hybrids (Vita Enamic, Lava Ultimate). Their fracture resistance was examined by biaxial flexure (n = 8) and Hertzian indentation (n = 10) tests. Statistical analysis was conducted using ANOVA and Tukey tests (p = 5 %). Finite element analysis (FEA) was employed to simulate the Hertzian indentation test and elucidate the stress-fields formed on the intaglio surface below the loading area. ResultsThe biaxial flexural strength (MPa) of glass-ceramics exceeded the hybrid materials (e.max 417a, Suprinity 230b, Enamic 138c, and Lava Ultimate 183bc). Conversely, the load-bearing capacity (N) of the materials bonded to dentin analog demonstrated the opposite trend, with the hybrid materials achieving superior results (e.max 830 C, Suprinity 660D, Enamic 1822B, and Lava Ultimate 2593 A). The stress-fields observed by FEA were coherent with the experimental results for Hertzian flexural stresses (MPa): e.max 501 A, Suprinity 342 C, Enamic 406B, whereas no tensile stress was observed at the intaglio surface of Lava Ultimate. SignificanceDetailed analysis of the fracture resistance of the tri-layer restorative systems showed that the elastic gradients play a more significant role than the flexural strength of the restorative materials. The coherence of the elastic moduli between the restorative material and supporting structures results in reduced tensile stress concentration at the intaglio surface beneath the loading area and enhances the ability to withstand load.

Revealing ‘invisible’ subsurface structural change/damage in silicate glass made by ‘nearly-elastic contact’ with a spherical smooth surface

This research delves into the hypothesis that elastic contact with an external object can generate `invisible' surface defects, consequently reducing the apparent load to failure, or strength, of glass. This theory, while longstanding, has left the intricate details associated with such defects largely unknown. Utilizing vibrational spectroscopic techniques—with a depth sensitivity on the order of approximately 100 nm—and chemical etching, the study investigates subsurface structural alterations in and around the area subjected to nominally-elastic contact with a Hertzian indenter. Direct contact with the spherical indenter led to the recovery of over 99.96 % of the surface topography, suggesting a near-perfect post-indentation surface. However, surface-sensitive vibrational spectroscopy unveiled structural changes in the subsurface silicate network. Additionally, a shift in the vibrational spectrum was observed in areas that had experienced elastic deformation along with the contact region and fully recovered upon unloading. This shift indicates residual structural changes, even in these non-contacted regions. When the indenter tip was slid across the surface under loads much lower than the nominal yield strength, interfacial friction made the top-most region more susceptible to base-catalyzed hydrolysis. The depth affected by friction was significantly shallower than the length scale of the principal stress fields at maximum load during Hertzian indentation. Despite the glass surface maintaining its microscopic defect-free appearance, these subsurface structural changes—induced by indentation and friction—are proposed to be key factors responsile for the decrease in the apparent load to failure of glass.

Hertzian crack propagation in graded glass/ceramic composites

AbstractIn literature, the concept of material gradation is shown to inhibit surface crack initiation in glass/ceramic composites subjected to Hertzian indentation. However, surface cracks could yet initiate due to relatively higher loadings or in the presence of surface flaws/defects. Hence, characterization of graded composites concerning the resistance against Hertzian crack initiation and propagation manifests itself as a prominent matter. In this study, axisymmetric Hertzian cracks evolving in graded glass/ceramic composites propelled by a rigid cylindrical punch are investigated employing a novel recursive method, called the stacked‐node propagation procedure. Crack trajectories and their propagation susceptibilities are predicted via the minimum strain energy density (MSED) criterion regarding the crack growth resistance (R‐curve) of ceramics. The stress trajectory approach is also considered for a homogeneous glass to reveal the reliance and effectiveness of the MSED criterion in the present crack problems. The Mori–Tanaka relations are adopted to model the elastic modulus and Poisson's ratio variations through the composites, which are implemented on the simulations via the homogeneous finite element approach. Hertzian crack problem of a practically producible graded composite comprised of oxynitride glass and a fine‐grained silicon nitride ceramics (Si3N4) is treated as a case study. The degree of material gradation is assessed for the mitigation of surface crack initiation and propagation risks.

Effect of twist on indentation resistance

With mechanical metamaterials that display force-torque coupling receiving recent attention, we tested the effect of twist on indentation resistance. We hypothesised that the force required to indent a twisting lattice to a set depth would increase with the amount of transverse deformation caused by twist. Based on previous work, various chiral lattices were designed to twist by up to 1.3° per 1 % compression. These lattice designs were 3D-printed in Nylon-12, then tested, with the experiments replicated in finite element simulations. Indentation resistance increased with twist; the lattice with maximum twist required ∼70 % higher indentation force (when normalised to compressive stiffness) than the non-twisting (antichiral) one during spherical indentations to 1 % of sample thickness. Further, we calculate the expected effects of twist on indentation resistance by combining the established micropolar and Willis’ plane stress moduli with classical Hertzian indentation equations. We found reasonable agreement (within 10 %) between 2D calculation methods use here and previous 3D calculation methods. The indentation resistance calculated using the micropolar plane stress modulus followed the same trends as the simulations and experiments. The calculated indentation force was within 10 % of the simulations and experiments.

Investigating the mechanical behaviour of Fukushima MCCI using synchrotron Xray tomography and digital volume correlation

A primary target towards the clean-up operation of the Fukushima disaster is the retrieval of Molten Core-Concrete Interaction (MCCI) products, presently residing on the basement of the damaged nuclear reactor Units 1–3. MCCI is a fusion of materials, composed of both nuclear fuel cladding and neighbouring structural components. Determining the currently unknown, physical and mechanical properties of MCCI is essential for successful and timely retrieval. In this paper, we aim to experimentally quantify the mechanical properties of a material fabricated to resemble MCCI. A small-scale representative specimen was mechanically tested using Hertzian indentation stepwise loading. Synchrotron X-ray computed tomography was conducted at several loading stages to reveal the sample microstructure and mechanical degradation. The acquired tomograms were analysed by digital volume correlation to measure full-field displacements and strains developed within the sample volume. Young’s modulus and Poisson ratio were determined via this combined methodology.

Crack nucleation and propagation in the phase-field cohesive zone model with application to Hertzian indentation fracture

Hertzian indentation fracture (Hertz, 1896) is an intriguing problem with no pre-defects. Recent studies indicated that those popular phase-field models for brittle fracture might be restrictive in dealing with this problem — crack nucleation can be considered only for the failure strength within a rather limited range. In this work, this problem is analyzed by the phase-field cohesive zonde model (PF-CZM), focusing on the whole failure process of crack nucleation and propagation. Analytical and numerical results show that for any realistic failure strength, the ‘spontaneous’ crack nucleation in an initially defect-free surface, the subsequent small but rapid vertical extension and finally the stable cone-shaped crack propagation, etc., can all be qualitatively and quantitatively captured by the PF-CZM with no modification. This competence is credited to treating the failure strength and the fracture energy (toughness) as two independent material properties. Accordingly, the phase-field length scale is a numerical parameter of no further constraint, which can be made as small as possible such that the convergence to the Barenblatt (1959) cohesive zone model is guaranteed even for short cracks. Moreover, the seamless incorporation of the strength-based crack nucleation criterion and the energy-based crack propagation criterion endows the PF-CZM with the capability of tackling crack nucleation and propagation in pristine solids.

Cyclic contact fatigue behavior of baria-silicate glass-ceramics as a function of crystal aspect ratio

Ceramic materials are potentially useful for dental applications because of their esthetic potential and biocompatibility. However, evidence of contact fatigue damage in ceramics raises considerable concern regarding its effect on the survival probability predicted for dental prostheses. To simulate intraoral conditions, Hertzian indentation loading with steel indenters was applied in this study to characterize the fatigue failure mechanisms of ceramic materials. Baria silicate glasses and glass-ceramics with different aspect ratios of crystals were selected because the glass and crystal phases have similar density, elastic modulus, and thermal expansion coefficients. Therefore, this system is a model ceramic for studying the effect of crystal geometry on contact cyclic fatigue failure. The subsequent flexural strength results show that the failure of materials with a low fracture toughness such as baria-silicate glass (0.7 MPa m1/2) and glass-ceramic with an aspect ratio of 3.6/1 (1.3 MPa m1/2) initiated from cone cracks developed during cyclic loading for 103 to 105 cycles. The mean strengths of baria-silicate glass and glass-ceramics with an aspect ratio of 3.6/1 decreased significantly as a result of the presence of a cone crack. Failures of baria-silicate glass-ceramics with an aspect ratio of 8.1/1 (Kc = 2.1 MPa m1/2) were initiated from surface flaws caused by either grinding or cyclic loading. The gradual decrease of fracture stress was observed in specimens with an aspect ratio of 8.1/1 after loading in air for 103 to 105 cycles. A reduction of approximately 50 % in fracture stress levels was found for specimens with an aspect ratio of 8.1/1 after loading for 105 cycles in deionized water. Thus, even though this glass-ceramic with an 8.1/1 crystal aspect ratio material is tougher than that with a 3.6/1 crystal aspect ratio, the fatigue damage induced by a large number of cycles is comparable. The mechanisms for cyclic fatigue crack propagation in baria-silicate glass-ceramics are similar to those observed under quasi-static loading conditions. An intergranular fracture path was observed in glass-ceramics with an aspect ratio of 3.6/1. For an aspect ratio of 8.1/1, a transgranular fracture mode was dominant.

Contact fatigue of WC-6%wtCo cemented carbides: Influence of corrosion-induced changes on emergence and evolution of damage

The effect of corrosion-induced changes on the contact fatigue response and associated damage in a medium-grained WC-6%wtCo hardmetal grade is investigated. Cyclic contact loading tests are conducted by means of Hertzian indentation techniques. Corrosion damage is introduced in a controlled way by previous immersion of specimens in a stirred acidic medium. Results reveal that corrosion significantly affects the contact fatigue behavior of the material under consideration, in terms of decreasing the effective load bearing capability of the material as well as earlier emergence and evolution of specific damage features, as compared to those discerned under monotonic loading and in a pristine hardmetal respectively. As cycle number increases, damage evolution in the corroded condition is more gradual and diffuse than for the uncorroded one. In general, it is dominated by existence of ill-defined radial cracks together with pronounced carbide grain pull-out which finally evolve into cohesive-like spallation in regions close to the periphery of indentation imprints. These findings are rationalized on the basis of phase assemblage changes linked to corrosion, particularly in terms of lessening of toughening capability and easiness of WC grain pull-out intrinsic to the loose and porous binderless WC skeleton remnant at the surface level, after exposure to the acid medium. Although some removal of carbide grains and discrete cohesive chipping is also observed in the pristine sample for very high number of cycles, such different response, as compared to monotonic loading, is linked to oxidation phenomena of the metallic binder for this reference condition.

Effect of Graphene Enrichment on Solid Particle Erosion Performance of Electroless Ni-P Composite Coatings

Abstract Solid particle erosion (SPE) and dents (from contact loads) are among numerous surface degradations in the hydrocarbon industry that can in turn compromise the longevity of protective coatings. Both these degradation mechanisms can induce cracks that allow the corrosive solutions to seep through those cracks and corrode the underlying metal, thereby defeating the purpose of surface protection. Nickel-phosphorus (Ni-P) coatings have been known for decades for their corrosion resistance, but their applications in hydrocarbon industries are impeded by their tribological limitations, namely low wear resistance. In the current research work, graphene nanoplatelets were introduced to an Ni-P electroless plating bath in various concentrations (30 mg/L, 60 mg/L, and 100 mg/L) to achieve three different compositions of ternary Ni-P–graphene coatings, namely Ni-P-30 mg G, Ni-P-60 mg G, and Ni-P-100 mg G, respectively. Surface roughness was characterized via topography employing a laser confocal microscope. Coating hardness was characterized using Vickers hardness and the composition analyses were carried out via energy dispersive spectroscopy. SPE was conducted via Tungsten carbide (WC) erodent ball at three different impact angles and two different particle velocities. Finally, Hertzian indentation was performed under two different loads to characterize the denting behavior of coatings. Eroded and dented coatings were further visualized via an optical microscope. The highest concentration of graphene (by 18 vol.%) in Ni-P-30 mg G coating improved the hardness, leading to the smallest size of indents during both SPE and Hertzian indentation. Also, Ni-P-30 mg G exhibited no evidence of cracking under normal impact angle and particle velocities of 35 ms−1 and 52 ms−1.

Effects of acid leaching treatment of soda‐lime silicate glass on crack initiation and fracture

AbstractWater or acid soaking surface treatments have been shown to increase the mechanical strength of soda‐lime silicate (SLS) glasses. This increase in strength has traditionally been attributed to effects related to residual stress or changes in fracture resistance. In this work, we report experimental data that cannot be explained based on the existing knowledge of glass surface mechanics. In dry environments, annealed and acid‐leached SLS surfaces have comparable crack initiation stress and fracture stress as measured by Hertzian indentation and biaxial bending tests, respectively. Yet, in the presence of humidity, acid‐leached surfaces have higher failure stress than the annealed surfaces. This apparent enhancement in the crack resistance of the acid‐leached surface of SLS glass in humid environments supports the hypothesis that acid‐leached surface chemistry can lower the transport kinetics of molecular water to critical flaws.

Investigating the Microstructure and Mechanical Behavior of Simulant ‘Lava-Like’ Fuel Containing Materials From the Chernobyl Reactor Unit 4 Meltdown

Decommissioning of the damaged Chernobyl nuclear reactor Unit 4 is a top priority for the global community. Before such operations begin, it is crucial to understand the behavior of the hazardous materials formed during the accident. Since those materials formed under extreme and mostly unquantified conditions, modelling alone is insufficient to accurately predict their physical, chemical and, predominantly, mechanical behavior. Meanwhile, knowledge of the mechanical characteristics of those materials, such as their strength, is a priority before robotic systems are employed for retrieval and the force expected from them to be exerted is one of the key design questions. In this paper we target to measurement of the standard mechanical properties of the materials formed during the accident by testing small-scale, low radioactivity simulants. A combined methodology using Hertzian indentation, synchrotron X-ray tomography and digital volume correlation (DVC), was adopted to estimate the mechanical properties. Displacement fields around the Hertzian indentation, performed in-situ in a synchrotron, were measured by analyzing tomograms with DVC. The load applied during the indentation, combined with full-field displacement measured by DVC was used to estimate the mechanical properties, such as Young’s modulus and Poisson’s ratio of these hazardous materials.

Investigating the microstructure and mechanical behaviour of simulant “lava-like” fuel containing materials from the Chernobyl reactor unit 4 meltdown

Decommissioning of the damaged Chernobyl nuclear reactor Unit 4 is a top priority for the global community. Before such operations begin, it is crucial to understand the behaviour of the hazardous materials formed during the accident. Since those materials formed under extreme and mostly unquantified conditions, modelling alone is insufficient to accurately predict their physical, chemical and, predominantly, mechanical behaviour. Meanwhile, knowledge of the mechanical characteristics of those materials, such as their strength, is a priority before robotic systems are employed for retrieval and the force expected from them to be exerted is one of the key design questions. In this paper we target to measurement of the standard mechanical properties of the materials formed during the accident by testing small-scale, low radioactivity simulants. A combined methodology using Hertzian indentation, synchrotron X-ray tomography and digital volume correlation (DVC), was adopted to estimate the mechanical properties. Displacement fields around the Hertzian indentation, performed in-situ in a synchrotron, were measured by analysing tomograms with DVC. The load applied during the indentation, combined with full-field displacement measured by DVC was used to estimate the mechanical properties, such as Young's modulus and Poisson's ratio of these hazardous materials.

Influence of CAD/CAM milling, sintering and surface treatments on the fatigue behavior of lithium disilicate glass ceramic

This paper reports on the process-fatigue relation of lithium disilicate glass ceramic (LDGC) using low-cycle, high-load Hertzian indentations with a rigid indenter to simulate teeth grinding/clenching of LDGC restorations with different surface asperities obtained in CAD/CAM milling, sintering, polishing and glazing. The maximum contact stresses were evaluated as functions of the number of load cycles and surface treatments using the Hertzian model. Indentation-induced surface damage was viewed using scanning electron microscopy (SEM) to understand the relationships among microstructures, surface asperities, crack morphology and propagation. Different processes and surface treatments significantly affected the maximum contact stresses of indented LDGC surfaces (ANOVA, p < 0.05), which were all significantly reduced with the number of cycles (ANOVA, p < 0.05). Quasi-plastic deformation was dominant in single-cycle indentation of all processed and treated surfaces. In higher cycle indentations, inner cone cracks were formed on all surfaces; median and transverse cracks were formed on the roughest surfaces processed by CAD/CAM milling and sintering. Ring cracks, fretting, pulverization, micro-bridges, surface smearing and wedging, and edge chippings were also propagated on all surfaces. The process-fatigue relation provides an understanding of the mechanical functions of surface asperities produced in different processes and treatments. It indicates that the mechanically assisted growth of surface asperities with different roughness strongly affected the indentation-induced surface damage. Finally, the smoothest surfaces produced by CAD/CAM milling, polishing and sintering sustained the highest contact stresses and the least fatigue damage at higher cycles, ensuring their superior fatigue performance compared to other processed LDGC surfaces.

Friction Influenced by Vibrations: A Refined Contact-Mechanics View on Lateral and Rotational Oscillations

It is known that superposed movements can lower the friction felt at the macroscale. This is well documented for in-plane and normal translatory oscillations. Contact mechanics are a suitable approach to model this effect but so far have not gone beyond single-slider dynamics. In this study, we make use of 3D Boundary Elements Simulations to study the macroscopic friction reduction. This approach allows us to take into account also partial sliding of the contact zone. We first revisit the case of transversal in-plane translatory oscillations. Here, we argue that the behavior at small velocities can best be described when partial slip is indeed taken into account. Next, we investigate the frictional response of a Hertzian indenter when the lateral movement is superposed with a rotational bore movement. An analytical approximation is given for the steady state solution with constant angular velocity. The third case under investigation is an oscillating bore rotation. We present numerical results for the reduction of the macroscopic friction. In two limiting cases, an analytical prediction is given, following the lines used in the translatory case. For extremely large amplitudes, it is based on the idea that a rotational steady state is assumed at every instant. For small velocities we adapt our new approach including partial sliding. We find these predictions to be good but not perfect, slightly underestimating the reduction that rotational oscillations can provide.

Corrosion-induced changes on Hertzian contact damage in cemented carbides

In this study, the influence of corrosion on the mechanical response and damage induced under Hertzian indentation is assessed for three cemented carbides with metallic binders of different chemical nature. Corrosion degradation is introduced in a controlled way, before subsequent spherical indentation testing, by immersing specimens in a stirred acidic medium. Results reveal quite strong corrosion effects on indentation stress-strain response and contact damage scenario. Such detrimental influence is found to be dependent on both the ratio between indentation depth and thickness of the corroded layer as well as chemical nature of the binder. In this regard, critical loads for emergence and evolution of specific damage events (i.e. ring and radial cracks, and even specimen failure) are proposed as figures of merit for material selection under the combined action of corrosion and contact loads. Within this context, the hardmetal grade with Co-base binder and addition of Cr is found to be the best option, among the three cemented carbides studied in this investigation. It points out the consideration of the synergic interaction between corrosion resistance and hardness/toughness correlation for microstructural design optimization of hardmetals under service-like conditions. These statements are supported by the relevant corrosion-induced changes also observed, by means of advanced characterization techniques, in terms of deformation/failure micromechanisms at both surface and subsurface levels.

Hertzian Indentation Behavior of Electroless Ni-P-Ti Composite Coatings

Ni-P-Ti composite coatings have been prepared by co-depositing Ni-P and nano-Ti particles which were then annealed. Tensile tests were conducted on standalone coatings to acquire the mechanical properties of the coatings without the effect of the steel substrate. The Hertzian indentation tests were performed on coating-steel substrate bilayer systems to investigate the indentation behavior of the coatings. After annealing, Ni3Ti and superelastic NiTi phases are identified in composite coatings by XRD and EDS. Compared to the as-deposited Ni-P coatings, the toughness of the annealed composite coatings improved significantly. The superelastic effect of NiTi particles was observed in the Hertzian indentation behavior of the annealed composite coatings. The strengthening mechanisms as well as toughening mechanisms such as crack bridging, crack deflection, crack arresting, and transformation toughening were discussed. Recovery ratio (η) values as well as Hertzian indentation stress distribution were computed to analyze and explain the indentation behavior of the as-deposited and annealed coatings.

Double-layer gradient MoSi2-borosilicate glass coating prepared by in-situ reaction method with high contact damage resistance and interface bonding strength

High emissivity coating is an important part of spacecraft thermal protection system. MoSi2-borosilicate glass coatings prepared by the in-situ reaction method showed excellent thermal endurance and oxidation resistance. However, radial cracks were prone to appear under external forces due to high cohesive of in-situ reaction dense coatings, and few studies focused on the mechanical properties of gradient coatings. In this study, a double-layer gradient MoSi2-borosilicate glass coating with a porous interface layer and a dense surface layer was prepared on mullite fibrous insulation tiles by in-situ reaction method. The double-layer gradient coating was compared with a mono-layer dense coating and a high-density gradient coating (another gradient coating with higher interface layer density) with reference to microstructure, contact damage resistance, interface bonding strength and thermal shock resistance. Compared with mono-layer dense coating and high-density gradient coating, double-layer gradient coating showed higher bearing capacity and avoided radial crack initiation and propagation in Hertzian indentation test. Besides, the double-layer gradient coating endured the most thermal shock cycles between 1500 °C and 20 °C and presented substrate fracture instead of interface fracture. In addition, double-layer gradient coating and high-density gradient coating possessed much higher interface bonding strengths than mono-layer dense coating. The total emissivities of three coatings were all greater than 0.87. The porous interface in double-layer gradient coating presented the advantages in enhanced mechanical and thermal compatibility between the in-situ reaction dense coating and substrate through reducing elastic modulus and thermal expansion coefficient differences.

Peridynamic modelling of Hertzian indentation fracture

Hertzian indentation technique is a method that is widely used in the investigation of the fracture toughness and the Young’s modulus of a brittle material. Thus, it has been studied in various research studies during the past century. The problem describes axisymmetric fracture behaviour of a flaw-free brittle solid under compression due to the impact of a stiff indenter. During the fracture process, the evolution of the crack is divided into two stages. Initially, a ring crack forms spontaneously outside the contact region under a critical load. Then, it propagates for a small distance perpendicular to the free surface of the brittle solid. With the increase in load applied on the indenter, a cone-shaped crack occurs at the bottom of the ring flaw and it grows at a certain angle. Hence, in this study a new numerical technique, peridynamics, is utilised to analyse the historical complex fracture problem. To reduce the computational time, the problem is simplified by considering an axisymmetric model. The effect of Poisson’s ratio on the orientation and size of the cone-shaped crack are investigated.