Ramarathnam Narasimhan

Indian Institute of Science | IISC · Department of Mechanical Engineering

The objective of this work is to investigate the three-dimensional nature of stationary mode I notch tip fields in a basal-textured magnesium alloy. To this end, crystal plasticity based finite element analyses are performed pertaining to a four-point bend fracture specimen for two notch orientations. In the first orientation, the notch and line pe...

Fatigue pre-cracked four-point bend specimens of a rolled AZ31 Mg alloy are loaded asymmetrically and their mixed-mode (I and II) fracture behaviour is contrasted with pre-notched samples. In-situ mapping of displacement and strain fields is performed through optical imaging coupled with digital image correlation analysis. The fracture surface morp...

Mode I, static fracture experiments and uniaxial tension/compression tests are conducted at three temperatures in the range from 25 to 100∘C using fatigue pre-cracked four-point bend and micro-tensile/compression specimens machined from a rolled AZ31 Mg alloy plate. Digital image correlation technique along with in-situ optical imaging is employed...

Crystal plasticity based finite element (CPFE) simulations employing Taylor homogenization for a basal-textured Mg alloy are performed under plane strain, small scale yielding (SSY) conditions to study mixed-mode (I and II) notch tip fields. Two notch orientations are considered. In one case, the notch line and normal to the flat surfaces of the no...

In this work, plane strain finite element and atomistic simulations of tensile response of double edge notched bulk metallic glass composite (BMGC) samples are conducted. A special constitutive model is used to represent the response of the bulk metallic glass matrix along with J 2 flow theory of plasticity to characterize the crystalline dendrites...

In this study, finite element analyses of Mode I loading of stationary cracks in in-situ bulk metallic glass composites (BMGCs) are performed under plane strain, small scale yielding (SSY) conditions. In the first part of this work, a thermodynamically consistent finite strain constitutive theory for BMGCs is employed to represent the entire domain...

Mixed-mode (I/II) fracture experiments on rolled AZ31 Mg alloy are conducted using notched four point bend specimens along with in-situ imaging. Digital Image Correlation (DIC) technique is used to analyze the images and map out the deformation and strain fields. With increase in mode II component of loading, a monotonic reduction in the notched fr...

A method for evaluating the contributions from mode I and II components of loading to the energy release rate J in ductile asymmetric four-point bend (4-PB) specimens is proposed. The validity of the method is established by conducting elastic-plastic finite element analysis of several asymmetric 4-PB specimens exhibiting a range of mode mixities f...

It has been observed that tension twins (TTs) are triggered in rolled polycrystalline magnesium alloys under tensile loading applied along the rolling direction (RD) or the transverse direction. This is surprising because these alloys have a near-basal texture, and TTs would therefore cause extension (instead of contraction) along the normal direct...

In this work, numerical simulations using molecular dynamics and non-local plasticity based finite element analysis are carried out on tensile loading of nano-scale double edge notched metallic glass specimens. The effect of acuteness of notches as well as the metallic glass chemical composition or internal material length scale on the plastic defo...

In this work, plane strain finite element simulations of cylindrical void growth ahead of a notch tip in Mg single crystals are conducted to understand the effects of lattice orientation and crack tip constraint on the ductile fracture processes. The constitutive response is represented through crystal plasticity theory accounting for both slip and...

Continuum finite element analyses are performed to ascertain the role played by the volume fraction (Vf) and strain hardening behavior of crystalline reinforcements on the strength and ductility of bulk metallic glass matrix composites (BMGCs). Results show that a highly strain hardening elongated dendrite with Vf ~ 45% would make the BMGC ductile...

Brittle metallic glasses exhibit a unique and intriguing fracture morphology of periodic nanocorrugations whose spacing and amplitude are of the order of tens of nanometers. We show through continuum simulations that they fail by spontaneous and simultaneous cavitation within multiple weak zones arising due to intrinsic atomic density fluctuations...

In this work, growth of cylindrical voids corresponding to different stress states in Mg single crystal under plane strain conditions is analyzed using a crystal plasticity based finite element procedure which accounts for twinning through a quasi-slip approximation. Two lattice orientations are considered with the c-axis along the thickness in one...

Recent experiments have shown that nano-sized metallic glass (MG) specimens subjected to tensile loading exhibit increased ductility and work hardening. Failure occurs by necking as opposed to shear banding which is seen in bulk samples. Also, the necking is generally observed at shallow notches present on the specimen surface. In this work, contin...

In this work, Mode-I fracture experiments are conducted using notched compact tension specimens machined from a rolled AZ31 Mg alloy plate having near-basal texture with load applied along rolling direction (RD) and transverse direction (TD). Moderately high notched fracture toughness of JC ∼ 46 N/mm is obtained in both RD and TD specimens. Fractur...

Significant progress in understanding the mechanical behavior of metallic glasses (MGs) was made over the past decade, particularly on mechanisms of plastic deformation. However, recent research thrust has been on exploring the mechanics and physics of fracture. MGs can be very brittle with \(K_{Ic}\) values similar to silicate glasses and ceramics...

In this work, the mode I fracture response of a rolled Mg AZ31 alloy is investigated by conducting experiments using notched compact tension specimens. It is found that the notched fracture toughness Jc ∼ 42 N/mm which is moderately high. Detailed examination using EBSD and optical metallography indicates that profuse tensile twinning occurs almost...

Mode I fracture experiments were conducted on brittle bulk metallic glass (BMG) samples and the fracture surface features were analyzed in detail to understand the underlying physical processes. Wallner lines, which result from the interaction between the propagating crack front and shear waves emanating from a secondary source, were observed on th...

Using a thermodynamically consistent non-local plasticity model, the mechanistic origin of enhancement in ductility and suppression of dominant shear banding in nanoglasses (NGs) is analysed. It is revealed that the interaction stress between flow defects plays a central role in promoting global plasticity of NGs. Specifically, we find that the int...

Recent experiments using three point bend specimens of Mg single crystals have revealed that tensile twins of {1012}-type form profusely near a notch tip and enhance the fracture toughness through large plastic dissipation. In this work, 3D finite element simulations of these experiments are carried out using a crystal plasticity framework which in...

Experimental studies and atomistic simulations have shown that brittle metallic glasses fail by a cavitation mechanism whose origin has been traced to the presence of intrinsic atomic density fluctuations which give rise to weak zones with reduced yield strength. It has been shown recently through continuum analysis that the presence of these zones...

In this work, the fracture behavior of magnesium single crystals is studied by conducting experiments with notched three point bend specimens of three crystallographic orientations. In the first and second orientations, the c-axis is along the normal to the flat surface of the notch, while in the third it is aligned with the notch front. For all th...

Several experimental studies have shown that fracture surfaces in brittle metallic glasses (MGs) generally exhibit nanoscale corrugations which may be attributed to the nucleation and coalescence of nanovoids during crack propagation. Recent atomistic simulations suggest that this phenomenon is due to large spatial fluctuations in material properti...

A combined 3D finite element simulation and experimental study of interaction between a notch and cylindrical voids ahead of it in single edge notch (tension) aluminum single crystal specimens is undertaken in this work. Two lattice orientations are considered in which the notch front is parallel to the crystallographic [101¯] direction. The flat s...

Recent experimental studies have revealed nanoscale cavities and periodic corrugations on the fracture surfaces of brittle metallic glasses. How such cavitation in these materials leads to brittle failure remains unclear. Here we show, using atomistic and continuum finite element simulations, that a shear band can mediate cavity nucleation and coal...

The objectives of this paper are to study the effects of plastic anisotropy and evolution in crystallographic texture with deformation on the ductile fracture behaviour of polycrystalline solids. To this end, numerical simulations of multiple void growth and interaction ahead of a notch tip are performed under mode I, plane strain, small scale yiel...

Some bulk metallic glasses (BMGs) exhibit high crack initiation toughness due to shear band mediated plastic flow at the crack tip and yet do not display additional resistance to crack growth due to the lack of a microstructure. Thus, at crack initiation, the fracture behavior of BMGs transits from that of ductile alloys to that of brittle ceramics...

The importance of air bearing design is growing in engineering. As the trend to precision and ultra precision manufacture gains pace and the drive to higher quality and more reliable products continues, the advantages which can be gained from applying aerostatic bearings to machine tools, instrumentation and test rigs is becoming more apparent. The...

In recent years, cohesive zone models have been employed to simulate fracture and delamination in solids. This paper presents in detail the formulation for incorporating cohesive zone models within the framework of a large deformation finite element procedure. A special Ritz-finite element technique is employed to control nodal instabilities that m...

In this work, the effects of loading rate, material rate sensitivity and constraint level on quasi-static crack tip fields in a FCC single crystal are studied. Finite element simulations are performed within a mode I, plane strain modified boundary layer framework by prescribing the two term (K − T) elastic crack tip field as remote boundary condit...

We perform atomistic simulations on the fracture behavior of two typical metallic glasses, one brittle (FeP) and the other ductile (CuZr), and show that brittle fracture in the FeP glass is governed by an intrinsic cavitation mechanism near crack tips in contrast to extensive shear banding in the ductile CuZr glass. We show that a high degree of at...

In this work, the effect of impact loading on mode I stationary crack tip fields in a three point bend FCC single crystal fracture specimen is investigated using plane strain finite element analysis. The behavior of the single crystal is assumed to be elastic-perfectly plastic. The main objective is to examine the role of material inertia in influe...

In this work, the effect of lattice orientation on the fields prevailing near a notch tip is investigated pertaining to various constraint levels in FCC single crystals. A modified boundary layer formulation is employed and numerical solutions under mode I, plane strain conditions are generated by assuming an elastic–perfectly plastic FCC single cr...

Effect of constraint (stress triaxiality) on void growth near a notch tip in a FCC single crystal is investigated. Finite element simulations within the modified boundary layer framework are conducted using crystal plasticity constitutive equations and neglecting elastic anisotropy. Displacement boundary conditions based on mode I, elastic, two ter...

An efficient algorithm within the finite deformation framework is developed for finite element implementation of a recently proposed isotropic, Mohr–Coulomb type material model, which captures the elastic–viscoplastic, pressure sensitive and plastically dilatant response of bulk metallic glasses. The constitutive equations are first reformulated an...

In this paper, modes I and II crack tip fields in polycrystalline plastic solids are studied under plane strain, small scale yielding conditions. Two different initial textures of an Al–Mg alloy, viz., continuous cast AA5754 sheets in the recrystallized and cold rolled conditions, are considered. The former is nearly-isotropic, while the latter dis...

Stationary crack tip fields in bulk metallic glasses under mixed mode (I and II) loading are studied through detailed finite element simulations assuming plane strain, small scale yielding conditions. The influence of internal friction or pressure sensitivity on the plastic zones, notch deformation, stress and plastic strain fields is examined for...

In this paper, an overview of some recent numerical simulations of stationary crack tip fields in elastic–plastic solids is presented. First, asymptotic analyses carried out within the framework of 2D plane strain or plane stress conditions in both pressure insensitive and pressure sensitive plastic solids are reviewed. This is followed by discussi...

The near-tip deformation field in a high-constraint three-point bend specimen of pure aluminium single crystal is studied using in situ electron back-scattered diffraction and optical metallography. The orientation considered has the notch lying on the (0 1 0) plane and the notch front along direction. Results clearly show the occurrence of a kink...

In this work, effects of pressure sensitive yielding and plastic dilatancy on void growth and void interaction mechanisms in fracture specimens displaying high and low constraint levels are investigated. To this end, large deformation finite element simulations are carried out with discrete voids ahead of the notch. It is observed that multiple voi...

The objective of this work is to study the growth of a cylindrical void ahead of a notch tip in ductile FCC single crystals under mode I, plane strain, small scale yielding (SSY) conditions. To this end, finite element simulations are performed within crystal plasticity framework neglecting elastic anisotropy. Attention is focussed on the effects o...

In this work, two families of asymptotic near-tip stress fields are constructed in an elastic-ideally plastic FCC single crystal under mode I plane strain conditions. A crack is taken to lie on the (010) plane and its front is aligned along the [[`1]01]{[\overline{1}01]} direction. Finite element analysis is first used to systematically examine the...

A study of the effect of Poisson’s ratio on the stationary mode I crack tip fields in amorphous alloys is conducted. Finite element simulations under plane strain, small scale yielding conditions are performed with a Mohr–Coulomb based constitutive model that accounts for pressure sensitivity of plastic flow as well as the localization of plastic s...

In this work, the effect of crack tip constraint on near-tip stress and deformation fields in a ductile FCC single crystal is studied under mode I, plane strain conditions. To this end, modified boundary layer simulations within crystal plasticity framework are performed, neglecting elastic anisotropy. The first and second terms of the isotropic el...

We report a combined experimental and computational study of a low constraint aluminum single crystal fracture geometry and investigate the near-tip stress and strain fields. To this end, a single edge notched tensile (SENT) specimen is considered. A notch, with a radius of 50 μm, is taken to lie in the (010) plane and its front is aligned along th...

In this work, the effect of constraint on void growth near a notch tip under mode-I loading is investigated in materials exhibiting pressure sensitive yielding and plastic dilatancy. To this end, large deformation elastic–plastic finite element analyses are performed using a two-dimensional (2D) plane strain, modified boundary layer formulation by...

In this work, the mechanics of tubular hydroforming under various types of loading conditions is investigated. The main objective is to contrast the effects of prescribing fluid pressure or volume flow rate, in conjunction with axial displacement, on the stress and strain histories experienced by the tube and the process of bulging. To this end, ax...

In this work, stationary crack tip fields in amorphous materials such as metallic glasses under mode I loading are studied to understand the factors that control crack tip plasticity and in turn impart toughness to those materials. For this purpose, finite element simulations under plane strain, small scale yielding conditions are performed. A cont...

In this paper, a finite element study of 3D crack tip fields in pressure sensitive plastic solids (such as polymers or metallic glasses) under mode I, small scale yielding conditions is performed. The material is assumed to obey a small strain, Extended Drucker–Prager yield condition. The roles of pressure sensitive yielding, plastic dilatancy and...

In this paper, the fracture behavior of a thin hard film, perfectly bonded to a soft substrate, containing circumferential (cylindrical) cracks subjected to spherical indentation is studied using the finite element method. These cracks emanate upwards from the film–substrate interface and are driven by the flexure of the film over the soft substrat...

In this work, localized necking in aluminium alloy tubes subjected to free hydroforming is analyzed. The main objective is to study the influence of loading conditions, such as prescribed fluid pressure or volume flow rate in conjunction with axial end feed, on the nature of the forming limit curve (FLC). To this end, the strain histories experienc...

In this paper, finite element simulations of spherical indentation of a thin hard film deposited on a soft substrate are carried out. The primary objective of this work is to understand the operative mode of deformation of the film corresponding to various stages of indentation. The transition from contact dominant behaviour to that governed by fle...

  In this paper, the confined compression test set-up [Ma and Ravichandar (2000) Experimental Mechanics vol. 40, pp. 38–45] is employed to characterise the pressure-dependent yield behaviour of polymers. Attention is restricted to polymethyl methacrylate (PMMA) which is assumed to obey the Drucker–Prager yield function. The main objective is to dev...

The stress fields near a crack front in a ductile solid are essentially three-dimensional (3D) in nature. The objective of this paper is to investigate the structure of these fields and to establish the validity of two-dimensional (2D) plane stress and plane strain approximations near the crack front under mixed mode (combined modes I and II) loadi...

In this paper, an overview of computational studies on mixed-mode ductile fracture initiation (involving combination of modes I and II) is presented. These studies employ the Gurson constitutive model to represent the ductile fracture processes of micro-void nucleation, growth and coalescence and are carried out using a 2D plane strain boundary lay...

In this paper, a combined experimental and numerical investigation of free hydroforming of aluminium alloy tubes is conducted. The tubes are subjected to different loading histories involving axial compression and internal pressure. The circumferential and axial strains experienced by the tubes are continuously recorded along with the pressure and...

In this article, the time-dependent spherical indentation response of a linear, isotropic, viscoelastic material to different load histories is studied. To this end, finite element computations and depth-sensing microindentation experiments using polymethyl methacrylate specimens are undertaken. The validity of viscoelastic indentation theories is...

The objective of this paper is to apply the expanding cavity model to study the conical or spherical indentation response of hydrostatic pressure dependent plastic solids. To this end, the elastic–perfectly plastic stress and displacement fields in a hollow sphere subjected to internal pressure are first obtained by assuming that the material obeys...

Metallic glasses exhibit high hardness values, typified by a plastic constraint factor (the ratio of hardness to compressive yield strength) that is considerably larger than that seen in ductile crystalline metals. The reason for this behaviour is investigated in this paper, by conducting a combined experimental and numerical study on the spherical...

In this paper, finite element simulations of spherical indentation of a thin hard film deposited on a soft substrate are carried out. The primary objective of this work is to understand the mechanics of fracture of the film due to formation of cylindrical or circumferential cracks extending inwards from the film surface. Also, the role of plastic y...

In this paper, the effects of T-stress on steady, dynamic crack growth in an elastic–plastic material are examined using a modified boundary layer formulation. The analyses are carried out under mode I, plane strain conditions by employing a special finite element procedure based on moving crack tip coordinates. The material is assumed to obey the...

A recent numerical investigation (J. Mech. Phys. Solids 48 (2000) 1967) has demonstrated that ductile fracture specimens progressively lose constraint (or triaxiality Q) with increase in loading rate. The aim of the present paper is to examine whether the above phenomenon is responsible for the experimentally observed enhancement in dynamic fractur...

The objectives of this paper are to examine the loss of crack tip constraint in dynamically loaded fracture specimens and to assess whether it can lead to enhancement in the fracture toughness at high loading rates which has been observed in several experimental studies. To this end, 2-D plane strain finite element analyses of single edge notched (...

Polymeric adhesive joints are extensively employed in various industrial and technological applications. It has been observed that in ductile adhesive joints, interface fracture is a common mode of failure which may involve stable crack propagation followed by catastrophic growth. The objectives of this paper are to investigate the effects of bondl...

The objectives of this paper are to examine the validity of a two-parameter (J–Q) characterization of quasi-static crack tip fields in rate sensitive plastic solids and, also to investigate the influence of strain rate sensitivity of the material on the variation of fracture toughness with loading rate. To this end, 2D plane strain finite element a...

The objective of this paper is to study the evolution of T-stress in dynamically loaded fracture specimens. To this end, two-dimensional plane strain, elastodynamic finite element analyses of single edge notched (tension) specimens, and three point bend specimens subjected to time varying loads are performed. The T-stress is computed using an accur...

The objectives of this paper are to study the applicability of a two-parameter (J–Q) characterisation of the elastic–plastic crack tip fields in a dynamically loaded ductile specimen and to ascertain the effect of loading rate on the triaxiality parameter Q. To this end, 2D (plane strain) large deformation finite element analyses of a single edge n...

Polymeric adhesive layers are employed for bonding two components in a wide variety of technological applications. It has been observed that, unlike in metals, the yield behavior of polymers is affected by the state of hydrostatic stress. In this work, the effect of pressure sensitivity of yielding and layer thickness on quasistatic interfacial cra...

Polymeric ductile adhesive layers joining two elastic adherends is a common feature in various technological applications. Such joints can fail by ductile rupture involving interface debonding and void formation. It has been observed that, unlike in metals, the yield behaviour of polymers is affected by the state of hydrostatic stress. In the prese...

In this work a single edge notched plate (SEN(T)) subjected to a tensile stress pulse is analysed, using a 2D plane strain dynamic finite element procedure. The interaction of the notch with a pre-nucleated hole ahead of it is examined. The background material is modelled by the Gurson constitutive law and ductile failure by microvoid coalescence i...

In this paper, an overview of some recent computational studies by the authors on ductile crack initiation under mode I, dynamic loading is presented. In these studies, a large deformation finite element procedure is employed along with the viscoplastic version of the Gurson constitutive model that accounts for the micro-mechanical processes of voi...

In this work, the effect of constraint on hole growth near a notch tip in a ductile material under mode I and mixed mode loading (involving modes I and II) is investigated. To this end, a 2-D plane strain, modified boundary layer formulation is employed in which the mixed mode elastic K–T field is prescribed as remote boundary conditions. A finite...

In this work, the effect of constraint on ductile fracture process of microvoid growth and coalescence near a notch tip in a ductile material under mode I and mixed mode loading (involving modes I and II) is investigated. To this end, two sets of finite element simulations are carried out under two-dimensional plane strain conditions. In the first...

The effect of constraint on ductile fracture initiation from a notch tip under mode I and mixed mode (involving modes I and II) loading is investigated. To this end, mixed mode fracture experiments are performed with Compact Tension Shear (or CTS) specimen of a ductile 2014-O aluminium alloy. The constraint effects are investigated by considering s...

In this work, 2-D (plane strain) finiteelement analyses of a ductile three-point bend fracture specimen subjected to Mode I, dynamic (impact-like) loading are conducted. The initiation of a hole by debonding around a largeinclusion and its interaction with the notch tip is simulated. The background material isrepresented by the Gurson constitutive...

An interface fracture specimen for measuring the fracture toughness of adhesively bonded joints is proposed. It is found to represent a wide range of mode mixity. The specimen is calibrated assuming LEFM conditions and the limit of validity of this calibration as the load increases is also assessed.

The objective of this work is to study the mechanics of indentation of an adhesively bonded layered solid. To this end, several (plane strain) finite element simulations of wedge indentation of a ductile strip which is adhesively bonded to a rigid substrate are conducted by varying the properties of the adhesive layer. The stress fields below the i...

In this paper, steady, quasi-static crack growth under plane strain conditions in an elastic-plastic material subjected to mixed-mode loading (combined mode I and mode II) is analyzed. A modified small scale yielding formulation (Journal of the Mechanics and Physics of Solids, 1993, 41, 835–861) wherein the elastic K-field as well as the T-stress a...

A ductile metal layer joining two brittle ceramic blocks is a common architecture in engineering applications. The failure process of such a constrained ductile layer under mode I loading was studied in a previous work. In this paper, the effect of mode mixity on ductile rupture of the metal layer is investigated. A finite deformation, finite eleme...

The asymptotic mixed mode crack tip fields in elastic-plastic solids are scaled by the J-integral and parameterized by a near-tip mixity parameter, M _p . In this paper, the validity and range of dominance of these fields are investigated. To this end, small strain elastic-plastic finite element analyses of mixed mode fracture are first performed u...

In practical situations, the loading experienced at the tip of a crack or notch in a structural component could be very complex resulting in mixed-mode fracture. In recent years, several investigators (Tohgo et al., 1988; Aoki et al., 1990; Maccagno and Knott, 1992; Ghosal and Narasimhan, 1994) have studied mixed-mode ductile fracture initiation (i...

In this work, finite element simulations of the initiation of a void by debonding around a large, rigid inclusion and its interaction with a notch tip under mixed-mode loading involving Modes I and II are performed. The analyses are carried out under plane strain, small-scale yielding conditions. The background material is represented by the Gurson...

In this work, the asymptotic fields near a crack tip propagating dynamically under plane strain conditions at a ductile-brittle interface are derived. The ductile material is taken to obey the J2 flow theory of plasticity with linear isotropic strain hardening. The asymptotic solution is assumed to be of the variable-separable form with a power sin...

Numerical simulations of ductile fracture initiation caused by the interaction between a notch tip and a nearby hole under mixed-mode loading involving modes I and II are performed. Attention is restricted to plane strain, small-scale yielding conditions. The Gurson constitutive model that accounts for the ductile failure mechanisms of micro-void n...

In this work, steady, dynamic crack growth under plane strain, small-scale yielding conditions along a ductile-brittle interface is analysed using a finite element procedure. The ductile solid is taken to obey the J 2 flow theory of plasticity with linear isotropic strain hardening, while the substrate is assumed to exhibit linear elastic behaviou...

In this work, dynamic crack growth along a ductile-brittle interface under anti-plane strain conditions is studied. The ductile solid is taken to obey the J 2 flow theory of plasticity with linear isotropic strain hardening, while the substrate is assumed to exhibit linear elastic behavior. Firstly, the asymptotic near-tip stress and velocity field...

In this work, finite element simulations of mixed-mode (Modes I and II) fracture initiation in a ductile alloy with a dual distribution of second-phase particles are carried out under plane-strain, small-scale yielding conditions. The background material is represented by the Gurson constitutive model and strain controlled micro-void nucleation at...

Steady-state quasi-static crack growth along a bimaterial interface is analyzed under Mode III, small-scale yielding conditions using a finite element procedure. The interface is formed by an elastic-plastic material and an elastic substrate. The top elastic-plastic material is assumed to obey the J2 incremental theory of plasticity. It undergoes i...

In this work, two-dimensional (plane strain) finite element analysis of a ductile three-point bend fracture specimen subjected to mode I quasi-static and dynamic (impact-like) loading is conducted. The Gurson constitutive model that accounts for the ductile failure mechanisms of micro-void nucleation, growth and coalescence is employed within the f...

In this paper, an overview of some recent computational studies by the authors on mixed-mode ductile fracture initiation is presented. In these studies, mixed-mode ductile fracture involving Modes I and II was analyzed using the finite-element procedure within the context of plane strain, small-scale yielding conditions. The main objective of these...

A finite element simulation of frictionless wedge indentation of a copper strip has been carried out under plane strain conditions. The problem was first modelled using an one-pass contact algorithm. The difficulties associated with using this method to model wedge indentation problems are explained. An alternative procedure which alleviates some o...

A numerical study of the ductile rupture in a metal foil constrained between two stiff ceramic blocks is performed. The finite element analysis is carried out under the conditions of mode I, plane strain, small-scale yielding. The rate-independent version of the Gurson model that accounts for the ductile failure mechanisms of microvoid nucleation,...