Buckling and wrinkling of thin structures often lead to very complex response curves that are hard to follow by standard path-following techniques, especially for very thin membranes in a slack or nearly slack state. Many recent papers mention numerical difficulties encountered in the treatment of wrinkling problems, especially with path-following procedures and often these authors switch to pseudo-dynamic

After the recent publications on the design of deployable structures with straight scissors, it has been shown that the possibilities in the application of this type of structure are enormous: organic geometries, bistability control, etc. However, one of the aspects that have still not been studied is the particular case of using identical elements. On the one hand, the satisfaction of this geometric

The paper presents a novel approach for analytic modeling and numerical analysis of spatial problems of thermoelasticity for isotropic solids containing thread-like nondeformable inhomogeneities. The inhomogeneity is removed from consideration as a geometric object, and its influence on the continuum is replaced by sought functions (of heat flux and mechanical forces) distributed along some line (the

This paper presents an extension of Castigliano’s second theorem for orthotropic beams. The notion “extension” in this context means to find more accurate results not only for the vertical deflection, but also for the horizontal deflection and the rotation angle. For this purpose the Airy stress function is calculated for an orthotropic rectangular strip based on the iterative approximation method

The mechanical behaviour of structural elements made of 3D-printed materials is numerically investigated. With this aim a multiscale approach that allows to determine the macroscopic response, as depending on the material heterogeneity at the microscale level, is conceived. A non-linear laminate finite element that employs a reduced homogenization technique at each integration Gauss point is developed

Heterogeneous materials can show size-dependent behaviour in which the bending modulus depends on sample size. In fibre composite materials the interaction between fibre and matrix can lead to such a size effect.Then the effective modulus calculated by the rule of mixtures can either underestimate or overestimate the bending modulus of the laminate, depending on the fibre/matrix material mismatch,

The plane problem of a loaded Euler-Bernoulli beam of finite length in frictionless bilateral contact with a microstructured half-plane modelled by the couple stress theory of elasticity is considered here. The study is aimed to investigate the size effects induced on the beam internal forces and moments by the contact pressure and couple stress tractions transmitted across the contact region. Use

This paper describes a boundary-element-based approach for the modeling and solution of potential problems that involve thin layers of varying curvature. On the modeling side, we consider two types of imperfect interface models that replace a perfectly bonded thin layer by a zero-thickness imperfect interface across which the field variables undergo jumps. The corresponding jump conditions are expressed

This paper investigates the compression behaviour of engineered-plastic-plate reinforced elastomeric isolators (EPPREIs), which use engineered plastic plates instead of steel reinforcements as in conventional isolators. Compared to the latter, EPPREIs are cheaper, lighter and easier to install. Experimental tests showed that EPPREIs can undergo different types of failure: buckling, delamination and

In this work, a thermodynamically consistent constitutive framework is introduced that is capable of reproducing the significant time-dependent behaviour of austenite-to-bainite phase transformations. In particular, the aim is to incorporate the effect of these diffusion-controlled processes by plasticity-like evolution equations instead of incorporating related global diffusion equations. To this

Linearly viscoelastic constitutive theories are usually expressed as a Prony series involving fourth order tensors and retardation times. Obtaining the numerical values of the terms involved in such constitutive models from experiments is an ill-posed problem in the sense that many parameter sets can adequately fit experimental data. Considering that the computational time involved in the simulation

Fiber-based materials are prevalent in nature and in engineering applications. Microscopically, these materials resemble a discrete assembly of crosslinked or entangled fibers. To understand the relationship between the effective mechanical properties and the underlying microstructures, we consider a variety of periodic and random two-dimensional (2D) networks of crosslinked long fibers. The linearly

The mechanical behavior at contact points in high-voltage electrical cable conductors is simulated to find where damage may occur. The presented approach is based on a numerical model that is referred to as the wire model. The critical zones are detected by simulating the mechanical behavior of a cable conductor section with a large number of contacts. For the wire model, a relevant regularized contact

Cyclotetramethylene-Tetranitramine (HMX) is a secondary explosive used in military and civilian applications. Its plastic deformation is of importance in the initiation of the decomposition reaction, but the details of plasticity are not yet fully understood. It has been recently shown that both the elastic constants and the critical resolved shear stress for plastic deformation are pressure sensitive

This paper presents a two-dimensional interface model for timber-concrete contacts, that has been developed based on the empirical observations from a set of friction tests and additional micromechanical assumptions. In tangential direction, the interface model accounts initial bonding and debonding between the surfaces, different static and kinetic friction as well as smooth transition between them

We deal with the detection and shape reconstruction of inclusions in elastic bodies based on a monotonicity method and aim to reconstruct them with experimental measurements. Thus, we base our studies on the rigorously proven theory of the linearized monotonicity tests for noisy measurement data, where the so-called Neumann-to-Dirichlet operator, its Fréchet derivative and the corresponding monotonicity

In this contribution, a small strain single crystal plasticity framework in the context of an infeasible primal-dual interior point method (IPDIPM) is discussed with a focus on the numerical treatment. Related to rate-independent algorithms in the field of single-crystal plasticity, the use of the IPDIPM to solve the constrained optimization problem offers the advantage that it handles the naturally

Closed-cell materials, such as plate-lattices, are attracting increasing attention as a result of their potential to achieve the theoretical upper bounds for isotropic elasticity and strain energy storage (the Hashin-Shtrikman upper bounds) (Berger et al., 2017). However, their complex meso-geometries, especially their enclosed structures, make most of additive manufacturing methods impossible to undertake

A continuum damage model is proposed capturing the influence of damage on the stress tensor for ductile steel sheets under multiaxial loading conditions. The model consists of a critical strain, representing damage initiation, as well as a failure strain. Both are Hosford-Coulomb type functions of the triaxiality and the Lode parameter. In order to prevent the pathological mesh-sensitivity for continuum

The indentation of a microcapsule with a spherical indenter is an effective technique to evaluate the elastic properties of microcapsule shells. The spherical indentation of a microcapsule could be modelled as a microsphere with core–shell structure indented by a rigid sphere. Based on the assumption that the deformed pattern of microcapsule is axisymmetric at small indentation displacement, the deformed

This paper presents a multi-temporal series high-accuracy numerical manifold method (NMM) for fracture analysis of solid materials under highly time-dependent thermal loadings. In the present method, the framework of NMM is used to perform space discretization of the thermo-mechanical coupling system, due to its advantages in accurately calculating field variables and describing discontinuity. An explicit

In composite laminates the layer-wise material mismatch induces highly localized stress concentrations at the free edges. This is referred to as free-edge effect. As a consequence interlaminar crack initiation may occur in addition to the typically considered intralaminar failure modes. The stresses do not necessarily have to be caused by mechanical loads. Also temperature differences may induce significant

Recently, origami structures have been widely studied for various applications such as mechanical, electrical, bio, and nanosystems. Unlikely paper-like materials, engineering materials have higher stiffness and thickness so the hinge-like motion of the crease of paper origami is impossible. Therefore, origami, which is not made of paper-like materials, has different characteristics from paper origami

In architecture and engineering, surfaces with positive Gaussian curvature such as domes are used for their high stiffness-to-weight ratios and efficiency in enclosing a volume. These curved shapes are difficult to create due to time-consuming or scale-limited processes. In recent years, origami and kirigami have risen as viable routes for the rapid fabrication of complex surfaces from flat sheets;

This study analyzes the finite deformation and the bifurcation behavior associated with the opening (i.e., unbending and eversion) of a bilayered cylinder, with layers made of hyperelastic and incompressible materials. The solution to the finite deformation problem reveals interesting stress states, including the presence of multiple neutral axes, as well asin certain cases the absence of neutral axes

Adhesive bonding community shows a continued interest in using bridging mechanisms to toughen the interface of secondary bonded joints, especially in the case of laminated composites. Due to snap-back instability that occurs during fracture, confusions may exist when identifying the toughening effect experimentally. The true toughening effect may be overestimated by lumping all energy contributions

The present paper proposes a new Strain Energy Function (SEF) for incompressible transversely isotropic hyperelastic materials, i.e. materials with a single fiber family. This SEF combines polyconvex invariants forming an integrity basis (Ta et al., 2014) in a polynomial and exponential form. Compared to a previous attempt for building a SEF based on the same invariants (Cai et al., 2016), we have

Multinetwork (MN) is a common topological structure in polymerization related manufacturing and artificial high-performance polymers. Currently the experimental and theoretical researches of MNs are generally focused on the deformation and failure mechanism of self-dissimilar tough hydrogels or tough elastomers, in which the topological structures of each sub network are significantly different. In

In the present work, an elastoplastic-damage model fully coupled with the constitutive equations of the non-associated plasticity is developed, to enrich the existing research results on the non-associated plasticity finite element models. The yield function and the plastic potential are represented independently by two different (Hill, 1948) quadratic functions to describe the anisotropic behavior

This paper proposes a new 3D continuous-discontinuous heat conduction model to consider the thermal resistance effect of cracks and dynamic crack propagation during heat transfer. Combining this heat conduction model and the finite-discrete element method (FDEM), we construct a coupled thermomechanical model for solving thermal cracking problems in brittle materials. The mechanical fracture calculation

Due to the existence of cracks and defects in composite materials during the manufacturing process, damage and crack growth in these materials must be anticipated before application. In the present research, an efficient theoretical mixed mode I/II fracture criterion is proposed for fracture investigation of orthotropic materials considering the effects of non-singular stress term in William’s series

We present a theory for finite and spatial elastic deformation of rods under the influence of arbitrary magnetic field and boundary condition. The rod is modeled as a Kirchhoff rod and is assumed to have uniformly distributed array of uniaxial spheroidal paramagnetic inclusions embedded in it all pointing in the same direction in the undeformed state. The governing equations of the magnetoelastic rod

This work presents a novel approach to efficiently model anodic dissolution in electrochemical machining. Earlier modeling approaches employ a strict space discretization of the anodic surface that is associated with a remeshing procedure at every time step. Besides that, the presented model is formulated by means of effective material parameters. Thereby, it allows to use a constant mesh for the entire

This article presents a simple progressive damage model for quasi-brittle materials, combining orthotropic elasticity with a scalar damage model including spatial variation of the damage initiation strain and the crack band method for softening regularization. The model’s performance is first analyzed from a numerical point of view and then demonstrated for tensile tests (0°,45° and 90°), open-hole

Under tensile loadings, thin-walled structures such as sheet metal and tubes develop load maxima, or limit loads, beyond which deformation localizes leading to rupture. For uniform stress states, Considère-type estimates of limit loads can serve as forming limits in applications. The paper explores the effect of anisotropy on such estimates for thin-walled Al-alloy tubes under combined tension and

The purpose of this article is to model defect nucleation. The defect is considered as a small volume which evolves as a damaged zone. The damage is described by a transition zone which can be sharp or continuous. In the first case, discontinuities occur and the initiation of defect is based on bifurcation of an equilibrium state. When the transition is continuous, the initiation of the defect is continuous

This paper revisits the topic of mean field homogenization for short fiber reinforced composite materials. A short glass fiber reinforced thermoplastic polyamide 6.6 with a fiber mass fraction of 35% is used as an example material for which microstructural analyses and experimental tests were performed. We cover a set of common models: the Self-Consistent (SC), Mori-Tanaka (MT), Ponte Castañeda-Willis

This paper investigates the behaviour of an underwater elastic toroidal shell storage container filled with compressible fluid under constraint volume condition. The fundamental form of the surface is used to define the geometry of a toroidal shell under an initial unstrained state (IUS), reference state (RS), and deformed state (DS). In the reference state, it is assumed that the toroidal shell storage

In small-scale mechanical tests, such as micropillar compression tests, plastic deformation is often localized in narrow slip traces. These slip traces result from a few dislocation sources with relatively low nucleation stresses that are present in the material. In order to accurately simulate such small-scale experiments, the stochastics of the underlying dislocation network must be taken into account

Starting from the exact solution of the heterogeneous linear viscoelastic Eshelby ellipsoidal inclusion problem obtained in the time domain for an ellipsoidal inclusion embedded in an isotropic matrix (Berbenni et al., 2015), a direct time-incremental homogenization Mori-Tanaka scheme for two-phase non linear elasto-viscoplastic materials is proposed. The extension to non-linear behavior is based on

The aim of the article is mathematical modeling of behavior of hyper viscoelastic particulate reinforced composite materials. Three dimensional hyper viscoelastic constitutive equations, which include an inherent damage parameter and its functions, have been developed. The model was used to demonstrate physical phenomenon such as the so called dewetting effect. New strain rate, damage rate and stress

Corrugated structures are made up of panels with periodic profiles. These are used as a compliant mechanism and as core in sandwich plates for their direction dependent stiffness. Modeling and large deflection analysis of corrugated structure play an essential role in their design and application. This work proposes an iterative scheme for the large deflection analysis of double corrugated cantilever

Data on the room temperature behavior of titanium is limited. To assess the anisotropy of the plastic behavior of a commercially pure grade 2 hcp–titanium T40 for different strain paths, in this study both uniaxial tests in various orientations with respect to the rolling direction as well as bulging tests using different die apertures were conducted. Under uniaxial tension, the plastic anisotropy

Ductibor® 500-AS is a hot-stamping steel that has been designed to introduce local ductile regions within hot-stamped tailor-welded blanks (TWBs) used for energy-absorbing sections of automotive structures. This study investigates the flow and fracture behavior of a range of the microstructures of this alloy, corresponding to mostly ferritic (∼ 96% ferrite plus 4% martensite), intermediate ferritic

We develop in this paper a general asymptotic homogenization model pertaining to magnetoelectric shells and sandwich shells composed of an arbitrary distribution of reinforcements or actuators attached to the surface of a thin shell or sandwiched between two shells. The constituents of the reinforced shells are orthotropic and may exhibit piezoelectric and/or piezomagnetic behavior. A set of twenty

Dynamic failure behaviors of fully clamped and simply supported composite sandwich beams with stepwise gradient foam cores subject to low-velocity impact have been investigated experimentally. The sandwich beams with uniform foam core, positive-gradient foam core and negative-gradient foam core are designed and manufactured. The experimental results show that the mass distributions of cores have significant

Many composites and their constituents exhibit strength difference (SD) effects. To reduce the computational cost associated to twoscale simulations, the theory of nonuniform transformation field analysis (NTFA, originally proposed by Michel and Suquet, 2003) is extended to consider a general case of SD effects in elastoplasticity, containing several well-known plasticity models like von Mises or Drucker

The unique mechanical properties and transport features of grain boundaries (GBs) in polycrystalline materials have been widely investigated. However, studies which focus on the unique chemo-mechanics phenomena resulting from GBs’ are exceedingly sparse. In this work, a thermodynamically consistent framework has been developed to explore the multi-physics coupling between mechanics and species diffusion

This paper describes the development of a dual-actuator loading device that was then used to apply asymmetric, transverse end-displacements to laminated beam specimens (silicon/epoxy/silicon) over a range of separation rates. Measurements of the reaction forces, as well as load-point displacements and rotations, were used to determine the normal and tangential components of the crack tip displacements