Deformation In Different Directions Research Articles

Evaluation of plasticity and determination of deformation index of 3D-printed composite cement-based materials

ABSTRACT Given the current situation that the evaluation system of the deformation and instability failure of 3DPC is immature, this study was devoted to shaping the performance of 3DPC to provide new ideas and ways for exploring the stable forming of 3DPC. The relationship between the deformation in different directions and the number of layers was analysed. The deformation regulation of 3DPC was revealed, and the controllable index was determined. Results show that the vertical and horizontal deformation in the plastic state is correlated to evaluate the overall deformation by considering only the lateral deformation. The horizontal and vertical deformation of each layer decreases as the number of layers increases, forming a trapezoidal shape. The relationship between the horizontal deformation and the number of layers varies with the shape of the printed component. This relationship follows a linear pattern in the vertical direction and remains independent of the printing shape. The deformation process of 3DPC can be divided into three stages: linear deformation, elastoplastic, and plastic failure. The elastoplastic stage is identified as the primary stage, and the horizontal deformation begins here. Comparatively, the horizontal strain is more suitable for evaluating the plasticity of 3DPC than the vertical strain.

Study on strengthening and toughening mechanisms of Cu/Al composites dominated by interface layer

Cu/Al composites have the excellent properties of both Cu and Al, and have the properties of light weight and high conductivity, so they have been widely concerned. In this paper, 5-mm-thick Cu/Al composites prepared by the cast-rolling process are used as experimental materials. To reveal the strengthening and toughening mechanisms of the Cu/Al composites, the interfacial structure, micro-morphology, stress-strain condition, and GND distribution of Cu/Al composites before and after deformation were characterized utilizing TEM, TKD, and EBSD. The results show that the submicron intermetallic compounds Al2Cu and Al4Cu9 are formed from the casting-rolling Cu/Al composites. After 15% tensile deformation, many gaps occurred in the interface layer, but at the gaps, there was no crack spreading to the Cu and Al layers. Meanwhile, the deformation in different directions occurs in the Cu grains near the interface, forming a dislocation wall, and the entanglement of the dislocation occurs in the Cu layer near the interface, which contributes to the improvement of tensile strength. The Al layer near the interface layer produces kink bands, which helps to improve the ductility of the composites. Besides, due to the action of the hard intermetallic compound layer, with the increase in tensile deformation, a large number of GND are gradually accumulated in the Cu and Al layers near the interface, resulting in remote back stress, which makes the softer Cu and Al layers obtain higher strength. At the same time, the back stress caused by GND will induce strain hardening, which helps to maintain ductility, so that Cu/Al composites have higher plastic deformation ability while improving mechanical properties.

Anisotropic dynamic permeability model for porous media

Based on the tortuous capillary network model, the relationship between anisotropic permeability and rock normal strain, namely the anisotropic dynamic permeability model (ADPM), was derived and established. The model was verified using pore-scale flow simulation. The uniaxial strain process was calculated and the main factors affecting permeability changes in different directions in the deformation process were analyzed. In the process of uniaxial strain during the exploitation of layered oil and gas reservoirs, the effect of effective surface porosity on the permeability in all directions is consistent. With the decrease of effective surface porosity, the sensitivity of permeability to strain increases. The sensitivity of the permeability perpendicular to the direction of compression to the strain decreases with the increase of the tortuosity, while the sensitivity of the permeability in the direction of compression to the strain increases with the increase of the tortuosity. For layered reservoirs with the same initial tortuosity in all directions, the tortuosity plays a decisive role in the relative relationship between the variations of permeability in all directions during pressure drop. When the tortuosity is less than 1.6, the decrease rate of horizontal permeability is higher than that of vertical permeability, while the opposite is true when the tortuosity is greater than 1.6. This phenomenon cannot be represented by traditional dynamic permeability model. After the verification by experimental data of pore-scale simulation, the new model has high fitting accuracy and can effectively characterize the effects of deformation in different directions on the permeability in all directions.

CONSTRUCTIVE SOLUTIONS FOR EXPLOSION-RESISTANT BUILDINGS WITH CIVIL PROTECTION FACILITIES

In the conditions of the large-scale war led by russia in Ukraine, the issue of designingblast-resistant buildings with civil defense facilities that can withstand additional special loads and impacts has become crucial. These impacts include artillery and missile attacks, bomb explosions, blast waves, and the spread of fires, among others. An analysis of the consequences of building and structure destruction resulting from military operationsindicates that reinforced concrete structures of buildings have superior load-bearing capacity compared to traditional brick and steel frames of pavilion-type buildings.Reinforced concrete is a non-combustible material with significant mass, improving its inertialresistance. It possesses high strength and plasticity characteristics, allowing it to deform and redistribute forces between adjacent structures, thereby preventing progressive collapse – the cascading destruction of buildings.The main principles of designing blast-resistant reinforced concrete frames for high-rise buildings involve rational constructive systems and schemes with simple and compact configurations and symmetrical plans. The structural solution of the reinforced concrete frame must ensure the redistribution of gravity loads between adjacent structures. Therefore, the joints of vertical and horizontal structures must be plastic, capable of dissipating a significant amount of explosion energy. The load-bearing elements of buildingstructures must withstand cycles of large deformations in different directions, such aspressures from the lifting of floor slabs opposing ordinary gravity loads. For buildings classified with medium (CC2) and significant (CC3) consequences, where more than 50 individuals are constantly present or periodically more than 100 people, it is necessary to design civil protection premises. These premises should be strategically located below the planned ground level.The construction of civil protection premises located in the underground floors of an explosionproof building must withstand all types of main and episodic loads and impacts and resist the spread of fire. Building frames with monolithic reinforced concrete ribbed ceilings and systems of main and secondary beams or transversely located beams rigidly fixed to vertical supporting structures – columns, pylons, walls – can withstand such loadsbest. The article investigates the reasons for the destruction of reinforced concrete slabs in high-rise frame monolithic buildings when subjected to bending or pressure from explosive loads below. It also explores the potential twisting of the building as a result of reverse explosive effects.The article presents measures to strengthen sections of floor structures in high-rise framemonolithic buildings that may be destroyed due to reverse explosive loads and upward pressure from explosive forces. The expediency of reinforcing critical areas of monolithic reinforced concrete floor slabs with external reinforcement – adhering reinforcing mats in the form of fabrics, lamellas, or carbon fiber nets to the upper zones of slabs near vertical supports – is justified.

Influence of grasping postures on skin deformation of hand

To investigate the influence of different grasping postures on the hand’s skin deformation, a handheld 3D EVA SCANNER was used to obtain 3D models of 111 women in five postures, including a straight posture and grasping cylinders with various diameters (4/6/8/10 cm). Skin relaxation strain ratio (λp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{p}$$\\end{document}) and surface area skin relaxation strain ratio (λm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{m}$$\\end{document}) were used as measures of skin deformation between two landmarks and multiple landmarks, respectively. The effects of grasping posture on skin deformation in different directions were analyzed. The results revealed significant variations in skin deformation among different grasping postures, except for the width of middle finger metacarpal and the length of middle finger’s proximal phalanx. The λp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{p}$$\\end{document} increased with decreasing grasping object diameter, ranging from 5 to 18% on the coronal axis, and from 4 to 20% on the vertical axis. The overall variation of λm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{m}$$\\end{document} ranged from 5 to 37.5%, following the same trend as λp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\lambda }_{p}$$\\end{document} except for the surface area of tiger’s mouth, which exhibited a maximum difference of 10.9% with significant differences. These findings have potential applications in improving the design of hand equipment and understanding hand movement characteristics.

An isotropic zero Poisson's ratio metamaterial based on the aperiodic ‘hat’ monotile

Metamaterials are synthetic materials, engineered to have desirable mechanical properties. This paper is concerned with a class of cellular metamaterials that minimise the Poisson's ratio, a metric that characterises the deformation behaviour of materials according to their orthogonal response to applied force. This secondary deformation is usually visually apparent as a sideways “bulge”, and can limit the longevity of multi-material components, from aircraft parts to medical implants, because of the interference shear stresses that arise between different materials due to deformations in different directions by different amounts. As a result, low Poisson's ratio can be a desirable mechanical property and the challenge of producing cellular metamaterials that have reduced Poisson's ratio has received significant research attention. However, solutions that have been proposed tend to be limited in their applicability, either because they are anisotropic, so behaviour varies greatly according to direction of the applied force, or because they are very low in relative density, so have low stiffness. Here we introduce a new cellular metamaterial, a honeycomb based on the recently discovered aperiodic ‘hat’ monotile, which offers nominally zero Poisson's ratio. Results from compression testing and computational modelling show that the behaviour of this metamaterial is isotropic, and is consistent across a range of relative densities, leading to the exciting conclusion that zero Poisson's ratio is possible for different stiffnesses. We envisage that this metamaterial will facilitate otherwise unfeasible technologies, such as morphing wing structures and medical devices that better mimic the behaviour of tissues such as cartilage.

Quantification of inhomogeneity and anisotropy of bituminous mixtures using biaxial experimental data

Most of the existing mechanical characterization test methods and the analytical models for bituminous mixtures are developed based on the assumption of homogenous and isotropic material properties. However, the extent to which such assumptions hold good for bituminous mixtures is not very clear. A biaxial testing scheme in indirect tension mode can come in handy to collect the experimental data at different test temperature regimes. In this study, a bituminous mixture with a nominal maximum aggregate size (NMAS) of 13.2 mm is used to fabricate cylindrical test specimens with 150 mm diameter and 63.5 mm thickness for conducting the repeated load indirect tension (IDT) test. The input load level is selected as 5 to 13 % of the indirect tensile (ITS) failure load in the form of a haversine pulse of 0.1 s loading and 0.9 s rest period. Such loading is applied on zero-degree and ninety-degree orientations of the specimen. The resulting deformations in different directions are measured using linear variable differential transducers (LVDT) attached to both diametral faces of the specimen. The response of the bituminous mixture specimen is captured at three different temperatures of 20, 25, and 30 °C using two different gauge length (half and quarter gauge of the total diameter). A new framework is introduced in this study to evaluate the extent of inhomogeneity and anisotropy of bituminous mixtures. The deformation response of the test specimen captured in the same orientation at different diametral faces is compared to evaluate the extent of inhomogeneity. The extent of anisotropy is evaluated by comparing the deformation response of the test specimen captured at different orientations within the same diametral face. A 15 % variation in the average peak deformation is chosen as the demarcation for determining the extent of inhomogeneity and anisotropy. From this investigation, it is observed that half gauge length experimental data exhibits homogenous and isotropic behavior for all three test temperatures. The quarter gauge length data exhibit similar behavior at 30 °C, whereas it is observed as homogenous and anisotropic at the other two test temperatures.

Nonlinear bending–twisting coupling in electromechanical finite deformation of fiber-reinforced tubular dielectric elastomer for soft actuators

Previous studies have revealed that fiber-reinforced tubular dielectric elastomer actuators (TDEAs) exhibit unique characteristics, such as coupled deformation. Therefore, the present study focuses on the electromechanical behavior of fiber-reinforced TDEAs and analyzes induced coupled bending–twisting deformation analytically and numerically. An analytical framework is derived from the Helmholtz free energy of the system and, using the variation method, leads to equilibrium equations. Despite the limitation of homogeneous deformation, the results indicate relevant facts about the electromechanical behavior and stability of the considered TDEA. On the other hand, a numerical method is devised based on the nonlinear continuum, electro-elasticity, and large deformation theory. The resultant model and presented tangent modulus are validated using experimental data. The model makes it possible to develop a FEM algorithm and explore the behavior of the TDEA under various loading and boundary conditions. For example, the current paper presents the final deformation of a fiber-reinforced TDEA under internal pressure, axial force, and torque. It also explores the bending deformation of a designed tubular bending actuator using numerical analysis and the developed model. Analytical and numerical results share similar trends in longitudinal, radial, and torsional deformations before instability. It is also evident that for voltages higher than the critical voltage, when instability is detected, fiber orientation may cause more significant effects. Analytical and numerical findings confirm coupled deformations in different directions.

Jointless Bioinspired Soft Robotics by Harnessing Micro and Macroporosity.

Although natural continuum structures, such as the boneless elephant trunk, provide inspiration for new versatile grippers, highly deformable, jointless, and multidimensional actuation has still not been achieved. The challenging pivotal requisites are to avoid sudden changes in stiffness, combined with the capability of providing reliable large deformations in different directions. This research addresses these two challenges by harnessing porosity at two levels: material and design. Based on the extraordinary extensibility and compressibility of volumetrically tessellated structures with microporous elastic polymer walls, monolithic soft actuators are fabricated by 3D printing unique polymerizable emulsions. The resulting monolithic pneumatic actuators are printed in a single process and are capable of bidirectional movements with just one actuation source. The proposed approach is demonstrated by two proof-of-concepts: a three-fingered gripper, and the first ever soft continuum actuator that encodes biaxial motion and bidirectional bending. The results open up new design paradigms for continuum soft robots with bioinspired behavior based on reliable and robust multidimensional motions.

Research on the protection of expansive soil slopes under heavy rainfall by anchor-reinforced vegetation systems

An anchor-reinforced vegetation system (ARVS) is a new type of flexible slope protection system. ARVSs are composed of vegetation, anchors and high-performance turf reinforcement mats (HPTRMs) and can maintain the stability of expansive soil slopes while producing superior ecological effects. Through in situ comprehensive monitoring and comparative analyses, we systematically discuss the impact of heavy rainfall on ARVS-protected expansive soil slopes during the local wet season in Nanning. The results show that during the local wet season, the soil temperature and water content in vegetation-covered areas are lower than those in bare areas. The soil temperatures in different areas on the expansive soil slopes decrease with increasing depth. The ARVSs significantly affected the regulation of water transport and soil temperature, which limited soil deformation in different directions. The subsequent heavy rainfall would cause greater deformation of the expansive soil slope when less antecedent rainfall fell. Low-intensity and long-duration heavy rainfall events have greater negative impacts on expansive soil slopes than high-intensity and short-duration rainfall events. Under the action of severe rainfall-evaporation, expansive soil slopes protected by ARVSs can maintain stability.

(Digital Presentation) 4D Printing of Inter-Crosslinking Network Structure Gel with Hinge Structure

4D printing [1] is a new interdisciplinary research area made possible by the merger of scientific developments in additive manufacturing and smart materials [2]. It is a technology that allows 3D printed objects to be deformed over time by applying specific external stimuli [3] and is currently attracting attention as a technology to program biological-like movements into the internal structure of 3D printed objects. In previous research, the movement and deformation of the model has been controlled by devising the shape of the structure, such as a bilayer structure consisting of two materials with different physical properties [4]. However, it is difficult to realize the deformation in different directions simultaneously. The purpose of this research is to develop a 4D printing technology that can simultaneously deform each part of the same object in any direction.To develop a 4D printing technology that can simultaneously deform each part of the same object in any direction, we analyzed the principle of 4D printing by swelling. We measured the swelling rate, swelling speed, compression test, and deformation amount in order to investigate the effects of material and laser irradiation frequency. As a result, it was confirmed that the swelling rate and swelling velocity increased when the amount of the initiator, TPO, was increased from a specific laser irradiation frequency. It was also confirmed that the Young's modulus increased with the increase in the number of laser irradiation. Finally, based on these results, the deformation was measured by varying the amount of initiator and the number of laser irradiations, and it was confirmed that the deformation increased with increasing the amount of initiator and the specific number of irradiations.References Skylar Tibbits, " 4D printing: multi-material shape change", Archit. Des. 84, 116–121 (2014). https://doi.org/10.1002/ad.1710MD Nahin Islam Shiblee, Kumkum Ahmed, Ajit Khosla, Masaru Kawakami, Hidemitsu Furukawa, "3D printing of shape memory hydrogels with tunable mechanical properties." Soft Matter 2018, 14, 7809. https://doi.org/10.1039/C8SM01156GKumkum Ahmed, MD Nahin Islam Shiblee, Ajit Khosla, Larry Nagahara, Thomas Thundat, and Hidemitsu Furukawa. "Recent progresses in 4D printing of gel materials." Journal of The Electrochemical Society 167, no. 3 (2020): 037563. https://doi.org/10.1149/1945-7111/ab6e60MD Nahin Islam Shiblee, Kumkum Ahmed, Masaru Kawakami, Hidemitsu Furukawa, "4D Printing of Shape-Memory Hydrogels for Soft-Robotic Functions." Adv. Mater. Technol. 2019, 4, 1900071. https://doi.org/10.1002/admt.201900071

Structural Analysis and Evolution Model of the Longmaxi Formation in the Yanjin–Junlian Area of the Southern Sichuan Basin, China

The Longmaxi Formation in the southern Sichuan Basin is an important target for shale gas exploration and development. The characteristics and stages of structural development significantly impact shale gas preservation and enrichment. Taking the Longmaxi Formation in the Yanjin–Junlian area of the southern Sichuan Basin as an example and based on the results of surface and underground structural analysis, fluid inclusion tests, apatite fission track experiments, and burial-thermal evolution history analysis, a comprehensive study of the development characteristics and structural stages of the Longmaxi Formation was carried out, and an evolution model was developed. (1) The Longmaxi Formation of the Yanjin–Junlian area has been affected by multistage structural movements and exhibits structural compounding and superposition corresponding to different stages. The formation of surface tracks of the folds and faults has been affected by multidirectional extrusion stresses of the near SN, NE, and near EW. There are three stages of underground faults in the Longmaxi Formation, and the strikes are nearly EW, NE, and nearly SN. (2) Three distribution intervals for the homogenization temperature ranges of fracture fillings are 161–195°C, 121–143°C, and 74–105°C. The apatite thermal history simulation reveals that the Longmaxi Formation experienced three stages of tectonic movement after its formation. (3) There were clearly three stages in the structural development of the Longmaxi Formation in this area: the late Jurassic–Palaeocene (55 ± 5–38 ± 2 Ma), Eocene–early Miocene (38 ± 2–15.5 ± 3.5 Ma), and late Miocene-present (15.5 ± 3.5 Ma–present). Thus, a compound fracture system with superimposed structural deformations in different directions and at different stages formed in the study area. (4) A model for the stages and development of structural tracks in the Longmaxi Formation was established in conjunction with structural analysis and geomechanical theory. The results have guiding significance for the evaluation of shale gas preservation conditions and accumulation in the study area.

Anisotropic structural predictor in glassy materials

There is growing evidence that relaxation in glassy materials, both spontaneous and externally driven, is mediated by localized soft spots. Recent progress made it possible to identify the soft spots inside glassy structures and to quantify their degree of softness. These softness measures, however, are typically scalars, not taking into account the tensorial, anisotropic nature of soft spots, which implies orientation-dependent coupling to external deformation. Here, we derive from first principles the linear response coupling between the local heat capacity of glasses, previously shown to provide a measure of glassy softness, and external deformation in different directions. We first show that this linear response quantity follows an anomalous, fat-tailed distribution related to the universal ω^{4} density of states of quasilocalized, nonphononic excitations in glasses. We then construct a structural predictor as the product of the local heat capacity and its linear response to external deformation, and show that it offers an enhanced predictability of plastic rearrangements under deformation in different directions, compared to the purely scalar predictor.

The Crystallographic Textures and Anisotropy in 2507 Super Duplex Stainless Steel

In this work, the annealing textures in different thickness layers and the Lankford parameter (r‐value) in 2507 duplex stainless steel (DSS) are studied via tensile testing, X‐ray diffraction (XRD), and electron backscatter diffraction (EBSD). The results show that 2507 DSS has poor formability, especially poor deep drawability and noticeable planar anisotropy after cold‐rolling with an average r‐value of 0.86, a planar anisotropy △r of −0.38, and an earring ratio of 7.43. The orientation distribution functions (ODFs) from the different thickness layers show that the texture mainly exists in the ferrite (α) phase, and there is a significant texture gradient in the thickness direction. The texture of the α phase has a strong α‐fiber texture (<110>//RD) and an undeveloped γ‐fiber recrystallization texture (<111>∥ND). The texture intensity of the austenite (γ) phase is weak and is mainly composed of Copper {112}<111>, Brass {110}<112>, Goss {110}<001>, and S {123} <634>. The {001}<110> texture component is highly intense in the α phase and is the dominant reason for the low Lankford parameter (r‐value), whereas the {112}<110> orientation is the main factor for the high planar anisotropy (Δr). The results of the grain orientations after tensile deformation in different directions show that the maximum volume fraction ratios for the {001} and {111} orientations are the root cause of the largest r‐value in the 45° direction.

Applicability of satellite radar imaging to monitor the conditions of levees

Levees are critical systems in safeguarding an area against catastrophic flooding events with potential fatalities and economic losses. Current monitoring methods of levees highly rely on expert judgement, resulting in infrequent and subjective assessments of their status. Satellite radar imaging, in particular using interferometry (InSAR), holds a large potential to monitor the condition of levees with millimetre‐level precision, anywhere on the planet. However, for levee management, the usability of the technique requires significant radar expert knowledge. Here, we provide a comprehensive overview of the state of the art in using time‐series InSAR for systematic levee deformation monitoring. We explore its use to complement existing approaches for assessing levee deformation and failure investigations in a fast, systematic, and cost‐effective way. The applicability of imaging radar satellites is discussed, supported by case studies on levee monitoring in the Netherlands. We elaborate on the technical aspects with respect to levee monitoring using SAR technology, such as estimating deformation in different directions, satellite characteristics, precision, and reliability. We conclude that InSAR is becoming an operational deformation monitoring system, which allows for the detection, tracking, and analysis of irregularities on levee sections with increased efficiency and quality, thus contributing to improved risk management.

Using maximum likelihood to calibrate a six-DOF force/torque sensor

This study presents a new six-DOF force/torque sensor and its calibration method. This calibration method apply the method of so-called maximum likelihood estimation (MLE). MLE is utilized to determine and identify the parameters related to applied torques/forces towards resulted deformations at varied locations of the sensor structure. Formulating such relations in a vector–matrix form, those parameters are captured as coefficients in a matrix related to torques/forces towards angular/linear deformations in different directions. In addition to applying MLE, finite element modeling and analysis are conducted to generate realistic-like empirical data for the afore-mentioned calibration computation. The matrix formed by these coefficients can predict exactly forces and torques by this sensor based on deformations detected by strain gauges. In simulated results the worst sum of error for three forces is less than 0.04% while the worst sum of error for three torques is less than 0.005%. Experiments are also conducted, and the results show that the designed sensor and maximum-likelihood parameter estimation approach achieve favorable performance of predicting forces and torques with error less than 1%. The developed sensor is suitable for real-time sensing of multi-dimensional interactive forces/torques in a robot arm.

Effect of multi-directional forging on the microstructure and mechanical properties of TiBw/TA15 composite with network architecture

In order to optimize the mechanical properties of the as-sintered TiBw/TA15 composite with a network architecture, multi-directional forging was carried out at near β-transus temperatures. The effects of the multi-directional forging on the mechanical behavior of the composite were investigated. The ultimate tensile strength (UTS) and the maximum elongation exhibited a homogeneous distribution in the forged samples, and at ambient temperature, showed increases of 8.4% and 160%, respectively, when compared to those of the as-sintered composite. The microstructures of samples cut from different positions of the forged workpiece were observed by scanning electron microscopy (SEM). The reinforcement retained the three-dimensional (3D) network in the overall workpiece, although the network units suffered deformation in different directions and were slightly flattened. The microstructures of the matrix were composed of a primary α phase (αp) and transformed β phase (βt) consisting of lamellas/needles of a secondary α phase (αs) and residual β phase. The yield stress (YS) of the composite increased with increasing volume fraction of βt and the proportion of low-angle grain boundaries (LAGBs). The above results revealed that the as-forged microstructure did not show any significant variation with orientation, leading to uniform and improved mechanical properties of the composite.

The Statics Characteristic Analysis of Fixed Beam Gantry Machine Tool Crossbeam Based on ANSYS

In order to calculate the crossbeam’s stress and deformation under the weight of gantry machine tool, and analyze whether the deformation meets the precision of design requirements. In this paper, we will use the finite element method to get the stress and deformation in different directions with finite element analysis software-ANSYS. The result shows that the maximum deformation is 14.3 microns which appeared in the middle part of the beam towards the gravity direction and the maximum stress is 4730000 Pa which appeared in the joint of pillar and beam.

Strain direction dependency of martensitic transformation in austenitic stainless steels: The effect of [formula omitted

Uniaxial tensile tests on both a non-textured and a highly textured, fully austenitic stainless steel were performed in both the rolling and the transverse directions. Both materials show mechanically induced phase transformation from the austenitic FCC to the martensitic BCC phase. Differences in overall transformation behavior are observed between the two steels. No direction-dependent transformation behavior is present during deformation of the non-textured steel. However, when a strong texture is present, differences in transformation behavior during deformation in different directions can be observed clearly. The ‘stress induced transformation’ theory, in combination with the austenite texture measured before deformation, is used to explain and model the transformation behavior when straining in different directions. The theoretical results of the stress-induced transformation theory compare well with the measured austenitic textures after deformation and the recorded stress vs martensite fraction curves.

Simulation of yield surfaces for aluminium sheets with rolling and recrystallization textures

The influence of crystallographic texture and homogenization scheme on the yield surface for aluminium sheets has been studied numerically. A rate-dependent single crystal plasticity model was adopted to describe the behaviour of the grains, whereas the behaviour of the polycrystal was obtained either by the crystal plasticity finite element method (CP-FEM) or by the full-constraint Taylor approach. A representative volume element (RVE) of the material including 800 grains was considered. The grain orientations were defined according to typical rolling and recrystallization textures exhibited in rolled aluminium sheets. With CP-FEM, the RVE was discretized with finite elements, using in average 30 cubical solid elements per grain, whereas in the full-constraint Taylor approach, all grains are assumed to be subjected to the same deformation. Stress states located on the yield surface were determined by subjecting the RVE to proportional deformation in different directions, assuming yielding to occur at a given plastic work per unit volume. The yield surface was then described analytically by fitting the Yld2004-18p yield function to the obtained stress states at yield, and further employed to calculate stress ratios and Lankford coefficients in uniaxial tension. The resulting yield surfaces for aluminium with rolling and recrystallization textures are markedly different. The influence of homogenization scheme is moderate, but significant effects are found on the predicted Lankford coefficients.