93 results about "In plane strain" patented technology

A method of making a bonded intermediate substrate includes forming a weak interface in a GaN source substrate by implanting ions into an N-terminated surface of the GaN source substrate, bonding the N-terminated surface of the GaN source substrate to a handle substrate, and exfoliating a thin GaN single crystal layer from the source substrate such that the thin GaN exfoliated single crystal layer remains bonded to the handle substrate and a Ga-terminated surface of the thin GaN single crystal layer is exposed. The method further includes depositing a capping layer directly onto the exposed surface of the thin GaN single crystal layer, and annealing the thin GaN single crystal layer in a nitrogen containing atmosphere after depositing the capping layer. The in-plane strain present in the thin GaN single crystal layer after the annealing is reduced relative to an in-plane strain present in said layer prior to the annealing.

The invention discloses a plane strain triaxial apparatus of an axial rolling spacing board. The plane strain triaxial apparatus of the axial rolling spacing board comprises a host part, a loading and measuring mechanism and a collection control mechanism. The host part is structurally characterized in that a base of a pressure chamber is fixedly connected with an axial adjustment piston upward through an axial piston of an axial hydraulic cylinder; the base, a lateral wall and a top cover of the pressure chamber commonly define the pressure chamber; pressure cavities are respectively arranged on the four lateral faces of an inner cavity of the pressure chamber; a sample cap at the axis of the top cover is connected with an axial force sensor upward through a force transmission rod; a contactor of an axial displacement sensor on the force transmission rod is in contact with the upper surface of the top cover; in the inner cavity of the pressure chamber, two hydraulic bags are externally communicated with a pressure source in the loading and measuring mechanism; and sliding restraining mechanisms are respectively arranged in the two pressure cavities along a main middle stress direction in the inner cavity of the pressure chamber. The plane strain triaxial apparatus of the axial rolling spacing board provided by the invention is used for simulating a plane strain stress state.

The invention relates to a visual testing device of high-frequency roadbed vibration under a plane strain condition. The visual testing device comprises a model testing box, a high frequency loading device, a visual vibration monitoring device and an energy dissipation monitoring device, wherein a roadbed model is simulated by arranging multiple layers of bulk materials inside the model testing box; the high frequency loading device is used for simulating a dynamic load generated in the driving process of a high-speed rail train by adjusting the loading amplitude and the frequency, and applying the dynamic load to the roadbed model; the visual vibration monitoring device is connected with the high frequency loading device, comprises a workstation, and a high-speed camera and an adjustable light source which are connected with the workstation respectively, and is used for acquiring image data containing vibration deformation and internal stress wave propagation rules under the action of a high-frequency load; the energy dissipation monitoring device is arranged inside the model testing box, and is used for acquiring fluctuation characteristics inside the roadbed model. Compared with the prior art, the visual testing device has the advantages of multi-point loading, visual monitoring, consistency with a prototype and the like.

A plane strain measuring sensor has the characteristics: at least two bolt holes or locating slot holes are processed in top surface axial direction of multi-direction support, radial hole processed on the same plane with lateral face radial direction is corresponding and interconnected to the bolt holes or locating slot holes of top surface, at least two connecting rods has one end separately set in radial hole of multi-direction support and another end linked separately to the sensors on the same plane but different directions. Tested in laboratory and by bridge load test, the invention is proved to have the advantages: rational design, high sensitivity, easy standardization, small linear error, excellent interference killing and dampness feature, good stability, changeable standardization, wide use, apart from these, after linking to static strainometer or dynamic strainometer, it can measure strain on the same plane but different directions of building unit such as highway bridge and railroad bridge and that of metal unit as well.

The invention discloses a horizontal geotechnical plane stress triaxial apparatus for a pressure chamber structure. The horizontal geotechnical plane stress triaxial apparatus comprises a main machine part, a three-dimensional stress loading and measuring mechanism and a collecting and controlling mechanism. The main machine part structurally comprises four columns fixedly installed on a base, wherein a bottom disc and a top cover are fixedly installed on the upper sections of the four columns, side walls are fixedly connected to four sides of the bottom disc and the top cover, and the bottom disc, the top cover and the four side walls jointly encircle a pressure chamber. A cuboid test sample is placed in the center of an inner cavity of the pressure chamber. The three-dimensional stress loading and measuring mechanism comprises large stress, small stress and intermediate stress loading and measuring mechanisms. According to the device disclosed by the invention, three-dimensional stress, two-dimensional stress and unsaturated three-dimensional stress can be obtained through a plane stress triaxial test, and the stresses do not interfere with each other. Study on shear zones and local deformation of the plane stress test is realized. The mechanical property and strength deformation mechanism of non-saturated soil can be searched under the condition of a plane stress path.

A method for determining equivalent engineering constants in planes of compound materials in the thickness direction includes a first step of determining a three-dimensional stress-strain relation of compound material single layers under a structural overall coordinate system, a second step of determining a two-dimensional stress-strain relation of the compound material single layers in the planes based on the three-dimensional stress-strain relation of the compound material single layers under the structural overall coordinate system according to a plane strain hypothesis in the planes of the compound material single layers in the thickness direction, and a third step of determining the equivalent engineering constants in the planes of the compound material single layers in the thickness direction. The method determines the equivalent engineering constants in the planes of the compound materials in the thickness direction, and the equivalent engineering constants can be directly input into commercial finite element software to endow material properties on each compound material single layer, and the method can be used for building a two-dimensional finite element model of each compound material single layer to solve mechanical response of a compound material structure. The method is favorable for improving analysis precision of the compound material structure and remarkably reducing calculation scales and cost, and has important engineering application value.

The invention discloses a method for analyzing longitudinal vibration of tubular pile on the basis of a radial heterogeneous viscous damping soil model. According to the method, outer soil and inner soil are assumed to be a series of thin layers which are independent from each other, and mutual effects among the soil layers are ignored; a soil body around the pile is portioned into an interior area and an exterior area, the interior area is partitioned into an arbitrary number of circular layers, a soil body unit in each circular layer is a homogeneous and isotropic linear elastic body, a soil body in the exterior extend infinitely along a radial direction, viscous damping is adopted for soil body material damping, and radial displacements of the soil bodies are ignored; on two sides of a pile soil face and every circular layer soil face are continuous in displacements and balanced in stress, and vibration of a pile soil system appears as small deformation; concrete in a pile body is linearly elastic, and stress wave propagation in the pile body meets a plane cross-section assumption; according to basic theories of elastokinetics, longitudinal vibration equations for the soil body around the pile, an inner soil body and the pile body are established; by Laplace conversion, the three equations in the step 5 are solved to obtain a time-domain speed response function of any excitation force at the pile top.

The invention discloses a design method for rock biaxial compression blasting. The method includes the following steps: step S1, obtaining the basic mechanical parameters of rock; step S2, performingtheoretical modeling on the dynamic mechanical response of blast holes during the propagation of cylindrical surface blast waves under a biaxial compression condition; step S3, utilizing a classic Kirsch method to calculate the static stress distribution at the peripheries of the blast holes when the rock is subjected to uniformly distributed horizontal confining pressure Px and vertical confiningpressure Py under plane strain and plane stress conditions; and step S4, adopting a Laplace transform method to solve the dynamic response of the blast holes when the inner walls of the blast holes are subjected to the action of explosion loading under the plane strain condition; Thus, the problems of lack of theoretical basis and guidance of experimental parameter design, large workloads and easy destruction on rock samples by confining pressure loading modes of previous testing methods can be solved.

The invention discloses a method for estimating plane-strain fracture toughness of a metal material, and belongs to the technical field of fracture toughness of metal materials. The method comprises three steps: performing a fracture toughness experiment on a small sample to obtain an experimental value Kq, performing linear fitting on Kq2B and specimen thickness B and performing accurate calculation through straight line slope to obtain KIC. According to the method, the plane-strain fracture toughness of the material can be measured simply and effectively, so that the experiment cost is greatly reduced; in addition, as the KIC of materials (such as amorphous alloys or nano-metal materials) cannot be measured due to a preparation process or relatively high toughness of the materials, accurate parameters can be provided through the method, so that a strong basis is provided for material selection, and particularly, a theoretical basis is provided for the damage tolerance design of a component of the aviation manufacturing industry.

The invention discloses a tester and method for obtaining plane limiting strain of a differential tailor welding blank; the method comprises the following steps: a splint mechanism consisting of an upper clip and a sectional lower clip, a welding blank tensile sample is positioned between the upper clip and the sectional lower clip; a height adjusting sheet is arranged between sectional lower clip and a base, the sectional lower clip and the height adjusting sheet are fixed on the base, a sliding block is arranged between the upper clip and a top pressing plate, the upper clip and the sliding block are fixedly connected by adopting a bolt passing through the middle of the top pressing plate, the tester is arranged in a conventional plate tensile test machine for uniaxial tension test and the limiting strain value is measured; the tester and method of the invention can obtain better plane strain state, have stable test result, simple structure, low test cost, simple and convenient operation, and high test efficiency and the sample is flat after the test.

The invention discloses a device for performing an ultimate drawing test of an anchor plate under a plane strain condition. The device is characterized by comprising a test soil box, a main support, asoil baffle, an anchor rod, a displacement device and a loading device; the test soil box is filled with a soil body; one side of the test soil box is transparent, so that the observation can be facilitated; a non-transparent side wall of the test soil box is punched for the anchor rod to penetrate through; the soil baffle is arranged in the soil box, and can be moved to realize test devices forthe front fracture surface and the ultimate bearing capacity of the anchor plate; the end part of the main support is connected with the displacement device; and the displacement device is connected with the loading device. The invention provides a test model device which can be used for researching the ultimate bearing capacity of the anchor plate in the ultimate drawing test by accurately controlling different angles under the plane strain condition, and the development law of the front soil body fracture surface of the anchor plate.

The invention discloses a method for testing the cracking toughness of materials by an orthogonal cutting process. The method comprises the steps of: 1) pre-processing a material sample to be measured; 2) mounting a force measuring instrument below a workpiece and fixedly connecting the force measuring instrument with a working table of a machine tool for measuring a cutting force Fc and a cutting thrust force Ft obtained by the force measuring instrument; 3) cutting the sample to be measured on the machine tool; 4) calculating or measuring the chip thickness ach under different cutting thicknesses ac; and 5) calculating to obtain the cracking toughness Gc of the cut material. The method has the beneficial effects that the stress state of the material in the orthogonal cutting process is a plane strain state, the sample to be measured does not need to be made into a specific shape, and the test process is simple and easy to implement; and a no-layer material and a basic body can be quickly cracked by a cutting tool, the problem of crack blunting of a high-toughness and low-yield-strength material can be effectively solved, and the conventional test method can be completely replaced with the method for measuring the cracking toughness of the material by the orthogonal cutting process.

The invention disclose a method for predicating high-strength steel fatigue crack growth performance, and belongs to the technical field of metal material fatigue crack growth. The method comprises the following three steps: testing the tensile strength deltab by tensile test, performing plane strain fracture toughness test to obtain the fracture toughness KIC of the material, and substituting thetwo sets of data into a high-strength steel fatigue crack growth formula, so as to obtain the fatigue crack growth performance of the material. According to the invention, the fatigue crack growth performance can be predicated by simply utilizing the static mechanical performance of the material, and therefore, not only is the defect that the physical significance of parameters in the fatigue crack growth Paris formula is indefinite solved, but also time and expenses for fatigue test are saved. Meanwhile, the method provides a reference standard for material selection of engineering components, and opens up a new thought for how to optimize the fatigue crack growth performance of the material.

Piezoelectric actuators for synthetic jets and other devices are disclosed having orthotropic piezoelectric bimorphs with increased out-of-plane displacements for greater responsiveness to applied electric fields. In some embodiments, the piezoelectric actuators may include interdigitated electrodes applied to a surface of a piezoelectric plate to produce greater in-plane strains in the plate and greater out-of-plane displacements of a flexible diaphragm of the synthetic jet. In other embodiments, the actuator includes an orthotropic piezoceramic plate having a greater d coupling coefficient in one in-plane direction and in the other in-plane direction to cause desired diaphragm out-of-plane displacements when an electric field is applied by electrodes.

The invention discloses a measuring and testing device and a measuring and testing method for a soil mass displacement field around a loaded structure. The measuring and testing device and the measuring and testing method solve the problem of discontinuous displacement application in the prior art, and have the beneficial effects that the measurement precision is high and the model can realize repeated use. The measuring and testing device is characterized in that: the measuring and testing device for the soil mass displacement field around the loaded structure comprises a bracket, a plane strain model tank, a loading mechanism and a recording mechanism, wherein the plane strain model tank supported by means of the bracket, at least one side surface of the plane strain model tank is transparent, the plane strain model tank is filled with a filler, structures are embedded inside the filler, the structures are connected with one end of a connecting rod; the loading mechanism is supportedby means of the bracket, the loading mechanism comprises a lifting component capable of realizing up and down lifting motion, a stress sensor is arranged between the lifting component and the other end of the connecting rod, and a displacement sensor is supported by means of the fixed bracket; and the recording mechanism is arranged on at least one side of the plane strain model tank for recording the displacement changes of the filler in the plane strain model tank.

The invention discloses a method for manufacturing and testing ideal cracks of a metal material. The manufacturing method comprises the following steps: processing the metal material into a flat plate; prefabricating notch cracks in the flat plate; placing pressure transmission pieces on the two surfaces of the flat plate to form a sandwich structure, wherein a contact range of the pressure transmission pieces and the flat plate covers the notch cracks; and heating and pressurizing the sandwich structure so that a thickness of the range of the notch cracks on the flat plate is reduced, and notch crack surfaces are folded again to form an ideal crack surface similar to fatigue cracks. Prefabricating of the ideal cracks is achieved through a thermoplastic forming characteristic of the metalmaterial, an effective technical basis is provided for measurement of the amorphous alloy plane strain fracture toughness, the measurement of the small sample material plane strain fracture toughnessis facilitated, deformation in an ideal crack tip expansion process is conveniently monitored, a process is simple, and cost is low.

A micromechanical device capable of providing out-of-plane motion and force generation in response to an in-plane strain applied to the device is provided. Embodiments of the present invention comprise one or more islands that are operatively coupled with one or more hinges. The hinges are operative for inducing rotation of the islands when a lateral strain is applied to the structure. In some embodiments, the hinges are also electrically conductive such that they enable electrical communication between the one or more islands and devices external to the structure. Some embodiments of the present invention are particularly well suited for use in biological applications. Some devices in accordance with the present invention are fabricated using conventional planar processes, such as flex-circuit fabrication techniques.