918 results about "Strain rate" patented technology

Systems and methods for noninvasive assessment of cardiac tissue properties and cardiac parameters using ultrasound techniques are disclosed. Determinations of myocardial tissue stiffness, tension, strain, strain rate, and the like, may be used to assess myocardial contractility, myocardial ischemia and infarction, ventricular filling and atrial pressures, and diastolic functions. Non-invasive systems in which acoustic techniques, such as ultrasound, are employed to acquire data relating to intrinsic tissue displacements are disclosed. Non-invasive systems in which ultrasound techniques are used to acoustically stimulate or palpate target cardiac tissue, or induce a response at a cardiac tissue site that relates to cardiac tissue properties and/or cardiac parameters are also disclosed.

The invention relates to a system and a method for performing impact loading on a micro test piece and measuring dynamic mechanical property. The method comprises the following steps of: instantly accelerating a bullet by using an electromagnetic pulse launch technology and launching the bullet at high speed; transmitting a stretching stress wave generated by collision of the bullet to the micro test piece by using a separated Hopkinson bar technology so as to generate the impact loading on the micro test piece; recording strain data of an input bar and an output bar, and acquiring an enlarged surface dynamic deformation image of the micro test piece; analyzing and obtaining a stress strain curve of the micro test piece subjected to the impact loading having different strain rates; and analyzing the surface dynamic deformation image of the micro test piece and obtaining a distribution of a bidimensional displacement field and a strain field during dynamic impact loading of the micro test piece. By the system and the method, the problem of research on the dynamic mechanical property of a micro electro mechanical system (MEMS), and membrane materials such as piezoelectric thin films, ferroelectric thin films and the like is solved.

The invention relates to a method for predicting the dynamic mechanical property of a material based on a BP artificial neural network, aims at achieving the prediction of the dynamic mechanical property of the material through the BP artificial neural network, and belongs to the testing field of the dynamic mechanical property of the material. The principle of the method comprises the steps: collecting stress-strain data through employing a high-speed tensile test method, and obtaining a training sample set after normalization preprocessing; building a BP artificial neural network model through designing an input layer, a hidden layer and an output layer, and selecting a proper transfer function, a training function, and a learning function; carrying out the iterative training of the BP artificial neural network through employing the training sample set, and obtaining an optimal prediction network. The above prediction method can be used for the prediction of the dynamic mechanical property of the material, can achieve the quick prediction of a flow curve of the material at different strain rates in a short time, and can provide enough sample data for automobile safety simulation.

Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.

The invention provides a stretching and compression stress wave generator based on electromagnetic force and an experimental method. The stress wave generator is such structured that a capacitor charger is connected with a loading gun. A main coil, an insulating layer and a secondary coil all sleeve the locating shaft of a tapered amplifier. A power supply system is employed to provide the main coil of the loading gun with instant strong current, so strong eletromagnetic repulsion is generated between the main coil and the secondary coil; and the eletromagnetic repulsion is converted into stress waves which are amplified by the tapered amplifier and then output to a Hopkinson bar. The stretching and compression stress wave generator has a simple structure and strong controllability, can realize a strain rate and a strain scope which cannot be reached by a traditional disconnect-type Hopkinson bar, allows Hopkinson bar experimental techniques to be standardized, realizes integration of experimental apparatuses of a pull bar and a pressure bar and reduces complexity and occupied space of equipment.

The invention relates to a six-dimensional force sensor which comprises a sensor elastomer and resistance strain gages, wherein the sensor elastomer comprises a cylindrical shell and a crossed elasticbeam; the crossed elastic beam is positioned in the center in the shell and comprises a strain beam (1) and a loading platform (3); an upper base (6) and a lower base (10) are respectively positionedat both ends of the shell; force transmission columns (7) are positioned in the middle of the shell and connected with an upper elastic beam (4) and a lower elastic beam (8); a flexible beam (2) is positioned between the force transmission columns, and the inner side of the flexible beam (2) is connected with the strain beam. A sensor force sensing element comprises the upper elastic beam, the lower elastic beam and the strain beam, and 28 resistance strain gages are attached to the proper position on the force sensing element, wherein 24 strain gages form six groups of full-bridge detectingcircuits for realizing the acquisition of six-dimensional force information, and other four strain gages are reserved. The invention has the characteristics of compact structure, large rigidity, lessdimensional coupling, high precision and good dynamic performance and can be used for the research of an intelligent robot, automated detection and control, bionic motion analysis and sports research.

Methods and systems for measuring mechanical property of a vascular wall and a method and system for determining health of a vascular structure are provided wherein local deformation of a vessel wall resulting from physiologic pressures with altered transmural forces is measured. A non-invasive free-hand ultrasound scanning-procedure was performed to apply external force, comparable to the force generated in measuring a subject's blood pressure, to achieve higher strains by equalizing the internal arterial baseline pressure. When the applied pressure matched the internal baseline diastolic pressure, strain and strain rate increased by a factor of 10 over a cardiac cycle. Radial arterial strain was assessed in the vessel wall over the entire deformation procedure using a phase-sensitive, two-dimensional speckle-tracking algorithm. An elastic modulus reconstruction procedure was developed to estimate the non-linear elastic properties of the vascular wall.

The invention discloses a production method of low-alloy complex-phase (Q and P) steel. In the method, low-carbon manganese silicon steel or low-carbon manganese silicon aluminium steel is used as raw materials, and the method comprises the following steps of: heating a steel blank to 1100-1250 DEG C; keeping the temperature for 5-120 minutes, and then cooling to 1000-1100 DEG C at the speed of 5-20 DEG C/s; then roughly rolling at the strain rate of 1-50 s<-1>; then cooling to a temperature ranging from T1 to T2 at the speed of 5-50 DEG C/s, wherein T1=A3-(A3-30) DEG C, and T2=Ar3-(Ar3+10) DEG C; then finely rolling at the strain rate of 1-50 s<-1>; after the fine rolling, cooling to the temperature ranging from T3 to T4 at the speed of 40-100 DEG C/s, wherein T3 is lower than a Ms point, and T4 is higher than a Mf point; then heating to 250-450 DEG C; keeping the temperature unchanged for 3-30 minutes, and then cooling to room temperature. Experiences prove that the low-alloy complex-phase (Q and P) steel produced by using the method has higher strength, good plasticity and comprehensive mechanical property better than that of the conventional complex-phase (Q and P) steel.

A microcomputer-controlled electro-hydraulic servo rock tri-axial dynamic shear-seepage coupling multifunctional test method belongs to the technical fields of rock mechanics and engineering technology and is characterized in that a test apparatus is composed of a loading system, a sealing system, a multiphase fluid injection system, an acoustic emission monitoring system, a deformation monitoringsystem and a data collection system. The test method not only solves technical problems that a tri-axial pressure chamber cannot be used for performing large displacement shear-seepage coupling of rocks under high confining pressure and high seepage pressure, and also can achieve various extended functions on the basis of the technology. The apparatus can achieve servo control loading of force, displacement and strain rate in shear direction and injection seepage of a multiphase fluid during dynamic shear. In addition, the apparatus is equipped with a temperature control system for performingconstant temperature control to the tri-axial pressure chamber at 0-200 DEG C; therefore, a series of extended experiments of dynamic shear-seepage coupling features of rocks under effect of temperature can be carried out.

This invention relates to a foamable blend comprising an in-reactor polymer blend comprising: (a) a first propylene polymer component comprising 90 to 100 wt % propylene and from 0 to less than 10 wt % comonomer, said first propylene component having a Tm of 120° C. or more; and (b) a second propylene polymer component comprising from 30 to 90 wt % propylene and 70 to 10 wt % comonomer, said second propylene polymer having an Mw of 30,000 g/mol or more, and said second propylene-containing polymer having a crystallinity different by at least 5% from the first polymer, wherein the polymer blend, prior to combination with a foaming agent, has: (i) a Tm of at least 120° C.; (ii) a MFR of 10 dg/min or more; (iii) a tensile strength of at least 8 MPa; (iv) an elongation at break of at least 200%, and (v) a ratio of elongational viscosity at break to linear viscosity of 5 or more when the elongational viscosity is measured at a strain rate of 1 sec⁻¹ and temperature of 180° C.; and where when the blend is foamed with a foaming agent, the foamed article has a density of 800 kg/m³ or less.

An ultrasound machine is disclosed that displays a color representation of moving structure, such as a cardiac wall tissue, within a region of interest on a monitor. The color representation is generated by displaying at least one color characteristic corresponding to a movement parameter of the structure, such as velocity or strain rate. The movement parameter is mapped to the color characteristic by apparatus comprising a front-end that generates received signals in response to ultrasound waves. A Doppler processor generates a set of parameter signals representing values of the movement parameter within the structure. A control processor adaptively generates a mapping function based on the distribution of the parameter signals to map the parameter signals to a set of color characteristic signals. A display processor applies the mapped values of the color characteristic legend to the values of the movement parameter representing the moving structure, to display a color representation on the monitor in response to the mapping function.

The invention relates to a hot galvanizing sedan plate and the production method thereof, which solves the following problems: P and S in steel are difficult to control because of being lowly required; as to a horizontal Sendzimir hot galvanizing machine, the recrystallization temperature of a steel plate is slightly high, and the plastic strain ratio and extension are low. The high-plastic-strain-ratio galvanizing plate is composed of no more than 0.004% by weight of C, no more than 0.020% by weight of Si, 0.05% to 0.20% by weight of Mn, no more than 0.016% by weight of 0.016, no more than 0.015% by weight of S, 0.04% to 0.07% by weight of Ti, 0.02% to 0.06% by weight of Als, no more than 0.003% by weight of N, and the balance Fe and unavoidable impurity. The production steps are as follows: smelting by hot metal desulphurization and secondary refining process; hot rolling; cold rolling with a total reduction of 80%; and galvanizing. The invention has the characteristics that the method is pure Ti processing; the control scopes of S and P are wide; the plastic strain ratio is r90 DEG C >=2.5, the extension A80mm is 45% to 50%; and the current process route and equipment is unchanged.

A method of forming a component from a gamma prime precipitation-strengthened nickel-base superalloy. The method entails formulating the superalloy to have a sufficiently high carbon content and forging the superalloy at sufficiently high local strain rates so that, following a supersolvus heat treatment, the component is characterized by a fine and substantially uniform grain size distribution, preferably finer than ASTM 7 and more preferably in a range of about ASTM 8 to 10.

The invention discloses an electromagnetic induction type Hopkinson torsion and pressure bar loading device and an experimental method. An anode output line of a capacitance charger is connected with an anode line of a loading gun while a cathode output line of the capacitance charger is connected with a cathode line of the loading gun, and consequently both compressive stress waves and tensile stress waves can be generated, and application to loading of Hopkinson torsion and pressure bars is realized. Loading systems of the Hopkinson torsion and pressure bars can be arranged on the same device, the strain rate and the strain range which are beyond the reach of traditional split Hopkinson torsion and pressure bar experiments are realized to further realize technical standardization of the Hopkinson torsion and pressure bar experiments, integration of torsion and pressure bar experiment devices is realized, and accordingly equipment complexity and space occupancy are reduced.

Shock-absorbing, load-cushioning interface structure for use inside, and in operative cooperation with, the shell of a helmet for operative interposition such a shell and the head of a wearer. This structure is characterized with features and performances including (a) compression-deformation-and-slow-return viscoelasticity, (b) non-springy (anti-rebound) during a return from deformation, (c) acceleration-rate(strain-rate)-sensitivity, and (d) a durometer associated with an ILD number which is no less than about 15-ILD.

The invention discloses a device and a method for testing looseness of rock under disturbance of a strain rate in the loading process of a pendulum bob. The device is suitable for testing the loosing performance of a rock test piece under the compression effect of axial static load (and confining pressure), a transmission bar on an axial pressure loading plate is driven by utilizing a worm and gear and adjusting a hand-operated rocking handle, and the loose test of the transmission bar on the test piece under the grading displacement loading and constant displacement condition can be realized; a stable axial static load (and confining pressure) can be applied by the device to the rock sample, and then the load is impacted by adjusting the pendulum bob so as to apply the axial power, so that the rock sample is broken, and the mechanical property of the rock after suffering the impact load at a long-term loosing state can be tested. By adopting the device and method, the mechanical response characteristics and damage mechanism of the rock under the long-term loosing effect and instantaneous dynamic disturbance effect can be studied, and an important theoretical significance on evaluating the stability of an underground digging space and designing a permanent support of an underground rock project can be realized.

The invention provides a device and a process for the hot pressing and molding of an amorphous alloy. The device is provided with a vacuum, inert gas or nitrogen gas protective environment, and a mould set and an induction heating coil positioned in the environment; the mould set comprises an upper mould, a lower mould and a molding mould; the induction heating coil is at least wound in a peripheral space of the molding mould and is not contacted with the molding mould; and the process sequentially comprises the following steps in the vacuum, inert gas or nitrogen gas protective environment: blank placement, induction heating, hot pressing and molding, cooling, and mould extraction. By adopting an induction heating mode, the process can rapidly concentrate on heating a molded blank to Tg temperature above, and carry out the hot pressing and molding within the temperature range between Tg and Tm or the Tm temperature above; a molding strain rate can reach between 10 and 10S; and the process has high processing efficiency and can effectively prevent crystallization of the amorphous alloy in the molding process within shorter temperature rise time.

The invention relates to an in-situ high-frequency fatigue material mechanical test platform under a scanning electron microscope based on a stretching/compressing mode and belongs to the field of machinery and electronics. The test platform comprises a precise loading unit, a precise motion conversion unit, a load/displacement signal acquisition and control unit, a high-frequency driving unit and a test piece clamping and connecting unit. The test platform provided by the invention has the advantages that the structure is compact, the test precision is high, the strain rate and the test frequency are controllable, an in-situ high-frequency test based on the stretching/compressing mode can be performed on a three-dimensional test piece aiming at centimeter-scale or above in characteristicdimension under the condition of observation of various imaging instruments, the on-line monitoring can be carried out on the microcosmic deformation, damage and breaking process of a material under a fatigue stress, and a novel test method for revealing microcosmic deformation behaviors and a damage system of the material is provided.

This invention presents an innovative framework for the application of machine learning for identification of alloys or composites with desired properties of interest. For each output property of interest, we identify the corresponding driving (input) factors. These input factors may include the material composition, heat treatment, process, microstructure, temperature, strain rate, environment or testing mode. Our framework assumes selection of optimization technique suitable for the application at hand and data available, starting with simple linear, or quadratic, regression analysis. We present a physics-based model for predicting the ultimate tensile strength, a model that accounts for physical dependencies, and factors in the underlying physics as a priori information. In case an artificial neural network is deemed suitable, we suggest employing custom kernel functions consistent with the underlying physics, for the purpose of attaining tighter coupling, better prediction, and extracting the most out of the—usually limited—input data available.