8 results about "Bulge test" patented technology

The invention relates to the technical field of mechanical property testing of metal materials, and provides an unsteady-state in-situ high-temperature forming property testing device and method. A punch constant strain rate loading model is arranged in the device, the punch moving speed is adjusted in real time to realize punch constant strain rate loading, and the rheological behavior of a constant strain rate sensitive material in a complex stress state is accurately tested; a rapid cooling system is arranged, so that accurate simulation of complex unsteady-state forming processes such as actual hot stamping and warm forming is realized, and the unsteady-state in-situ high-temperature forming performance of the material is obtained; in combination with a DIC dynamic strain measurement technology, a strain field and deformation force are collected in real time in a plate high-temperature plane stress bulging test, and local necking strain and main strain and secondary strain change paths are determined. According to the method, the reliability of researching macroscopic rheological behaviors such as strain field distribution, flow behavior, hardening mechanism, forming limit and fracture limit of the plate in a complex stress state can be remarkably improved.

The application discloses a kind of hydraulic bulging test piece forming quality control method, comprising the following steps: setting the bulging information and initial bulging information of standard test piece;Utilize the bulging information of standard test piece and the initial bulging information, based on mold, obtain the bulging test piece of standard morphology, the mold is the composite mold of toughened glass and diamond;Based on the mold, the bulging test piece of standard morphology is detected, and based on the bulging information of standard test piece, the control of hydraulic bulging test piece forming quality is realized.The application determines the bulging distance by calculating the light propagation time in air, the toughened glass propagation time and the diamond propagation time, and obtains the bulging height and axial feed amount in this way, which can observe the bulging height of the test piece in real time, master the bulging condition, so as to realize quality control.

The application discloses a kind of based on free bulging thin-walled pipe flow stress measurement method, including establishing database, writing depth learning algorithm, bulging test;The database is established by using ABAQUS finite element software to establish thin-walled pipe free bulging model, different flow stress curves are constructed based on Swift flow stress mathematical model and input into model, gather pipe material bulging height curve, and establish the database of corresponding relationship;The depth learning algorithm is written by using Python programming language as model algorithm platform, and the neural network structure is established, the data is forwardly transmitted and the reverse transmission is carried out by using error back propagation method, and the depth learning algorithm is gradually improved by continuously learning data;The bulging test is carried out by bulging test to pipe material, and the flow stress of pipe material is obtained by using depth learning algorithm;The application can improve the simplicity of pipe material flow stress measurement method.

The present invention relates to a method for testing the properties of thin metal plates, and proposes a double-elliptical die bulging test method for thin metal plates. The experimental apparatus employed primarily comprises a double-elliptical die, a sealed pressure plate, a CCD camera, a control system, a pressure medium output system, and a temperature regulation system. The asymmetry of the double-elliptical die allows for different boundary conditions and loading conditions to be established at different locations on the plate surface, resulting in different stress ratios at various points within the plate surface during bulging. By monitoring the stress, strain, and dimensional parameters of each point with different stress ratios during the bulging deformation process, a single bulging test can obtain sufficient plate performance parameters under a sufficient range of stress states and deformation degrees. Compared to bulging tests using circular or elliptical dies, the double-elliptical die bulging test significantly reduces the number of tests, lowers testing costs, shortens the testing cycle, and improves experimental efficiency.

The present invention belongs to the field of performance testing of metal sheets under complex non-linear loading conditions, and provides a bulging test device and method for metal sheets that can achieve continuous rotation of the stress principal axis. By changing the aspect ratio value of the ellipse of the upper die cross-section of the rotating female die and the directions of the major and minor axes, the present invention changes the constraint boundary conditions received by the poles of the metal sheet during the bulging process, thereby realizing the changes in the in-plane principal and secondary stress directions and magnitudes at the poles of the metal sheet during bulging. Through the device and method of the present invention, an accurate constitutive model of the metal sheet can be established under conditions closer to the actual forming process; the rotation path of the stress principal axis direction, the change path of the magnitude, and the initial angle between the metal sheet material direction and the stress principal axis direction can all be adjusted according to actual requirements.

The invention relates to the technical field of test simulation, in particular to a method for simulating and predicting a high-temperature forming limit curve of a medium-thickness plate material. The method comprises the following steps: constructing a plate model and a mold model for a bulging test; grid division processing is conducted on the plate model and the mold model; defining a property model and a thermal material model of the plate model and the mold model; wherein the property model comprises a plurality of groups of property parameters, and the thermal material model comprises a plurality of groups of thermal parameters; defining a friction coefficient, an ambient temperature, an initial temperature and a heat conductivity coefficient between the model and the mold model; the necking instability of the material in the thickness direction is recognized through the maximum male die force criterion and the strain path transformation criterion; and representing the temperature field change, the pressing displacement change and the thinning rate change of the plate material model, and carrying out simulation prediction on the high-temperature forming limit curve of the medium-thickness plate material. According to the scheme provided by the invention, the medium-thickness plate material high-temperature forming limit curve can be obtained through simulation prediction.

The invention provides a method and device for determining the crack propagation capacity of a plate and electronic equipment, and relates to the field of plate performance detection, in particular to the method and device for determining the crack propagation capacity of the plate, in the process of performing a bulging experiment on the target plate, a load displacement curve of the target plate is obtained; intercepting a line segment between the highest point of the load displacement curve and the end point of the load displacement curve as a target line segment; according to the slope value of the target line segment, the crack propagation resistance index of the target board is determined, and the crack propagation resistance index represents the edge cracking resistance of a board product from the target board.

An embodiment of the present application provides a method for analyzing tensile strain mark defects, comprising: obtaining the yield plateau length of a high-strength steel to be tested; performing a bulging test on the high-strength steel to be tested to obtain a part to be tested that exhibits tensile strain marks; performing a strain analysis on the part to be tested to determine a first strain value when the tensile strain mark appears on the part to be tested, and a second strain value when the tensile strain mark disappears on the part to be tested; and determining a strain analysis table for the high-strength steel to be tested based on the yield plateau length, the first strain value, and the second strain value. The technical solution of the embodiment of the present application can, to a certain extent, clarify the correspondence between the yield plateau and the strain amount when the tensile strain mark defect occurs, thereby taking corresponding measures based on the strain amount or the yield plateau length.