4 results about "Fracture Toughness Testing" patented technology

This invention discloses a testing device and method for fracture toughness testing of welded joints in pipeline steel under corrosive environments, belonging to the technical field of fracture toughness testing equipment. It includes a test vessel unit and a testing unit. The test vessel unit comprises a test vessel body and a test vessel lid, the lid of which can close onto the opening of the test vessel body. The test vessel lid has an air inlet and an air outlet; the air inlet is used to connect to an air inlet pipe, and the air outlet is used to connect to an air outlet pipe. The testing unit includes a bending clamp assembly and a loading linear displacement measuring assembly. The bending clamp assembly is connected to the shaft of the testing machine and can be used to clamp the test specimen. Driven by the shaft of the testing machine, the bending clamp assembly can press down on the test specimen. The loading linear displacement measuring assembly is connected to a measuring point on the test specimen and is used to measure the linear displacement of the measuring point. This invention enables fracture toughness testing of welded joints under corrosive environments, ensuring the accuracy and safety of the test.

This application belongs to the field of fracture toughness testing under corrosive environments, and specifically discloses a method for calibrating the stress intensity factor loading rate in fracture toughness testing under corrosive environments. The method includes: preparing a specimen and creating a pre-crack; using a corrosive solution to create a pre-corrosive environment at the crack tip; establishing a corrosive environment on a testing machine and performing a three-point bending test on the specimen in the corrosive environment at a preset testing machine loading rate to obtain the specimen's yield strength; loading the specimen in the corrosive environment using multiple different testing machine loading rates to 60%-90% of the yield strength, and recording the force-time curves for each loading; calculating the corresponding stress intensity factor loading rate based on the force-time curves and performing linear fitting to obtain the corresponding functional relationship. This application solves the problem that when conducting fracture toughness testing under corrosive environments, it is impossible to directly set the stress intensity factor loading rate, and existing calibration methods cannot accurately reflect the coupling effect of the corrosive environment.

This invention relates to a method for simulating the uniaxial tensile behavior of a liquid lead-bismuth environment. The method involves conducting uniaxial tensile tests on metallic material specimens in an air environment to obtain stress-strain curves; establishing a two-scale finite element model of the metallic material specimen using ABAQUS finite element software and simulating the uniaxial tension of the two-scale finite element model in the air environment; conducting fracture toughness tests and uniaxial tensile tests on the metallic material in a liquid lead-bismuth environment to obtain stress-strain curves; and simulating the uniaxial tension of the two-scale finite element model in the liquid lead-bismuth environment using ABAQUS finite element software. This invention establishes a finite element model and uses ABAQUS finite element software for calculation, allowing for intuitive observation of the damage behavior of metallic materials during tensile processes in both air and liquid lead-bismuth environments. The established model and parameters can predict different structures and boundary conditions, offering advantages such as accurate results, high efficiency, and low cost. The established two-scale finite element model effectively reduces computational costs.

The present application belongs to the technical field of material fracture mechanics test, and discloses a metal material ductile-brittle transition temperature confirmation method. Based on selected samples and determined test temperature range, impact tests, fracture toughness tests are carried out on the selected samples at different temperatures, and experimental data are recorded. Based on the experimental data of each sample obtained at different temperatures, experimental data points are plotted, and the ductile-brittle transition temperature is obtained based on the experimental data points. The Charpy impact CVN, fracture toughness CTOD / J test data at five different temperatures can be used to calculate the ductile-brittle transition temperature. The present application can obtain accurate ductile-brittle transition temperature value through five effective tests, effectively reducing the test cost and time. Especially for the characteristics of high-strength structural steel ring weld joint toughness dispersion, the present method can quickly and accurately obtain the ductile-brittle transition temperature of high-strength structural steel and ring weld joint DBTT CTOD50 、 DBTT CVN50 and DBTT J50 .