6 results about "Surface strain" patented technology

This invention discloses a method for monitoring the surface deformation evolution process of rock undergoing uniaxial compression creep failure, belonging to the field of geotechnical and rock mechanics testing technology. The steps are as follows: Step 1: Set up a test platform, which includes a speckle spraying system, an imaging and illumination module, a test device, and a host computer; Step 2: Fabricate rock test specimens and arrange the imaging and illumination module; Step 3: Obtain the compressive strength and set the graded loading levels; Step 4: Form a white base layer and black speckles on the surface of the rock specimen, meeting the requirements; Step 5: Conduct a uniaxial graded loading creep test on the rock specimen and acquire image data; Step 6: Process the image data to obtain the strain field evolution process on the specimen surface. This invention uses the above method to record the changes of the white base layer and black speckles during compression using an imaging device, thereby obtaining the deformation creep failure characteristics and evolution law of the rock surface.

The application discloses a kind of directional crystal mould shell automatic detection cleaning system.In the application, by transient air pressure excitation and multi-scale wavelet domain digital speckle correlation detection, the micro crack identification ability is identified from surface opening defect to sub-surface strain anomaly stage, which significantly improves the detection sensitivity of hidden cracks and wall thickness thinning defects, and replaces artificial visual experience determination with full-field strain cloud quantification grading, which significantly reduces the missed detection rate and the quality risk caused by human error. Strain-cleanness dual-factor fusion evaluation simultaneously completes the judgment of structural integrity and internal cavity cleanliness at the same station, improving the completeness and automation of defect evaluation, reducing the drag of batch offline sampling and chemical permeation operation on production rhythm, and eliminating the need for fluorescent penetrant immersion and cleaning process with transient pulse excitation method, which improves the single-piece detection rhythm and reduces the cost of hazardous chemicals procurement, storage and waste liquid treatment.

This utility model discloses an auxiliary tool for installing surface strain gauges, used to align and install the surface strain gauge onto a steel pipe support. The surface strain gauge includes a main body and two mounting ends formed on opposite sides of the main body. The auxiliary tool includes two clamping members, two fixing devices, and two guide positioning strips. The clamping members are used to connect to designated positions on the steel pipe support and provide installation space for the surface strain gauge. The fixing devices are used to fix the surface strain gauge to the mounting surfaces provided by the two clamping members. The guide positioning strips are used to connect the two clamping members so that they maintain the same orientation. This utility model has the advantages of convenient installation and reusability.

This invention discloses a method for testing the transverse crack sensitivity of welded joints through four-point bending loading, relating to the field of welding quality inspection technology. The method includes the following steps: selecting a base material matching the actual welded structure; preparing a welded specimen without pre-existing cracks; creating deformation observation marks in a predetermined area on the surface of the weld and heat-affected zone; simultaneously applying longitudinal four-point bending loads and independent transverse restraint loads to subject the weld and heat-affected zone to multiaxial stress; performing welding operations to generate thermal cycling; dynamically controlling the application sequence and magnitude of at least one load based on real-time temperature signals; simultaneously acquiring temperature field, surface strain, acoustic emission signals, and mechanical load data; calculating initiation and propagation characteristic parameters based on this data to quantitatively evaluate the transverse crack sensitivity of the welded joint. This invention extracts crack characteristic parameters and accurately and quantitatively evaluates the transverse crack sensitivity of welded joints by constructing a multiaxial stress field, dynamically linking welding thermal cycling and load.

The application discloses a kind of asphalt mixture cracking strain threshold determination methods, comprising, preparation multiple asphalt mixture test pieces and carry out fatigue test, collect acoustic emission signal extraction event count, energy count, rise time, peak frequency, amplitude, ringing count and duration seven kinds of indexes;Analysis its time series determines the minimum time data cluster of each kind of index and corresponding threshold;To newly prepared with speckle test piece fatigue test, synchronous collection acoustic emission signal and DIC image;Acoustic emission index normalization, according to cumulative frequency filter out top three indexes, with their first reach threshold time earliest point as damage initiation characteristic moment;Match DIC image at this moment and calculate surface strain field;Crack region of completely cracked state is mapped to the strain field, extract the average value of maximum strain point in the region and be defined as the cracking strain threshold of asphalt mixture;The application provides more reliable quantitative basis for performance evaluation and durability design of asphalt mixture.