Qi Tianzhi

Bio: Qi Tianzhi is an academic researcher. The author has contributed to research in topics: Ultrasonic sensor & Phased array. The author has an hindex of 1, co-authored 4 publications receiving 4 citations.

Ultrasonic phased arrayline scanning sensitivity computing method based on measurement model

Abstract: The invention provides an ultrasonic phased arrayline scanning sensitivity computing method based on a measurement model. The method comprises the steps of processing a synthetic sound field of an ultrasonic phased array as a whole; on the premise of measuring a quasi-plane wave and a small defect body, respectively building a phased array system measuring model and a test block model; calculatingto obtain sound radiation intensity at a cross through hole defect position, solving a frequency domainecho voltage signal of a cross through hole defect, and accomplishing the drawing of a sound field distance-amplitude curve DAC. According to the ultrasonic phased arrayline scanningsensitivity computing method based on the measurement model provided by the invention, the focusing performance and detection sensitivity change rule of an ultrasonic phased array detecting system can be quantitatively analyzed, and different focused sound field distance-amplitude curves are drawn through respectively adjusting the size of the cross through hole defect in the test block model, a phased array focusing depth and a phased array focusing deflection angle.

Ultrasonic rotary scanning and imaging device and method

Abstract: The invention discloses an ultrasonic rotary scanning and imaging device and method. The device achieve a scanning mode of combining rotary motion with linear motion, specifically, ensure high matching between rotary motion and horizontal motion through a special worm-gear and gear set structure. The working state of the ultrasonic rotary scanning and imaging device comprises, a servo motor worksto drive a rotating shaft and a worm-gear to rotate through a synchronous toothed conveyer belt, the worm-gear rotates to drive a screw to rotate, further the rotating shaft and a linear guide rail move relative to each other in the direction of the guide rail, and meanwhile, the rotating shaft moves linearly; during high-speed rotation and linear motion, synchronous ultrasonic signal triggering and collection can be achieved to ensure accurate correspondence of data points and collected positions, thereby facilitating ultrasonic scanning and imaging. The ultrasonic rotary scanning and imagingdevice can be applied to lap joint structure spot welding and laser welding imaging detection.

Phased array double-cavity water boot structure and method for detecting circular and longitudinal cracks of tubes and bars by use of phased array double-cavity water boot structure

Abstract: The invention discloses a phased array double-cavity water boot structure and a method for detecting circular and longitudinal cracks of tubes and bars by use of the phased array double-cavity water boot structure. The phased array double-cavity water boot structure includes a double-cavity water boot and an ultrasonic phased array linear array probe. The upper end face of the double-cavity waterboot is concave to fit the surface of a work piece, and the double-cavity water boot is provided with a water cavity I and a water cavity II; when the circular cracks are detected, the water cavity Iis filled with water, and the water cavity II is not filled with water, and when the longitudinal cracks are detected, the water cavity I is not filled with water, and the water cavity II is filled with water. The phased array double-cavity water boot structure can effectively improve the detection capability, and makes the applicable range of a phased array for detection the tubes and bars wider.The phased array double-cavity water boot structure has good accuracy both in detection of hole defects or crack defects in different directions, and improves the detection efficiency in order to achieve the requirements of rapid online testing.

Triangular matrix focusing imaging workpiece flaw detection method

Abstract: The invention provides a triangular matrix focusing imaging workpiece flaw detection method which comprises the steps of: a line array probe is coupled to a workpiece to-be-tested surface; and detected, a manner that one array element transmits ultrasonic waves and a plurality of array elements receive ultrasonic echoes is used to obtain time sequence Aij(t) of the amplitude value matrix of the ultrasonic echoes, in a data acquisition process, the Aij(t) of j

Method and device for checking ultrasonic water immersion piezoelectric probe

Abstract: The invention discloses a method and device for checking ultrasonic water immersion piezoelectric probe The method comprises the steps of carrying out connection on a pulse generator and an externalresistor, and measuring an input current signal; separating the pulse generator and the external resistor, carrying out connection on the pulse generator and a probe, and measuring an output current signal flowing through the probe; obtaining an acoustic propagation function, acoustic radiation impedance, a resistance value of the external resistor and the resistance value of the pulse generator;and multiplying the output current signal by resistance value sum of the external resistor and the pulse generator to obtain a first product, carrying out multiplication on the input current signal, the acoustic propagation function and the acoustic radiation impedance to obtain a second product, dividing the second product by the first product and then solving a square root, thereby obtaining sensitivity of the probe According to the technical scheme provided by the invention, the sensitivity of the probe can be measured only by measuring the current signal, a test process is simplified, andthe problem that impedance is mismatched in a conventional circuit is solved

Air-coupled ultrasonic interferometry method

Abstract: The invention discloses an air-coupled ultrasonic interferometry method. The method includes the following steps of: taking an air-coupled ultrasonic transducer as a measuring head to face the surfaceof a workpiece, reflecting ultrasonic waves back and forth on the surface of the workpiece, and measuring the phase difference that the first-time reflection echo on the surface of the workpiece reaches the air-coupled ultrasonic transducer; and based on the change of the frequency and wavelength of the ultrasonic waves, converting the measurement of the distance into the change rate of the phaseof acoustic waves relative to the angular frequency of the acoustic waves, wherein the change of the angular frequency of the acoustic waves is equal to the difference between the highest frequency F2 and the lowest frequency F1 in the bandwidth fB of the air-coupled ultrasonic transducer multiplied by 2Pi; and the change of the phase of the acoustic waves is equal to the difference between the integral multiples obtained by dividing the sound path by the wavelength at the frequency F2 and the frequency F1 multiplied by 2Pi. The ultrasonic technology is based on long-term continuous emissionand large-span frequency scanning, and has the advantages of high measurement accuracy and strong anti-interference ability; and the corresponding technology of the ultrasonic technology in laser interference is relatively difficult to achieve.

Clamping device and scanner comprising same

Abstract: The invention discloses a clamping device and a scanner comprising the same. The clamping device comprises: an upper clamping device; a lower clamping device; a motion conversion device which can convert rotary motion and linear motion and comprises a rotary motion part and a linear motion part which are matched with each other; a lock base, wherein the linear motion part is fixedly arranged on the lock base in the first direction, and the lock base comprises a lock cylinder guide part fixedly arranged in the second direction; a lock assembly which is arranged on the lock cylinder guiding partin a sliding mode and comprises a lock first part, wherein the rotary motion part is fixedly connected with the pushing part, the lock assembly is matched with the pushing part, so that the lock assembly moves along the lock cylinder guide part while moving in the first direction along with the lock base under the condition that the pushing part rotates. The clamping device is simple in structure, rapid and efficient.

Plastic pipeline hot melt butt joint ultrasonic phased array detection scanning method

Abstract: The invention relates to the ultrasonic phased array detection technology and aims at providing a plastic pipeline hot melt butt joint ultrasonic phased array detection scanning method. The method comprises the following steps of measuring a width of a single roll rim of a hot melt joint, taking as a scanning length and inputting into a detection host, and then setting a detection parameter on thedetection host; calculating a delay rule of fixed depth interval scanning or fixed angle interval scanning so that focal points are all located on a docking detection plane: calculating a focusing length; calculating a scanning angle and the delay rule; changing a scanning line focal point depth, repeatedly scanning the angle and calculating till that the focal point depth is greater than a scanning end depth, and scanning the delay rule; and detecting defect imaging. In the invention, full coverage of a detection area can be realized and high sensitivity and definition are possessed. In actual detection, a probe is only moved to realize joint detection, and the focusing depth does not need to be adjusted for several times. During a scanning process, parameter setting is convenient, detection efficiency is greatly increased, and detection intelligence and automation can be conveniently realized.