Beijing Institute of Technology

Yuren Lu

Chunguang Xu

Peng Yin

Shuangyi Li

Wenyuan Song

Dezhi Li

Peilu Li

Ruili Jia

Jianfeng Song

Zhaowei Miao

Zhixiang Li

A device for controlling deformation of a large-scale crankshaft comprising a crankshaft holder that is arranged for fixing the crankshaft so that the crankshaft is aligned with an axis; a regulatory bracket that is arranged on the crankshaft holder at a position corresponding to the crankshaft; and a high-energy acoustic beam transducer that is arranged on the bracket and is provided with an end part coupled with the crankshaft. The crankshaft is fixed through the crankshaft holder, high-energy ultrasonic waves are injected into the crankshaft by the transducer, mass points in the crankshaft are driven to vibrate along the acoustic beam direction, and machining residual stress of the crankshaft is removed through the high-energy acoustic beam to realize the regulation and control of the residual stress in the material in the specific direction, so that machining precision of the crankshaft is ensured and machining deformation of the crankshaft is reduced.

Device for controlling deformation of a large-scale crankshaft

A control device for reducing and homogenizing welding residual stress by acoustic waves, comprising: a fixing tool having two rows of through holes; a plurality of ultrasonic transducers each having a body and a conical horn transmitting portion at a lower end of the body, wherein lower ends of the horn transmitting portions are fixedly connected with flanges, the horn transmitting portions of the ultrasonic transducers extend into respective through holes of the fixing tool to be in contact with welded parts below the fixing tool, the flanges are fixed to the fixing tool by bolts, and the two rows of through holes are arranged both sides of a welding seam of the welded parts; and a driving device for driving the ultrasonic transducers to operate. A corresponding control method is also provided. The control device can be used to control residual stress at the welding seam of steels.

Control device and control method for reducing and homogenizing welding residual stress by acoustic wave

A device and a method for ultrasonic detecting a mechanical member based on magnetic fluid coupling. The device comprises a magnetic field generating apparatus, magnetic fluid and an ultrasonic probe. The magnetic field generating apparatus has a cylindrical structure, into which the magnetic fluid is injected, where an upper portion of the apparatus is provided with the ultrasonic probe a front end that vertically extends into a liquid level of the magnetic fluid, and a bottom portion of the apparatus covers a detected position of a member under detection. The magnetic fluid at least contains magnetic suspension particles and oil-based or water-based liquid. With the device and the method, the ultrasonic probe is coupled with the member under detection to realize ultrasonic detecting of the service stress of the member under detection.

Device and method for ultrasonic detecting of mechanical member based on magnetic fluid coupling

A device for reducing and homogenizing residual stress of a metal frame including a substrate, a frame fixing device and ultrasonic vibrators. A groove with an upward opening is provided in the middle of the substrate, and a shape enclosed by vertical side walls of the groove matches a shape of an outer frame of a metal frame to be processed. A plurality of through holes that are horizontally diverged are arranged around the side walls of the groove, and the through holes are vertically intersected with the groove. The ultrasonic vibrators are provided on the substrate and front ends of the ultrasonic vibrators extend into respective through holes to abut against the metal frame in the groove. The frame fixing device is also arranged in the groove where the metal frame is located, after the metal frame to be processed is placed in the groove.

Device for reducing and homogenizing residual stress of a metal frame

The present disclosure is related to the technical field of propellant performance research, and in particular, to a method for reducing propellant curing residual stress by a high-energy acoustic beam. The method includes the following steps: injecting a propellant slurry into a curing container and waiting for the propellant slurry to start curing; actuating, when the propellant slurry starts curing, a high-energy acoustic beam generator and a high-energy acoustic beam transducer to continuously emit high-energy acoustic beam to the propellant slurry in the curing container until the propellant slurry is cured to form a propellant grain; and closing the high-energy acoustic beam generator and the high-energy acoustic beam transducer. The method for reducing propellant curing residual stress by high-energy acoustic beam provided in the present disclosure can reduce residual stress inside the propellant in an effective manner, thereby ensuring operation safety of the aerospace equipment.

Method for reducing propellant curing residual stress by high-energy acoustic beam

A method for controlling deformation of a large-scale crankshaft comprising detecting and recording stress value(s) of part(s) to be regulated by the crankshaft; fixing the crankshaft on a tool to couple transmitting ends of high-energy acoustic beam transducers with the part(s) to be regulated; turning on the high-energy acoustic beam transducers to emit high-energy acoustic beams into the crankshaft, controlling working frequencies of the high-energy acoustic beam transducers within a range of 10-30 kHz, and setting a predicted regulation and control time according to the stress value(s) of the part(s) to be regulated; and closing the high-energy acoustic beam transducers when the predicted regulation and control time is reached, and taking the crankshaft out of the tool.

Method for controlling deformation of a large-scale crankshaft

The present application relates to the technical field of the research on energetic composite materials, and in particular to a device and a method for controlling transverse and longitudinal stress waves during the curing process of energetic composite materials. The device for controlling transverse and longitudinal stress waves comprises a curing vessel containing an energetic composite materials to be cured; a vertical exciter that is vertically incident to the curing vessel; and a plurality of oblique exciters which are arranged around the vertical exciter and obliquely incident to the curing vessel, wherein the oblique exciters have inclination angles between a first critical angle and a second critical angle. By means of incident transverse and longitudinal waves, the internal radial residual stress and the internal axial residual stress are reduced and homogenized, so as to improve stability and mechanical property of the energetic composite materials during curing.

Device and method for controlling transverse and longitudinal stress waves during curing process of energetic composite materials

The present disclosure relates to a method for reducing and homogenizing residual stress of a component, which comprises: detecting stress value(s) of regulation portion(s) of the component; placing the component in a container containing a fluid medium so as to immerse the component in the fluid medium; emitting, by an acoustic wave generator, an elastic wave to the fluid medium in a manner of emitting towards the regulation portion(s) of the component, and determining an emitting period of time and a frequency of the elastic wave based on the stress value(s); returning to the step Swhen the emitting period of time has elapsed, until the stress value(s) is stable. The method and the device solve the problems that it is difficult to reduce and homogenize the residual stress on high-precision machined components, complex structural components, thin-walled structural components, and low-stiffness components.

Method and device for reducing and homogenizing residual stress of a component

A device and a method for ultrasonic detecting a rotating member based on magnetic fluid coupling, wherein the device comprises an ultrasonic probe, magnetic field protection rings, magnetic fluid and a magnetic fluid protection cover. The ultrasonic probe is arranged above the rotating member that is horizontally placed. Front ends of a transmitting ultrasonic transducer and a receiving ultrasonic transducer of the ultrasonic probe are provided with the magnetic field protection rings for generating magnetic fields in the magnetic field protection rings. The protective cover is sleeved on a circumferential outer side of the rotating member where a detected position is located, and the front ends of the ultrasonic probe are arranged to penetrate through the magnetic fluid protective cover. A cavity formed between the magnetic fluid protective cover and the rotating member is filled with the magnetic fluid and the magnetic fluid is a liquid mixture solution.

Device and method for ultrasonic detecting of rotating member based on magnetic fluid coupling

A method for reducing and homogenizing residual stress of a metal frame based on elastic acoustic waves that includes determining an injection scheme of elastic acoustic waves based on residual stress distribution and material characteristics of a metal frame, where the injection scheme comprises at least one of the number of injection directions and corresponding injection direction(s), an excitation scheme and working parameters of the elastic acoustic waves; placing the metal frame in a substrate and fixing the inner and outer frames of the metal frame; assembling an excitation device for the elastic acoustic waves based on the determined excitation scheme of the elastic acoustic waves; injecting the acoustic waves into the metal frame from at least one direction; and performing the reduction and homogenization for multiple rounds if the reduction and homogenization of the residual stress of the metal frame in a single round does not meet the requirement.

Method for reducing and homogenizing residual stress of a metal frame based on elastic acoustic waves

An ultrasonic test device and test method for service stress of a moving mechanical component, where the device comprises an ultrasonic probe, a coupling fluid, a pressure-maintaining cover and universal wheels. The cover is vertically arranged above an inspected position of an inspected component, an interior of the pressure-maintaining cover is filled with coupling fluid, a bottom of the cover is provided with a structure permeable to the coupling fluid to form a coupling fluid film between the inspected position and the bottom of the cover, and a top of the cover is equipped with the ultrasonic probe. A detection part at a lower part of the ultrasonic probe extends into the coupling fluid of the cover and is vertical to the bottom of the cover without contact. The distance between the ultrasonic probe and the inspected component is kept unchanged through the universal wheels.

Ultrasonic test device and test method for service stress of a moving mechanical component

An ultrasonic monitoring probe for internal service stress of a marine structural component. The probe includes a detection wedge provided with two symmetrically arranged inclined surfaces at its top, two connecting channels vertical to the two inclined surfaces and penetrating through the detection wedge and provided with threaded holes close to the inclined surfaces and water storage cavities far away from the inclined surfaces, two ultrasonic transducers mounted in the threaded holes of the two connecting channels and configured for generating and receiving ultrasonic waves; two bottom rings located at a bottom of the detection wedge and arranged relative to the water storage cavities and configured for attachment to a surface of a detected component, a magnet disposed in a magnet placement hole arranged at a central position between the two connecting passages, and a monitoring device electrically connected with the two ultrasonic transducers.

Ultrasonic monitoring probe for internal service stress of a marine structural component

The present disclosure provides a device and a method for reducing and homogenizing residual stress during machining in which a workpiece is fixed, such as milling, boring, drilling and planning, with which high-energy acoustic waves are emitted to the workpiece via a tight contact between a plurality of high-energy wave exciters on a bench and a workpiece coated with a coupling medium, and residual stress inside the machined workpiece is reduced and homogenized through elastic wave energy generated in the workpiece by the high-energy acoustic waves. In this way, the purpose of reducing and homogenizing the residual stress while machining is achieved, realizing a stress-free machining, and the deformation of the workpiece during and after machining is minimized.

Device and a method for reducing and homogenizing residual stress of a workpiece generated during machining

The present disclosure provides a non-destructive detecting method for weld residual stress and a probe using the same, in the above method, detecting is performed by an ultrasonic detecting probe in contact with a detected portion of a workpiece to be detected, wherein when the weld residual stress of an intersecting curve weld bead of surfaces of cylinders is detected, for the same position of the intersecting curve weld bead, one of the residual stress of an axial direction of the cylinders and the residual stress of a circumferential direction of the cylinders is detected as a principal stress. For the surface of the cylinder at one side of the intersecting curve weld bead, the detecting of the weld residual stress of the surface of the cylinder can be realized only by using an ultrasonic detecting probe having one type of curved surface.

Non-destructive detecting method for weld residual stress and a probe using the same

A device and method for reducing and homogenizing residual stress of a component by an array of high-energy elastic waves. The device includes a tubular body consisting of at least two elements, multiple first through holes and a clamping device provided on an outer side of the tubular body. Exciters are connected with exciting wedges so that an end face of each of the exciting wedges is closely coupled to a surface of the component. A connection portion is coupled to an emitting end of each of the exciters, where the axis of the emitting end coincides with a normal line at a pressed surface of the component A multi-channel signal amplifier is electrically connected to each of the exciters and a multi-channel excitation control module is electrically connected to the multi-channel signal amplifier.

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Beijing, China

Yuren Lu