Axial magnetic field loading device with adjustable strength

Abstract

The invention relates to an impedance tube sound insulation measurement technology, in particular to an axial magnetic field loading device with adjustable strength. The device is composed of a cylindrical pipe, a heat dissipation baffle, an enameled copper wire, a locking device, a piston rod, an adjustable lifting device and a direct-current power supply. The axial magnetic field loading device with the adjustable strength is connected through a tightening device, the cylindrical pipe and the impedance pipe are tightly connected, the problem of sound leakage in an impedance pipe measuring system is solved, and disassembly and assembly are convenient and fast. The axial magnetic field loading device with adjustable strength realizes loading of a uniform magnetic field, and the magnetic field strength is quantitatively controlled through input current. The heat dissipation baffle solves the problem that the sound insulation measurement precision is influenced because electric heat generated in a long-time experiment cannot be dissipated. An external adjustable uniform magnetic field test environment can be provided on the premise of ensuring the measurement precision.

Description

technical field [0001] The invention relates to an impedance tube sound insulation measurement system, which is an axial magnetic field loading device with adjustable strength. Background technique [0002] Existing impedance tube sound insulation measurement systems are limited to sound insulation measurements without the action of other fields, and most of them are suitable for traditional passive sound insulation structures. Once the traditional passive sound insulation structure is made, its equivalent parameters are fixed, and the sound insulation frequency band is narrow, so it is difficult to adapt to the complex and changeable noise environment. In order to enhance the adaptability of sound insulation materials to complex acoustic environments, active sound insulation structures need to be further developed. Active sound insulation materials based on magnetic field control using materials such as magnetorheology are developing rapidly. The performance of such active ...

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Problems solved by technology

[0003] At present, there are three main ways to load the magnetic field in the impedance tube sound insulation experiment. The first is to put the ring permanent magnet on the impedance tube, and this form of magnetic field cannot be adjusted effectively; the second is to put the electromagnetic field device and the sound insulation test piece together. Placed together in the impedance tube, this method will make it difficult to take out the wire and the wire will interfere with the propagation of the plane wave in the impedance tube; the third is a magnetic field loading device formed by winding a coil outside the impedance tube, because the coil is energized. Electric heating will affect the sensitivity of the sensor, and then affect the measurement accuracy of the sound insulation experiment

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