阅读说明：本技术 车载储氢气瓶结构健康在线监测系统和监测方法 (On-line monitoring system and monitoring method for structural health of vehicle-mounted hydrogen storage cylinder ) 是由 丁辉 晏井利 严岩 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种车载储氢气瓶结构健康在线监测系统和监测方法,其中监测系统包括设置于瓶体上的多个传感器节点、连接传感器节点的数据处理单元；所述传感节点包括：阵列导波模块,用于实现气瓶内胆和缠绕层缺陷全覆盖监测；相控阵超声模块,用于实现缠绕层分层定点监测；声发射模块,用于实现缠绕层纤维断裂监测。该监测系统可以实现对车载储气瓶上不同位置的内胆裂纹、缠绕层分层以及纤维断裂等气瓶典型缺陷的实时、在线监测。(The invention discloses an on-line monitoring system and a monitoring method for structural health of a vehicle-mounted hydrogen storage cylinder, wherein the monitoring system comprises a plurality of sensor nodes arranged on a cylinder body and a data processing unit connected with the sensor nodes; the sensing node includes: the array guided wave module is used for realizing full-coverage monitoring of the defects of the inner container and the winding layer of the gas cylinder; the phased array ultrasonic module is used for realizing layered fixed-point monitoring of the winding layer; and the acoustic emission module is used for realizing the monitoring of the fiber fracture of the winding layer. The monitoring system can realize real-time and on-line monitoring of typical defects of gas cylinders, such as liner cracks, winding layer delamination, fiber fracture and the like at different positions on the vehicle-mounted gas cylinder.)

1. A vehicle-mounted hydrogen storage cylinder structure health online monitoring system is characterized by comprising a plurality of sensor nodes arranged on a cylinder body and a data processing unit connected with the sensor nodes;

the sensing node includes: the array guided wave module is used for realizing full-coverage monitoring of the defects of the inner container and the winding layer of the gas cylinder; the phased array ultrasonic module is used for realizing layered fixed-point monitoring of the winding layer; and the acoustic emission module is used for realizing the monitoring of the fiber fracture of the winding layer.

2. The on-line monitoring system for structural health of a vehicle-mounted hydrogen storage cylinder according to claim 1, wherein the sensing node and the data processing unit are both made of flexible materials and form a flexible thin film layer.

3. The on-board hydrogen storage cylinder structural health online monitoring system of claim 1, wherein the distribution pattern of the plurality of sensor nodes includes but is not limited to axial, circumferential and star topology arrangement.

4. The on-line monitoring system for structural health of the vehicle-mounted hydrogen storage cylinder according to claim 1, wherein the array guided wave module is composed of a plurality of one-dimensionally arranged micro piezoelectric array elements and a low-frequency signal conditioning circuit, and the mode of the transmitted guided wave is controlled by the distance between the micro piezoelectric array elements.

5. The on-line monitoring system for structural health of the vehicle-mounted hydrogen storage cylinder according to claim 1, wherein the phased array ultrasonic module is composed of a plurality of micro piezoelectric array elements which are arranged in two dimensions and a high-frequency signal conditioning circuit, and the focal position of the transmitted ultrasonic wave is controlled by the delay rule of the excitation time between the micro piezoelectric array elements.

6. The on-line monitoring system for structural health of the vehicle-mounted hydrogen storage cylinder according to claim 1, wherein the acoustic emission module is composed of a single-point type micro piezoelectric array element and a signal receiving circuit, wherein the micro piezoelectric array element is always in a receiving working mode and monitors signals emitted when defects of the cylinder are generated in real time.

7. The on-line monitoring system for structural health of a vehicle-mounted hydrogen storage cylinder according to claim 4, wherein the operating frequency range of the low-frequency signal conditioning circuit is 100KHz to 500 KHz.

8. The on-line monitoring system for the structural health of the vehicle-mounted hydrogen storage cylinder according to claim 5, wherein the working frequency range of the high-frequency signal conditioning circuit is 1 MHz-5 MHz.

9. The on-line monitoring system for structural health of the vehicle-mounted hydrogen storage cylinder according to claim 1, wherein the data processing unit is further configured to process defect information obtained by the sensing node and transmit the defect information to a cloud computing platform.

10. The monitoring method of the on-line monitoring system for the structural health of the vehicle-mounted hydrogen storage cylinder based on any one of claims 1 to 9 is characterized by comprising the following steps:

s1, the acoustic emission module is always in an open state, and all possible signals are monitored;

s2, the low-frequency signal conditioning circuit emits a sine wave signal with the frequency of f1, and the array guided wave module is excited to detect cracks in the liner;

s3, the low-frequency signal conditioning circuit emits a sine wave signal with the frequency of f2, and the array guided wave module is excited to realize detection of the layering defect of the winding layer;

and S4, the high-frequency signal conditioning circuit emits a negative square wave signal to excite the phased array ultrasonic module to realize accurate quantification of the layering defects of the winding layer.

Technical Field

The invention relates to an on-line monitoring system for structural health of a vehicle-mounted hydrogen storage cylinder, and belongs to the technical field of structural health monitoring of hydrogen storage cylinders.

Background

Hydrogen energy safety is an important bottleneck that restricts the development of hydrogen fuel cell vehicles. When the vehicle-mounted hydrogen storage cylinder is used, internal damage is easily caused due to long-term vehicle-mounted vibration, hydrogen charging and discharging circulation, vehicle accidents and the like. Since hydrogen gas is the smallest volume molecule, hydrogen leakage is very likely to occur at the site of injury. Hydrogen is also the gas with the widest explosion limit (4.0% -75.6%), and leaked hydrogen can cause greater potential safety hazard. Therefore, the special detection technology for the vehicle-mounted hydrogen storage cylinder is developed, the internal defects of the cylinder are found in time, explosion accidents caused by hydrogen leakage are avoided, and the method has important significance on the safety of hydrogen energy automobiles.

The prior reported patents include the detection of vehicle-mounted gas cylinders by using various non-destructive detection methods such as ultrasound, rays, eddy current and the like. However, some of the methods reported are to introduce a detection sensor into the interior of the gas cylinder for detection, such as ultrasonic and eddy current methods, which require releasing hydrogen gas from the cylinder and detaching the cylinder to complete detection; some have certain dangers, such as ray detection methods. Generally, the conventional detection method is generally large in size, is mainly used for periodic off-line detection, and is not suitable for on-line detection in a vehicle-mounted mode. On-line testing necessitates the development of miniaturized test equipment.

Another difficulty with on-board cylinder inspection is the need for full coverage inspection of different types of defects. The main body of the vehicle-mounted hydrogen storage cylinder consists of an inner container and a carbon fiber winding layer, wherein the defects of the inner container mainly appear on the inner wall and are expressed as inner wall cracks; the defects of the carbon fiber winding layer are complicated, one part is cracks caused by fiber breakage, and the other part is debonding and delamination between fiber layers caused by weak bonding force. Therefore, on-line detection needs to integrate a plurality of methods to form a monitoring network so as to realize all detection and real-time monitoring of defects at different positions and different types. In summary, it is highly desirable to develop a miniaturized vehicle-mounted online detection network system capable of detecting and quantifying different types of defects.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides an on-line monitoring system and a monitoring method for the structural health of a vehicle-mounted gas cylinder, and provides a set of real-time on-line structural health monitoring solution for typical defects of gas cylinders, such as liner cracks, winding layering, fiber fracture and the like at different positions of the vehicle-mounted gas cylinder.

The technical scheme is as follows: the invention provides an on-line monitoring system for structural health of a vehicle-mounted hydrogen storage cylinder, which comprises a plurality of sensor nodes arranged on a cylinder body and a data processing unit connected with the sensor nodes;

the sensing node includes: the array guided wave module is used for realizing full-coverage monitoring of the defects of the inner container and the winding layer of the gas cylinder; the phased array ultrasonic module is used for realizing layered fixed-point monitoring of the winding layer; and the acoustic emission module is used for realizing the monitoring of the fiber fracture of the winding layer.

The sensing nodes and the data processing unit are made of flexible materials and form a flexible thin film layer.

The distribution pattern of the plurality of sensor nodes includes, but is not limited to, axial, circumferential, and star topology arrangements.

The array guided wave module is composed of a plurality of miniature piezoelectric array elements which are arranged in one dimension and a low-frequency signal conditioning circuit, and the mode of the transmitted guided wave is controlled through the space between the miniature piezoelectric array elements.

The phased array ultrasonic module is composed of a plurality of two-dimensionally arranged miniature piezoelectric array elements and a high-frequency signal conditioning circuit, and the focal position of the transmitted ultrasonic wave is controlled through a delay rule of excitation time among the miniature piezoelectric array elements.

The acoustic emission module comprises a single-point type miniature piezoelectric array element and a signal receiving circuit, wherein the miniature piezoelectric array element is always in a receiving working mode, and signals sent out when defects of the gas cylinder are generated are monitored in real time.

The working frequency range of the low-frequency signal conditioning circuit is 100 KHz-500 KHz.

The working frequency range of the high-frequency signal conditioning circuit is 1 MHz-5 MHz.

The data processing unit is further used for processing the defect information obtained by the sensing nodes and transmitting the defect information to the cloud computing platform.

On the other hand, the invention also provides a monitoring method based on the monitoring system, which comprises the following steps:

s1, the acoustic emission module is always in an open state, and all possible signals are monitored;

s2, the low-frequency signal conditioning circuit emits a sine wave signal with the frequency of f1, and the array guided wave module is excited to detect cracks in the liner;

s3, the low-frequency signal conditioning circuit emits a sine wave signal with the frequency of f2, and the array guided wave module is excited to realize detection of the layering defect of the winding layer;

and S4, the high-frequency signal conditioning circuit emits a negative square wave signal to excite the phased array ultrasonic module to realize accurate quantification of the layering defects of the winding layer.

Has the advantages that: the on-line monitoring system and the monitoring method for the structural health of the vehicle-mounted hydrogen storage cylinder disclosed by the invention have the following beneficial effects:

(1) in the monitoring system provided by the invention, a plurality of sensor nodes carry out full-coverage detection on the gas cylinder in a network arrangement and real-time monitoring mode. Therefore, the method for detecting the internal defects of the traditional gas cylinder only by off-line detection is changed, the online detection of the internal defects of the gas cylinder is realized, and the method is favorable for monitoring the structural health state of the hydrogen storage gas cylinder in real time.

(2) The invention integrates three modes of ultrasonic guided wave, phased array and acoustic emission, and can realize three detection modes on one sensor node, and the three detection modes respectively have good detection capability on different defects such as liner cracks, winding layer delamination, fiber fracture and the like. Therefore, the three detection modes are integrated, and the defects of different types can be completely detected.

(3) The present invention also employs a frequency-division mode to avoid interference between signals. The array guided wave adopts a low-frequency sine wave, and the phased array ultrasound adopts a high-frequency negative square wave. When all signals are monitored by acoustic emission, the actively transmitted waveform can be compared with the passively received waveform so as to avoid the influence of other two modules.

Drawings

FIG. 1 is a schematic diagram of the structure health online monitoring system of the vehicle-mounted hydrogen storage cylinder disclosed by the invention;

FIG. 2 is a schematic diagram of the arrangement of piezoelectric array elements of an array guided wave module;

FIG. 3 is a schematic diagram of piezoelectric array element arrangement of a phased array ultrasonic module;

FIG. 4 is a flow chart of the method for on-line monitoring of structural health of a vehicle-mounted hydrogen storage cylinder disclosed by the invention.

Detailed Description

The invention is further elucidated with reference to the drawings and the detailed description.

As shown in figure 1, the diameter of the vehicle-mounted hydrogen storage cylinder is 400mm, the structural health online monitoring system comprises 30 network sensing nodes which are distributed and fixed on a cylinder body and a data processing unit which is connected with each sensing node, the sensing nodes comprise an array guided wave module which realizes defect full-coverage detection of a cylinder liner and a winding layer, a phased array ultrasonic module which realizes layered fixed-point detection of the winding layer and a sound emission module which realizes fiber fracture monitoring of the winding layer, and the sensing nodes are arranged in a star topology arrangement mode as shown in figure 1.

The array guided wave module is composed of micro piezoelectric array elements arranged in one dimension and a low-frequency signal conditioning circuit, and as shown in fig. 2, the mode of the transmitted guided wave is controlled by the space between the micro piezoelectric array elements.

The phased array ultrasonic module is composed of micro piezoelectric array elements which are arranged in a two-dimensional mode and a high-frequency signal conditioning circuit, and as shown in fig. 3, the focal position of transmitted ultrasonic waves is controlled by a delay rule of excitation time among the micro piezoelectric array elements.

The acoustic emission module comprises single-point type miniature piezoelectric array element and signal receiving circuit, and miniature piezoelectric array element is in receiving mode all the time, monitors the signal that sends when the gas cylinder defect produces in real time.

In the embodiment, the working frequency range of the low-frequency signal conditioning circuit is 100 KHz-500 KHz; the working frequency range of the high-frequency signal conditioning circuit is 1 MHz-5 MHz.

The flow chart of the online monitoring method based on the online monitoring system is shown in fig. 4, and firstly, the acoustic emission module is always in an open state to monitor all possible signals; secondly, a low-frequency signal conditioning circuit emits a sine wave signal with the frequency of 250KHz, and an array guided wave module is excited to realize the detection of the internal cracks of the liner; a sine wave signal with the frequency of 150KHz is transmitted again, and the array guided wave module is excited to realize the detection of the layering defect of the winding layer; finally, a high-frequency signal conditioning circuit emits a negative square wave signal to excite the phased array ultrasonic module to realize accurate quantification of the layering defects of the winding layer; and the data processing unit processes the defect information obtained by the network sensing node and transmits the defect information to the cloud computing platform.