Impact resistance test system for helmet based on polyvinylidene fluoride piezoelectric sensor array

2022 ◽  
pp. 1-32
Author(s):  
Qiyue Li ◽  
Xiaomu Liao ◽  
Xing Huang ◽  
Xinao Wei ◽  
Xiang Zhang
Keyword(s):  
Polyvinylidene Fluoride ◽  
Sensor Array ◽  
Impact Resistance ◽  
Piezoelectric Sensor ◽  
Test System ◽  
Resistance Test

Baseline-free sensor fault detection for piezoelectric array

2021 ◽  
pp. 1045389X2110188
Author(s):  
Qibo Mao ◽  
Yuande Wang ◽  
Shizuo Huang
Keyword(s):  
Prior Knowledge ◽  
Frequency Response Function ◽  
Sensor Array ◽  
Piezoelectric Element ◽  
Piezoelectric Sensor ◽  
Steel Beam ◽  
Sensor Fault ◽  
Pass Filter ◽  
Sensor Fault Detection ◽  
High Pass

In this study, a new methodology is presented to detect the sensor fault for piezoelectric array based on the filtered frequency response function (FRF) shapes. The proposed method does not require prior knowledge about healthy piezoelectric array. First, the imaginary parts of FRFs from the piezoelectric array during vibration are measured and normalized to obtain the FRF shapes in different frequencies. Then the irregularities in these FRF shapes are extracted by using high-pass filter with properly chosen cut-off frequency. These abnormal irregularities on the filtered FRF shape curves indicate the location of the faulty sensor, due to the irregularity of FRF shapes introduced by the faulty piezoelectric element. The proposed sensor fault method is experimentally demonstrated on a clamped-clamped steel beam mounted with piezoelectric buzzer array. Two common piezoelectric sensor fault types including sensor breakage and debonding are evaluated. The experimental results indicate that the proposed method has great potential in the detection of the sensor fault for piezoelectric array as it is simple and does not require the FRF data of the healthy sensor array as a baseline.

An airflow sensor array based on polyvinylidene fluoride cantilevers for synchronously measuring airflow direction and velocity

2019 ◽  
Vol 67 ◽  
pp. 166-175 ◽  
Author(s):  
Jie Hu ◽  
Hanmin Peng ◽  
Ting Mao ◽  
Tingyu Liu ◽  
Mingsen Guo ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Sensor Array ◽  
Airflow Sensor

Fretting Characteristics and Environmental Reliability of Au-Sn Contact Pairs

2019 ◽  
Vol 953 ◽  
pp. 115-120 ◽  
Author(s):  
Xue Yan Lin ◽  
Hai Tao Hao ◽  
Min Xie
Keyword(s):  
Contact Resistance ◽  
Ambient Temperature ◽  
Contact Force ◽  
Salt Spray ◽  
Test System ◽  
Resistance Test ◽  
Contact Pair ◽  
Simulation Experiments ◽  
Micro Motion ◽  
Environmental Simulation

Based on the laboratory micro-motion contact resistance test system, fretting characteristics of the two contact pairs of gold-plated probe and tin-plated samples, gold-plated samples and tin-plated probe, is carried out at different plating thickness, contact force and temperatures. The contact pairs after the fretting experiment were subjected to temperature and humidity test and salt spray test to analyze its environmental reliability. 0.76μmAu-Sn has better fretting characteristics than 4μm Sn-Au. When the contact force is greater than or equal to 100 gf, the two kinds of contact pair exhibit good fretting characteristics. Thickness of sample plating is more important than that of probe. The influence of ambient temperature on fretting contact performance is the weakest. The increase of contact resistance of contact pair 4μm Sn-Au is higher than that of 0.76μmAu-Sn after accelerated environmental simulation experiments.

scholarly journals Data Compression Approach for Long-Term Monitoring of Pavement Structures

2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Mario Manosalvas-Paredes ◽  
Nizar Lajnef ◽  
Karim Chatti ◽  
Kenji Aono ◽  
Juliette Blanc ◽  
...  
Keyword(s):  
Data Compression ◽  
Polyvinylidene Fluoride ◽  
Piezoelectric Sensor ◽  
The Novel ◽  
Novel Approach ◽  
Damage Tracking ◽  
Pavement Structures ◽  
Micro Deformation ◽  
Reference Measurements

Pavement structures are designed to withstand continuous damage during their design life. Damage starts as soon as the pavement is open to traffic and increases with time. If maintenance activities are not considered in the initial design or considered but not applied during the service life, damage will grow to a point where rehabilitation may be the only and most expensive option left. In order to monitor the evolution of damage and its severity in pavement structures, a novel data compression approach based on cumulative measurements from a piezoelectric sensor is presented in this paper. Specifically, the piezoelectric sensor uses a thin film of polyvinylidene fluoride to sense the energy produced by the micro deformation generated due to the application of traffic loads. Epoxy solution has been used to encapsulate the membrane providing hardness and flexibility to withstand the high-loads and the high-temperatures during construction of the asphalt layer. The piezoelectric sensors have been exposed to three months of loading (approximately 1.0 million loads of 65 kN) at the French Institute of Science and Technology for Transport, Development and Networks (IFSTTAR) fatigue carrousel. Notably, the sensors survived the construction and testing. Reference measurements were made with a commercial conventional strain gauge specifically designed for measurements in hot mix asphalt layers. Results from the carrousel successfully demonstrate that the novel approach can be considered as a good indicator of damage progression, thus alleviating the need to measure strains in pavement for the purpose of damage tracking.

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