Fully Contactless Damage Assessment of Insfastructures
Autonomous and Rapid Bridge Inspection System for Internal Damage
The techniques provide an effective non-destructive approach to evaluate concrete structures, but we need rapid and non-obtrusive data collection and accurate interpretation to enable effective and meaningful application to the infrastructure.
The objectives of this effort are:
3-D image of experiment results indicate internal defect (delamination) in the Bridgedeck. The wave interpretation of MASW air-coupled ultrasonic data can distinguish delaminated regions of concrete. Multiple Lamb wave data can be used accurately image delamination position. The method shows promise for rapid and effective bridge deck evaluation. Dispersion curve stack assembled to give 3D image
Real-time Monitoring Internal Damage of Numerous Rail Concrete cross-tie
Develop sensitive NDT test approach for cost effective inspection.
- Multi-sensor MEMS array receivers, provides consistent data from rail tie structures.
- Short-time-interval average signal (STIA) analysis allows for clear distinctions between RSD damage levels
- The large offset (250mm liftoff distance from surface) testing configuration provides some ability to detect among different damage levels with moving (Real-time scanning).
Incoherent Backscattering Energy Approach to Characterize Internal Microcracking Damage in Concrete (In-situ measurement)
Air-launched ultrasonic surface backscatter data provide distinction between different extents of distributed microcracking damage in concrete. Data from conventional forward propagating coherent pulse analysis are not able to distinguish the damage states.
From microcracks to macrocrack, the technique allow very sensitivity to with 95% confidence leveled statistically difference
The contactless ultrasonic testing approach that uses backscatter measurements to characterize distributed cracking damage in concrete structures. Conventional NDE systems indicate relative value, poor sensitivity, have potentially slow speed measurements. Efforts to overcome both issues by employing rapid ultrasonic incoherent backscatter phenomena are introduced here. This technique
The module allows bandwidth and frequency control by a specific ceramic resonator. The ceramic resonator controls the central frequency of the capacitive transducer between 30 and 80 kHz. The microchip in the module controls pulse duration. The main microchip (generic microcontroller) for the pulse control is the ATMEL Tiny45, which is controlled with an open source code communicating with a computer through the AVR ISP connector as shown Figure . The 7805 IC regulator in the module maintains a stable and constant voltage level, reducing the electric noise in the built-in commercial module. Module A is simple and easy to construct, although the pulse duration must be at least 10 cycles long owing to limited sampling resolution of the microchip. Thus it is ideal for tone burst signals at a selected central frequency.
It generates arbitrary electrical excitation signals. A generic microcontroller, such as a single–board microcontroller or PIC (Peripheral interface controller), cannot create high frequency arbitrary waves having very low sampling rate, and as such are unsuitable for our purposes. Rather, field-programmable-gate-arrays (FPGA) shown in Figure are used to generate the arbitrary signal. FPGA operate using customizable logic gates instead of writing instruction sets to the board, like a microcontroller does. The Module B FPGA uses a Papilio One board with a Spartan 3E FPGA chip. Logic gates exhibit very fast response times, in the order of nanoseconds; this is sufficient to create arbitrary pulses up to a frequency of 200 kHz. Furthermore, it is easily programmed so any waveform can be produced. Programming is carried out using Xilinx’s ISE Design Suite. Although the module is more complicated in its design, it is suitable for generating arbitrary waves and chirp signals. The FPGA out signal connected to BJT in circuitry board of modified sending transducer
Concrete Match-curing Project
Match curing (MC) is a process (whereby concrete sample are cured with the same temperature history )as the mass concrete structure providing in-place strength estimates. We developed and built new a MC system using programming, that shows the effect of temperate control precision for strength estimate.