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Structures and Materials Laboratory Testing Capabilities
The University of Miami, Structures and Materials Laboratory (SML) has been an integrated educational, research, and testing service facility within the College of Engineering, under the Department of Civil and Architectural Engineering since 1959.
SML has an integrated structural floor area of approximately 1000 sq. ft. for testing and evaluation of components and systems. The integrated SML facilities include strategic areas for materials characterization, structural evaluation, and specimen fabrication/preparation. SML has dedicated test frames, equipment, and instruments available to us for many types of experimental projects or testing solutions.
Since 2012, the SML has demonstrated compliance with ANS/ISO/IEC Standard 17025 “General requirements for the competence of testing and calibration laboratories” and has been an accredited testing laboratory. At the time, SML was the only US University accredited as a testing laboratory. The SML has continued to push boundaries within the industry through innovation and continual improvement.
Structures Laboratory The laboratory has a structural floor area of approximately 820 sq. ft for testing and evaluation of components and systems. The laboratory is also approximately 55 ft long, which is adequate for the testing of large scale structural members. Further, test specimens and supporting elements can be anchored to the integrated structural floor using the embedded sleeve anchors. The laboratory is also equipped with an overhead crane, which can be utilized for handling the specimens. The structures laboratory offers the following equipment:
· 133-kN (30-kip) Instron, mechanical driven universal test frame, PC controlled via Blue Hill software testing system;
· 890-kN (200-kip) Baldwin, mechanical driven universal test frame with data acquisition system;
· 1780kN (400-kip) SATEC, hydraulic machine to conduct static loading in compression;
· 240-kN (55-kip) fatigue-rated MTS actuator mounted on a dedicated frame (Figure 1. It can be combined with up to four NI C Series I/O modules for a custom analog input, analog output, digital I/O, and counter/timer measurement system.
One Single Chassis Data Acquisition System – This USB single module carrier, highly portable solution for NI C Series modules. It can be combined with one NI C Series I/O modules for a custom analog input, analog output, digital I/O, and counter/timer measurement system. This data acquisition system is compatible with the following cDAQ modules, with the exception of the universal strain modules.
The cDAQ module include:
· Two 8-channel (16 channels total) universal strain gauge analog-input moduli with an independent 0-2.5 V programmable excitation source per channel, and quarter, half, and full-bridge completion capabilities. Typical strain-based sensors that can be interfaced with the module include electrical resistance strain gauges, load cells, strain-based displacement transducers
· Five 4-channel (20 channels total) universal modules designed for multipurpose testing. They can measure several signals from sensors such as strain gages, RTDs, thermocouples, load cells, and other powered sensors. Measurement ranges differ for each type of measurement and include up to ±60 V for voltage and ±25 mA for current.
· One 4-channel current input module designed to measure 5Arms nominal and up to 14A peak on each channel with channel-to-channel isolation. It can measure power and energy consumption for applications such as appliance and electronic device test as well as signals from current output sensors.
· One 4-channel simultaneously updating analog output module. It can source voltages from -10V – 10V.
· One 4-channel simultaneous bridge module. It contains all the signal conditioning required to power and measure up to four bridge-based sensors simultaneously.
Figure 3 – National Instruments Compact DAQ (cDAQ) portable data acquisition system configuration.
Sensors – The following DC-excitation analog-output sensors have been acquired:
· 4x ±0.5 in. DC-LVDT displacement transducers
· 2x ±1.0 in. DC-LVDT displacement transducers
· 4x ±2.0 in. DC-LVDT displacement transducers
· 2x draw-wire displacement transducers with 4.0 in. measuring range
· 1x draw-wire displacement transducer with 12.0 in. measuring range
· 15x linear potentiometers with 1.5 in. measuring range
· 4x ±10° electronic inclinometers
· 1x 15 psi pressure transducer
The following strain-based sensors have been acquired:
· Several electrical strain gauges with gauge lengths from 0.2 to 2 in.
· 2x 25 kip donut load cells
· 2x 50 kip donut load cells
· 2x 100 kip donut load cells
· 2x 200 kip donut load cells
· 1x 300 kip canister load cell
· 6x ±10 kip tension/compression load cells
· 10x ±6000 micro-strain PI-gauge displacement transducers
· 1x 1.4 in Extensometer with .28 in travel
· 1x 2 in. gauge length Extensometer with 0.5 in. travel
· 1x 2 in. gauge length Extensometer with 1 in. travel
· 1x 4 in. gauge length Extensometer with 0.5 in. travel
· 2x 0.1 in. gauge length displacement clip gauges
· 8x Bridge Sensors: complete signal conditioning system on a card designed expressly for either half of full bridge transducers
JAMES BOND Tester – Also known as a pull off adhesion test, it measures the bond strength or tensile strength of concrete, asphalt, tile, concrete repair, or other overlay material by the direct tension or pull off method. This equipment can, measure the near surface strength of a substrate in order to determine the substrates quality, determine the bond strength of a repair or overlay material after it is applied to the substrate and determine the tensile strength of a repair, overlay or adhesive after the material is applied to the surface, including but not limited to shotcrete, tile, epoxies, paint and other repair materials or coatings.
Materials Laboratory Adjacent to and connected with the structures laboratory, the materials laboratory is available for the preparation of coupon specimens and materials testing. The materials laboratory offers the following equipment:
· 40 kN (9-kip) 318.25S MTS, servo-hydraulic high-rate (impact) test frame capable of conducting static, high-cycle fatigue, and impact loading (up to 18 m/sec) in tension, compression, and flexure (Figure 4(c)) to adjust the test head for different specimen lengths, capable of conducting static and high-cycle fatigue loading in tension, compression, and flexure. Attachments and fixtures include extensometers, LVDTs, crack opening displacement (COD) gage, AE sensors, and two magnifying microscopes with video signal up to 200 times.
The structures laboratory has non-destructive evaluation (NDE) equipment to examine off site and in site, the condition of a given structural system. This equipment includes:
Acoustic Emission System (AE) – The Sensor Highway II System™ is an Acoustic Emission (AE) monitoring system with 16 high-speed channels resonant and 16 standard parametric input channels (expandable to over 100). The system is designed for unattended and remote monitoring use in structural health monitoring management and condition monitoring applications for deployment in laboratory and field testing. It is rated for outdoor use and comes equipped in a rugged weather proof NEMA 4 enclosure. The key feature of the Sensor Highway II System™ is its highly flexible sensor fusion interface for input and processing, using a variety of sensors, as described below.
The sensors, components and software utilized in the AE system include:
· R6I and R15I sensors – convert a stress (sound) wave to an electrical signal with high sensitivity and resonant type with an integrated amplifier.
· R6D Sensors – are general purpose differential sensors designed to isolate the sensing terminals electrically from the cavity. This electrical isolation makes the sensor particularly useful for applications where high background electrical noise is a major concern.
· WD Sensor – A true differential wideband sensor with a very high sensitivity and bandwidth. Differential sensors differ from their general purpose counterparts by employing two sensing elements with opposite polarization directions. The two signal leads feed into a differential pre-amplifier which eliminates common-mode noise resulting in a lower noise output from the pre-amplifier.
· Wideband sensors – for applications where high fidelity AE response is required, while helping determine the predominant frequency band of AE sources for noise discrimination.
· Voltage Preamplifiers – used with the wide-band sensors with 0/20/40 dB gain, single-ended and differential sensor inputs, bandwidth changeable plug-in filter.
· R3I‑AST, R6I‑AST and R15I‑AST are integral preamplifier AE sensors. They are specifically engineered to attain high sensitivity and have the capability to drive long cables without the need for a separate preamplifier. Their integrated Auto Sensor Test (AST) capability allows these sensors to pulse as well as receive. This feature lets you verify the sensor coupling and performance at any time throughout the test.
· PCI-2 AE System (18 AE bit) – 2-channel data acquisition and digital signal processing system, with superior low noise and low threshold performance, through the use of a PAC designed 18-bit A/D conversion scheme, 40 MSample/second acquisition with real time sample averaging techniques.
· AEwin™ – 32 bit Windows based Data Acquisition and Replay program, capable of running the PAC, DiSP, SAMOS, PCI-2, MISTRAS or SPARTAN based products. This software has real time AE and parametric data acquisition. It includes front end and graph filtering, feature extraction, alarm output, multiple location functions, 2-D & 3-D graphing, clustering, waveform processing, correlation analysis, FFT, flexible graphing, graph printing and exporting, line display of hit information, hit statistics and replay functions.
· NOESIS 4.1 – program works in conjunction with AEwin to allow real-time neural network classifications for supervised pattern recognition, while allowing data viewing and manipulation, which supply tools for analyzing, filtering and classifying AE hits and waveforms that are acquired with PAC’s LOCAN, SPARTAN, LAM, DiSP, and MISTRAS systems
· R-METER System – This reinforcement bar locator system has a single sensor and can determine bar size up to 4.5 in deep and can locate it up to 8 in deep. It is used in conjunction to the COR-MAP System.
COR-MAP System – This is a basic half-cell system used to locate corroding steel reinforcement. This equipment has a detachable electrode extension piece, which facilitates measurements in hard to reach locations. The high impedance digital meter used with the system is designed for tough field conditions, while the electrode is designed for use on horizontal, vertical and inverted positions.
The Structures and Materials Laboratory’s scientists are leaders in providing interaction, consulting and testing services of materials. Our laboratory is equipped with modern and innovative machines that allow our professional experts to offer the best advice to our clients.
