Universal tester

The labor-intensive nature of polymer tensile and flexure tests makes them logical candidates for automation. We have developed a fully automated instrument for performing these tests on rigid materials. The instrument is comprised of an Instron universal tester, a Zymark laboratory robot, a Digital Equipment Corporation minicomputer, and custom-made accessories to manipulate the specimens and measure their dimensions automatically. Our system allows us to determine the tensile or flexural properties of over one hundred specimens without human intervention, and it has significantly improved the productivity of our laboratory. This paper describes the structure and performance of our system, and it compares the relative costs of manual versus automated testing. 

Figure 1. Overall instrument layout showing (A) Instron 1125 universal tester (B) Zymark laboratory robots (C) Specimen bar magazine (D) Specimen bar measuring device.

Mechanical Properties. Mechanical properties obtained on the cured resins included tensile strength and fracture toughness. Tensile tests were run on an Instron model 1122 Universal Tester with a crosshead speed of 0.02 /minute. Tests were run on dry and saturated samples in air. Fracture toughness (K ) values have been obtained using a MTS 610 Materials Testing System at 0.02 /minute at ambient and elevated temperatures in air. The compact tensile specimens tested were 0.5 x 0.5 x 0.125 in dimension. Mechanical properties data are based on the results from four or more tests run at each condition. 

Flexural Properties. Both flexural modulus and flexural strength values were obtained. These values were measured at 23 °C and also over a range of temperatures for the MBAS polymer (see Figure 4). In the flexural tests, a molded bar is tested as a simple beam, the bar resting on two supports, and the load is applied midway between. The test is continued until rupture or 5% strain, whichever occurs first. The test fixture is mounted in a universal tester, and the tester is placed in an appropriate temperature environment. 

Two aspects of texture were considered firmness of the intact segment and toughness of the carpellary membrane. Both were measured on stored segments with an Instron model 1011 Universal Tester (Instron Corp., Canton MA 02021) set on compression mode. Firmness was determined by crushing a pair of segments in an Ottowa Texture Measurement System to 3 mm final thickness. Crushed segments were then transferred to a Kramer Shear Cell and the force necessary to shear the membranes determined. 

Mechanical properties of the membranes were preliminarly tested and compared to those exhibited by cell-free poly-sulphone fibres. The Young modulus, E wet, and the ultimate properties of the membranes were estimated by a stress-strain analysis carried out on a Instrom Universal Tester. The average value of the Young modulus was found lower by a factor of about 2.5 relative to the average value of the cell-free fibres. 

At various time intervals, animals were sacrificed and specimens of the wound contents as well as of an intact skin area about 5 cm from the wound perimeter were either removed for mechanical testing, or were fixed prior to processing for histological staining. Tensile specimens were stored in physiological saline at 4°C and were stretched in an Instron Universal Tester Model TM at 100% min at room temperature within 24 h of sacrifice. Specimens for histological study were stained with hematoxylin and eosin and viewed in a light microscope. 

The in vitro BSR was evaluated by determining the breaking strength of the sutures after incubation in a phosphate buffered solution at pH 7.4 and 37°C for predetermined periods of time. The in vivo BSR was determined on explanted sutures that have been implanted subcutaneously in rats for predetermined periods according to the animal protocols described in a previous report. The linear breaking strength of the explanted sutures as well as those exposed to the phosphate buffer was determined using an MTS MiniBionix Universal Tester (Model 858). 

Four-point bend tests were performed at room temperature and at 1400°C. All bending tests had an upper span of 10 mm and a lower span of 30 mm. An Instron-type universal tester was used for bending tests, with a constant cross head of 0.2 mm/min. Figure 5.36 shows the dimensions and coordinate system of the beam specimen with ground surface in a four-point bend test. 

Crimp extension refers to the extent to which the graft or biotextile stmcture stretches under longitudinal tension. A spedmen of known relaxed length is extended on a mechanical tester, such as an Instron Universal Tester, so as to remove most of the crimps by applying a standard constant load of 1.2 N. The amount of crimp extension is calculated from the difference between... 

NMR and Si-NMR spectra were obtained in CDCI3 with chemical shifts (6) referenced to tetramethylsilane. Elemental silicon was analyzed by Galbraith Laboratories. Instron Universal Tester (Model 1000) was used to measure the tensile properties of the cured coatings. Pull-off adhesion tester (Elcometer, Model 106) was used to evaluate the adhesion of the coatings to aluminum substrates. 

Figure 9.13 Universal tester load frame, set up for tensile testing of rigid plastics.

The dynamic shear testing of rubber-to-metal bonds was done with a Plastechon Universal tester. This machine is an electro-hydraulic floor model with a 20,000-lb capacity. (Fig. 1.) It has additional interchangeable actuator/piston sleeve assemblies available in 2,500, 5,000 and 10,000-lb capacities. The speed range of the tester varies with the capacity. The range under 20,000-lb actuator service is from 2.0-3000 in/min, with speed range being... 

Mechanical test was done using the Instron 4400 Universal Tester to measure the tensile strength at the point of breakage for each sample. Tensile tests were carried out at room temperature, according to the ASTM D882 type V. A fixed crosshead rate of 12.5 mm/min was utilized in all cases, and the results were taken as an average of five tests. 

Methylamines are colorless liquids that are volatile under atmospheric conditions. The amines have threshold odor limits of less than 10 ppm at low concentration they smell fishy, whereas at high concentration they smell like ammonia. Nevertheless, their odor is not a reliable means of detecting methylamines because the nasal membrane can be rapidly desensitized. The MSA Universal Tester with Detector Tube 92115 can be used to detect less than 10 ppm amines in air. 

Tensile and flexural analyses were performed on the Instron Universal Tester Model 4301 in aceotdance to ASTM D638 and ASTM D747, respectively. Fleximal tests were also done at 2 mm/minute and tensile tests at 50 mm/minute. 

The dumbbell-shaped samples of PET/MMT with 2 mm thickness were injection molded. The uniaxial tensile tests of samples were carried out at three stretch rate (7.5, 10 and 12.5 mm/s crosshead speed) and the temperatures above the glass transition temperature with the computerized universal tester (model tensiTECH) manufactured by Tech Pro. Inc. The temperature range spans from 85 °C to 105 °C. An environmental chamber was used to bring the sample to the desired experimental temperature. The samples were heated inside an oven for about 15 min before being stretched. 

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