Static compression test

DSC studies have shown that multifunctional monomers react quickly to form densely crosslinked networks from liquid monomer solutions. However, even a small amount of unreacted monomer can effectively plasticize a crosslinked network, rendering it more pliable. Eor this reason, mechanical analysis was combined with DSC studies to characterize the physical changes occurring in the proposed dimethacrylate system as polymerization proceeds. Static compression tests (Perkin-Elmer, DMA7e) were completed on disks (d = 11.5 mm, t = 1.7) immediately after they were irradiated for varied times. 

The static modulus and dynamic storage modulus were investigated for some open-celled PE foams by static compression tests and dynamic viscoelastic measurements in compression mode. Experimental data were compared with theoretical predictions. 8 refs. 

This curious behavior, wherein the 0o.5 decreases or increases as porosity increases, might be explained by the shock pressure propagation in addition to the mechanical strength varying with the porosity and silicate contents. The mechanical strength obtained by the static compression tests is shown in Figure 9 for snow and snow-silicate mixture... 

Figure 9 Porosity dependence of mechanical strength (a) derived by static compression tests for snow and snow-silicate mixture.

Table 10.1 Results of static compression tests single impact case [1]... 

Deformation properties are derived from a static compression test. Young s modulus is defined as the ratio of an axial stress and the resulting axial strain ... 

Results of uniaxial strain static and gas gun compression tests on syntactic foam have been conducted. The foam was buoyant and composed of hollow glass microspheres (average diameter 100 microns) embedded in an epoxy plastic. Static testing consists of compressing a 0.25 cm x 2.5 cm dia. wafer between carefully aligned 2.5 cm dia. steel pistons. Lateral expansion of the wafer is... 

System test—turn off all modules and power-up to perform startup diagnostics. Perform static leak test of the pump and compression test of the autosampler as suggested by the manufacturer. 

One should constantly recall that a static stability test does not cover those effects likely to be associated with warehousing (in bulk), handling, transportation, display or use. It is essential that other tests cover these aspects to ensure that stability data is not invalidated. This may be done by the use of either laboratory simulated tests or actual field trials . Top pressure (compression) and/or vibration is likely to present one of the more serious hazards. 

Methods to determine compression behavior can be either static (dead load) or based on constantly increasing compression. Several methods for the determination of volume-reduction mechanisms due to compression or compaction have been presented in the literature the most relevant ones are described in the following sections. Compression mechanisms can be approached from different tests such as the Brazilian test, uniaxial confined compression test, cubical triaxial tester, HHP method, and the unconfined... 

Saint-Venant is famous for his principle in the strength of material that states that except in the immediate vicinity of the points of application of the load, the stress distribution may be assumed independent of the acmal mode of application of the load as long as loadings are statically equivalent. This principle is conveniendy used to find out the stresses far away from the load. In the immediate vicinity of the load, the stresses can be determined using advanced theoretical or experimental methods (Beer et al. 2004). Von Karman carried out compression test on marble under high pressure and results were published in 1911. 

A series of six different static tests were successfully passed by Glasshopper 1, including end compression, draft, vertical coupler-up, vertical coupler-down, coupler shank, and torsional jacking. The end compression test consisted of squeezing the car, while empty, with a hydraulic ram until a coupler force of 1,000,000 lb was measured. The draft test was conducted on the loaded car (105.9 tons) and consisted of pulling on the coupler until a force of 630,000 lb was experimentally observed. The remaining static tests were all conducted on the loaded car and involved using calibrated hydraulic rams to ... 

Shear modulus can be determined by a static torsion test or by a dynamic test using primarily a torsional pendulum (ASTM D 2236). Also used is an oscillatory rheometer test. The torsional pendulum is applicable to virtually all plastics and uses a simple specimen readily fabricated by all commercial fabricating processes or easily cut from fabricated part. The moduli of elasticity, G for shear and E for tension, are ratios of stress to strain as measured within the proportional limits of the material. Thus the modulus is really a measure of the rigidity for shear of a material or its stifihess in tension and compression. For shear or torsion, the modulus analogous to that for tension is called the shear modulus or the modulus of rigidity, or sometimes the transverse modulus. 

The compression properties characterize the strength, deformation and stiffness behaviour of plastics under quasi-static uniaxial compression load conditions. Generally, for these tests commercial universal test systems with different load capacity are used. The valid and common used standard for the compression test of plastics is the ISO 604 (2002) Plastics - Determination of compressive properties. The data collected include also values determined according DIN 53454 and DIN 53457 as well as ASTM D 695 (Fig. 4.33). The specimen of preference exhibits dimensions of 50 x 10x4 mm for the determination of modulus of elasticity and 10 x 10x4 mm for the investigation of the other compressive properties (Fig. 4.34). 

Static mechanical testing involves applying a constant stress or strain to a gel sample in tension or compression. 

EN 15416-2 2008, Adhesives for load bearing timber structures — Test methods — Part 2 Static load test of multiple bondfine specimens in compression shear. 

In addition to the above, the maximum permissible bitumen content is determined by executing the triaxial cyclic compression test according to CEN EN 12697 (2012), Method B, or the unconfined static creep test (see Section 7.6.3). This ensures sufficient resistance of the CAM to permanent deformation. 

Two specimens per bitumen content (use five levels of bitumen content), after curing for Marshall testing, are subjected to either the triaxial cyclic compression test or the static creep test at 40°C 0.5 C. 

The simplest test used to study the deformation behaviour of asphalts was the static unconfined uniaxial compression test, termed the creep test, developed in the 1970s by Shell Bitumen (Hill 1973). The specimen was subjected to static axial compressive load over a long period (1 h). The test procedure was very simple and required low-cost equipment. In addition. Shell Bitumen developed a rut prediction procedure based on results of the creep test but soon realised that it underestimated rut depths measured in trial pavements (Hill et al. 1974). This was attributed to the effects of dynamic loading producing higher deformation in the wheel-tracking test (Van de Loo 1974). 

The apparatus used is much simpler than the apparatus used in the cyclic compression test (Cabrera and Nikolaides 1987 Jongeneel et al. 1985). It is mentioned that the CRT-UTM-NU (Cooper Research Technology Ltd. 2014) apparatus is also capable of performing the static creep test. 

Figure 17.56 Illinois Institute of Technology Research Institute (IITRI) compression test. Source Reprinted from Hofer KE, Rao PN, A new static compression fixture for advanced composite materials, J. Test Eval5, 278-283, 1977.

Hofer KE, Rao PN, A new static compression fixture for advanced composite materials, J Testing... 

The first to be built was Glasshopper I. It successfiilly passed all of the required American Association of Railroads (AAR) tests including the 454.000 kg (1,000,000 lb) static end compression test and the 568.000 kg (1,250,000 lb) coupler force impact test in the laboratory, and then successfiilly completed a roimd trip between St. Louis, MO and Oakland, CA [9700 km (6000 mile)]. From outward appearance, the RP designs were very similar to the standard ACF steel-covered hopper car. The first RP prototype, Glasshopper 1 that was in grain service, had four compartments. The car had a total capacity of 142 m (5000 ft ) and an overall length of about 16 m (53 ft). Its basic specifications are shown in Table 6.1. Table 6.1 Glasshopper 1 basic specifications ... 

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