Blocking Load ASTM

Blocking Load (ASTM D3354) and Coefficient of Friction (ASTM D1894)... 

The standard blocking load test (ASTM D3354) utilizes two aluminum blocks with two layers of film pressed between them (Fig. 6.5). One film layer is attached to the upper block and the other layer to the lower block. The upper block is pulled away from the lower block with a small initial force that increases constantly over time. When a... 

While the blocking load test measures the force to separate the films perpendicular to their plane, a different method is used to measure the frictional forces required to slide one layer of film over another (ASTM D1894). In this test, a small sled drags one layer of film over another. A load cell measures the force required to initiate a sliding motion (related to the static coefficient of friction) and maintain a sliding motion (related to the kinetic coefficient of friction). 

ASTM D3354-11 Standard Test Method for Blocking Load of Plastic Film by the Parallel Plate... 

In ASTM D 3574 - Test F, tests are carried out using a power-driven apparatus which will indicate the final load at which rupture of a block-type test specimen takes place. An automatic machine may be used to draw the actual curve, or a style or scale may be used with an indicator that remains at the point of maximum force after rupture. The specimen is a block free of skin and densification lines. A 38-mm (1.5-in.) cut is made on one side of the specimen of dimensions 1.5 in. (38.1 mm) x 1 in. (25.4 mm) x 1 in. (25.4 nun). The results are reported in newtons per meter (N/m). This test is similar to BS 4443 Method 15. 

ASTM C 203-91 Standard Test Methods fox Breaking Load and Flexural Properties of Block-Type Thermal Insulation, 6 pp (DOD Adopted) (Comm C-16)... 

FIGURE 3.73 Tests for blocking of plastic film. Blocking force (Ibf/in. or kgf/cm ) = load (Ibf or kgf)/initial area of films in contact (in. or cm ). Standard test method ASTM D1893. 

Extrusion plastometer (melt-indexer) ru A simple viscometer consisting of a heated vertical cylinder with two bores, a central one that contains a close-fitting piston and a recess for an orifice block, the other, nearby, for a thermoswitch. The orifice is 2.1 nun in diameter and 8 mm long. Plastic particles are loaded into the bore, allowed to heat for 6-8 min, then the weighted piston is released, and the extrudate is collected for a measured time internal. The melt-flow index (MFI) is stated as the rate of extrusion in grams/10 min. The instrument and its use are described in ASTM D 1238. Originally developed in 1953 for low-density polyethylene, the melt-indexer is now used with many other polymers with specific temperatures and piston weights. It... 

Compression tests are carried out as per ASTM Cl65 and ASTM D1621 using the Instron 5569 Universal Testing Machine as shown in Fig. 5.3. Each GSA and GSA-SDS sample was cut into a square specimen of x y dimensions of 17.5 2.5 width 27.5 1.5 mm height (in z-direction) using razor blades. The blocks were compression tested in the z-direction at three strain rates, viz, 0.8/min, 1.2/min at the nominal strain up to 44.4 %, and at 1.0/min. Each specimen was loaded in compression using 500 N 4 % load cell with the initial load of 25 % of the nominal strain for 1 min and, thereafter was unloaded. The compressive modulus for each specimen is calculated with the in-built Instron Bluehill software. 

Another compressive shear test used for wood joints is ASTM D905-49. Test joints are prepared by bonding two blocks of wood, free from defects, with the grain of each block parallel to the length direction. Test specimens are cut from this bonded joint and tested in a special shearing apparatus (Figure 13). Loads are applied using a crosshead movement of 0.015 inch/min. The shear stress is calculated with the failure load and bonded shear area. 

Contrary to the long duration of fatigue and creep tests, impact tests occur in seconds. Samples can be made of wood or metal adherends and are block-shaped, as described in ASTM D950-82 (see Figure 18). Loading is administered by a pendulum arm which travels at a velocity of 11 ft/s. The arm shears off the top half of the block and the impact energy in foot-pounds per square inch of bond area is recorded. It should be noted that impact values are very sensitive to the adhesive layer thickness thicker layers will allow more deformation and an increase in energy absorption. 

ASTM E519 specifies a shear strength test in which a 1.2m masonry square is loaded across its diagonal. Cl 196 and C1197 are test methods for in situ compressive strength and deformability of masonry. The construction of dry-stacked surface bonded walls, in which walls of concrete blocks, laid close together without mortar are coated with mortar on both sides, is specified in ASTM C946. 

A plastic block is weight-loaded against the rim of the disk (line contact) and the wear test is usually between 20 and 30 hours. The plastic samples have dimensions that allow them to be made from plastic flex test bars that are commonly molded out of new plastics to measure their flexural properties. This test is intended to replace the thrust washer test. The ASTM test procedure does not require measurement of counterface wear, but it is always advisable to make this measurement. The disk weighs more than 3 kg, making it difficult to weigh it to measure mass change that occiured in a test Profilometry could be used. 

Table 10.16 Taber Abrasion of Arkema Pebax Polyether Block Amide Elastomers (ASTM D1044, HI8 Wheel, 1 kg Load)...

The basic principle on which this test, given by the ASTM D950 standard, relies is to apply an impact-loading condition, mainly in shear, by means of a test rig similar to that used for Izod resilience measurement. O Figure 21.1 shows the experimental arrangement. An upper block (usually of steel) is bonded onto another larger block which, in turn, is fixed to the base... 

Stress distribution on the adhesive mid-plane of the impact block ASTM 250 for different loading cases (a) shear stress (b) peel stress (From Adams and Harris [1996], copyright Elsevier)... 

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