Burst resistance

This approximately 10% increase in the MAOP permits an increase in working gas capacity of approximately 15%. Considering the extra investment linked to MAOP increases (e.g. increases compression ratio and bursting resistance), savings are between 12 and 14%. 

E-beam crosslinking does provide some advantages over chemical aosslinking agents, however. In extruded pipe, researchers have found that radiation-crosslinked PE has equal or better burst resistance at high temperatures than... 

Orientation of polymer molecules in the wall of pipes can be used to add strength in the more highly stressed directions. Burst resistance can be increased by peripheral orientation (hoop direction) and tensile loading resistance in the axial direction can be increased by orientation parallel to the direction of extrusion. The combination of these is beneficial for many pipe applications and is referred to as biaxial orientation. This was recognised relatively early in the development of PE pipe extrusion technology and Hoechst the PE supply company worked with the extruder manufacturer Rieffenhauser on methods of creating biaxial orientation in [59]. 

Chemical protective clothing (requirements for fabric materials was defined in EN EN 14605 2005 Protective clothing against liquid chemicals Performance requirements (type 3 and 4 PB[3] and PB[4]) BS EN ISO 12947-2 1998 EN ISO 7854, method B, EN ISO 7854, method B at -30°C EN ISO 9073 EN ISO 13938-1 Abrasion resistance Flex cracking resistance Flex cracking resistance at —30°C Tear resistance (trapezoidal) Bursting resistance... 

The useful life of a fabric depends on a number of factors, including the strength, stretch, recovery, toughness, and abrasion resistance of the fiber and the tearing and bursting resistance of the fabrics made from that fiber. The composite of these factors coupled with the conditions and type of end-use or wear will determine the durability characteristics of a textile structure made from the fiber. 

Relevant duration Tensile properties Creep behaviour Puncture and bursting resistance 1 month Important Insignificant Very important 3 months to 5 years Important Important Possible influence >3 years Important Very important Possible influence... 

Before an analytical calculation or laboratory test is conducted, the possible failure modes of the part should be thoroughly reviewed. The most vulnerable failure mode will determine the test method. Few mechanical parts fail due to static load such as tensile stress. ITowever, the tensile stress plays a critical role in disk burst resistance under high-speed rotation. Tensile strength also represents a generic mechanical strength on many occasions. To conduct a tensile test and use the material s tensile properties to substantiate the equivalent performance of a reverse engineered part is usually acceptable as a first comparison. Other mechanical tests are also frequently required for critical parts and different failure modes. 

Tables 4—6 Ust ASTM methods used for the characterization of PB and PMP. A number of specialized methods were developed for testing particular articles manufactured from polyolefins several of these determine the performance of PB and PMP film, including the measurement of the film s dart impact strength and tear strength. Dart impact strength is measured by dropping a heavy dart with a round tip on a stretched film. Tear resistance, which reflects the film s resistance to tear propagation, is measured with the Ehnendorf tear tester. Two values for the tear strength are usually reported, one in the machine dkection of the film and the other in the transverse dkection. Pipes manufactured from PB are tested by pressurizing them internally with water the time-to-burst failure is determined at various temperatures (46). The standard test method for haze and luminous transmittance (ASTM D1003) is used for the measurement of PMP optical characteristics.

Starches used to increase the internal strength of paper as measured by tensile, edge cmsh resistance, Mullen burst, and Scott bond strength are added at the wet end, whereas starch used to increase surface strength as measured by pick and resistance to Hnting are added at the size press. 

Master curves can be used to predict creep resistance, embrittlement, and other property changes over time at a given temperature, or the time it takes for the modulus or some other parameter to reach a critical value. For example, a mbber hose may burst or crack if its modulus exceeds a certain level, or an elastomeric mount may fail if creep is excessive. The time it takes to reach the critical value at a given temperature can be deduced from the master curve. Frequency-based master curves can be used to predict impact behavior or the damping abiUty of materials being considered for sound or vibration deadening. The theory, constmction, and use of master curves have been discussed (145,242,271,277,278,299,300). 

Resistance to Fracture - The ion or ionized complexes that the resins are required to fix are of varied dimensions and weights. The swelling and contraction of the resin bead that this causes must obviously not cause the grains to burst. 

These are thin diaphragms held between flanges and calibrated to burst at a specified static inlet pressure. Unlike relief valves, rupture discs cannot reseal when the pressure declines. Once the disc ruptures, any flow into the vessel will exit through the disc, and the disc must be replaced before the pressure vessel can be placed back in service. Rupture discs are manufactured in a variety of materials and with various coatings for concision resistance. 

First and foremost these venting ducts should be as straight as possible, with few, if any elbows, and even these should be sw eeping bends. There should be no valves of any type to keep flow resistance as low as possible, as this creates friction that creates backpressure on the relief de ice and raises burst conditions, which can be terribly dangerous. Figure 7-66 and 7-67 are used to assess the increased pressure due to ducts on relief discharge as affected by duct length. (This data is limited. See Ref. [56 and 53].)... 

Casing must be designed to resist expected burst pressure at any depth. In burst pressure consideration, it is suggested to consider different design models depending upon the type of casing string. 

Steel grade Unit weight (Ib/ft) Cross-sectional sraa (In.) Collapse pressure resistance Burst pressure resistance Joint strength (10> lb) Pipe body strength (10> lb)... 

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