Burst pressure tests

The fracture strength of polysilicon layers can be measured by burst pressure testing of membranes or by using sophisticated surface-micromachined tensile test structures based on, for example, selective ion implantation [28], an electrostatic force grip [29], or a micromanipulator [14]. The fracture strength determined by the different techniques varies significantly with the different measurement principles. However, several conclusions can be drawn from published tensile testing experiments ... 

Apart from stiffness determination, other mechanical characterizations are required to quafify vascular grafts, including suture-retention strength and burst pressure testing. The suture-retention strength test aims at determining the force necessary to pull a... 

The burst pressure test characterizes the maximum internal pressnre, the vascnlar graft resists before failnre. The bnrst test is carried ont in the hydrated state nsing a setup similar to that of the pressure-diameter test that allows the system to achieve pressures higher than the physiological range (>2000 mm Hg). 

Prototype composite vessels (Fig. 12) were manufactured in the conditions used in the FEM simulations using a 6-axes CNC controlled filament winding machine and submitted to hydraulic burst pressure tests. The obtained results have shown that vessel burst occurred for pressures between 8 and 11 MPa. Such results show that conservative results were obtained from FEM analysis probably because failure does not occur by interlaminar shear as other simplified theories, like the netting one, demonstrate. 

The defect was detected and located during the proof test, and acoustic emission could follow its evolution until 20 bars during the burst test. After the pressure, the evolution of defect stopped till the burst. This test confirm the capability of acoustic emission to detect the evolution of defect during a pneumatic test with a sufficiently wide margin relative to the burst pressure. 

Plots of the bursting pressures of the Ni—Cr—Mo cylinders (EN 25) vs k derived from equations 16 and 17 show that neither equation is in such good agreement with the experimental results as is the curve derived from Manning s theory. Similar conclusions have been reached for cylinders made of other materials which have been tested (16). Manning s analytical procedure may be programmed for computation and, although torsion tests are not as commonly specified as tension tests, they are not difficult or expensive to carry out (20). 

A difference between tank cars and most pressure vessels is that tank cars are designed in terms of the theoretical ultimate or bursting strength of the tank. The test pressure is usually 40 percent of the bursting pressure (sometimes less). The safety valves are set at 75 percent of the test pressure. Thus, the maximum operating pressure is usually 30 percent of the bursting pressure. This gives a nominal factor of safety of 3.3, compared with 4.0 for Division 1 of the ASME Pressure Vessel Code. 

Brittle fracture is probably the most insidious type of pressure-vessel failure. Without brittle fracture, a pressure vessel could be pressurized approximately to its ultimate strength before failure. With brittle behavior some vessels have failed well below their design pressures (which are about 25 percent of the theoretical bursting pressures). In order to reduce the possibility of brittle behavior. Division 2 and Sec. Ill require impac t tests. 

A workman, pressure testing pipe work with a hand-operated hydraulic pump, told his foreman ih.n he could i ]( ct llic uauuc reading above 200 psi. The foreman told him to pump harder. He did so bursting the pipeline Hie uiue wus calibrated in atmospheres and not psi. The abbreviation "atm." in small letters was not under,in nl... 

Berstdnick, m. bursting pressure, bersten, v.t. burst, explode, rupture, crack. Berstprobe,/. (Paper) burst(ing) test. 

After the disk has been manufactured and tested, it is stamped with the rated burst pressure. The rated (stamped) burst pressure is established by bursting a minimum of two disks and averaging the pressures at which the disks burst. This average is the rated (stamped) burst pressure of the disk. Standard rupture disks above 15 psig 72°F are provided with a burst tolerance of 5% of the rated (stamped) burst pressure. This is in accordance with the ASME code. Burst tolerances for disks below 15 psig 72°F are oudined in Table 7-2. Burst tolerance applies only to the rated (stamped) burst pressure of the disk. Burst certificates are provided with each disk lot. 

The Code requires that the disks be burst on test by one of three methods using four sample disks, but not less than 5% from each lot. Figure 7-32 illustrates test results for burst pressure versus temperature of a disk design, all fabricated from the same material, and of the same diameter. 

As allowed by code [1], the average of the manufacturer s disks burst tests could be stamped, for example, (144 + 160.5)/2 = 152.3 psig with an actual 5% of 152.3 psig allowed for actual burst pressure of any disk at the operating temperature. 

Worst-case analysis based on the DSC data, namely, the test with the lowest onset temperature, resulted in a graph showing the relationship between initial temperature and time-to-maximum rate under adiabatic conditions. For an initial temperature of 170°C, it would take 2 hours to reach the maximum rate. Venting simulation tests were undertaken on a larger scale to detect safe venting requirements for the separator and for the MNB hold tank. Several vent sizes were tested. It was found that a 10-cm rupture disc with a burst pressure 1 bar above the operating pressure was adequate. 

At 1900 (almost seven hours after administration) he was still confused. He thought he heard girls voices and wondered who they were simultaneously he became more negativistic, flatly refusing to submit to blood pressure tests. He explained that he felt he was being pumped up and might very well burst ( either the machine would go up or I would. ). 

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