Pressure-induced stress

Zheng, R. Kennedy, P. Phan-Thien, N. Fan, X.J. Thermoviscoelastic simulation of thermally and pressure induced stresses in injection molding. J. Non-Newtonian Fluid Mech. 1999, 84, 159-190. 

The majority of process plant pipelines operate at moderate pressures, say less than 10 bar. Consequently, as can be verified by simple hoop-stress calculations, for steel pipes the pressure-induced stresses are fairly nominal in relation to the material strength, and it is not necessary to increase the thickness much as pipe diameters increase. Pipe wall thickness is selected to provide adequate corrosion allowance and mechanical strength and rigidity, particularly in bending. This is not the case for plastic pipes, where more care must be taken to avoid pressure-induced failure, and it becomes more important to understand system characteristics by which over-pressure may arise. 

R. Zheng et. al., Thermo viscoelastic Simulation of Thermally and Pressure Induced Stresses in Injection Moulding for the Prediction of Shrinkage and Warpage for... 

Thermally and Pressure-Induced Stresses 6.3.1 Stress Development... 

Fig. 6.4 Thermally and pressure-induced stress (

In the calculation of the thermally and pressure-induced stresses, the material behavior can be described by either a viscous-elastic model (see, for example, Titomanlio et al. 1987 Jansen 1994 Boitout et al. 1995) or a viscoelastic model... 

For thin-walled injection-molded parts, the calculation of thermally and pressure-induced stresses can be simplified considerably by using the thin-film approximation. This enables us to apply the following assumptions ... 

Here the single term cr°. replaces (4 Cyki ) in Eq. 6.59. If Eq. 6.60 is to be used, the calculation procedure for the in-mold thermally and pressure-induced stress has to be continued to the room temperature. If the material has fully frozen... 

While there are a number of important dimensional analyses that may be made for the IC engine, the following one for inertia- and pressure-induced stresses is representative. Here, we assume that components of stress due to weight are negligible compared with inertia-induced components of stress. The pertinent variables forlhis problem are listed in Table 11.2. 

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