Determination of the parameters for design of flexible plastic tank

Abstract

The need to provide emergency water supplies in remote locations and to store water in small, irregular spaces was the main motivation for the research study. The flexible plastic tank provides a good solution to the challenges of efficient water supply to remote areas but has the disadvantage of creeping incessantly during use and does not recover its original dimensions after loading. This project sought to establish the limits within which the flexible HDPE tank may be used in hot tropical climates for water storage. The creep and recovery characteristics of the material were determined for the range of loads and temperatures at which the material is likely to be applied. A set of equations was developed from the creep and recovery curves to estimate the values of creep and recovery within the temperature range 30°C - 50°C and for stresses ranging from 0.781 to 1.563 MPa just by knowing only the applied stress and the operating temperature. Estimates were also provided for the expected permanent expansion of the material under load, when loaded once and when loaded and unloaded intermittently.