Evaluation of uncertainty of measurement for cellulosic fiber and isotactic polypropylene composites subjected to tensile testing
There is evident effort shown by the global scientific community towards experimental investigation and characterization of cellulosic fibers geared towards optimizing cellulosic fibers for composite processing. Areas of attention include fiber chemical pre-treatment, composite architectural considerations such as the fiber loading effects and matrix hydrophilicity, amongst the others. On one hand, there has not been much exploration geared towards assessment and ascertainment of the effects and influence of test systems and environmental conditions particularly to mechanical testing with regard to conveying the quality of results. This research seeks to outline specific factors with adverse contribution to the results for cellulosic-fiber composites based on tensile test. By virtue of the tensile test’s inherent similarity in configuration to stress relaxation and creep test, the methodology of quantification of doubt which exists about this test could also be applied to the latter two based on that the two tests are a paramount criteria for cellulosic fiber composites’ long term performance characterization. Factors contributing to uncertainty of measurement have been identified and their respective effect quantified. This is in a bid to convey the quality of results and outline laboratory environmental elements to critically control and monitor in order to achieve authentic results. Relative humidity and temperature were observed to be the main contributors to uncertainty of measurement at 96.32% and 3.25 % correspondingly. The resulting expanded uncertainty exhibited levels in the margins of 20 %, which cautions for critical control of the environment and the testing system if consistently accurate results are to be assured.
Keywords: Uncertainty of measurement, tensile, cellulosic fiber composite, mercerization, sisal fiber