Eliete Pereira - LEPTEN - Universidade Federal de Santa Catarina

xviABSTRACTThis work analysis theoretically and experimentally (using experimental data obtainedfrom the literature), the contact pressure distribution in bolted metal joints, besides studyingthe thermal contact conductance of such joints.It is known that when two plates are put in contact, this contact is not perfect andwhen these are bolted the screw causes the contact pressure distribution between theplates, and this, in real situations, is not uniform.Three different configurations were used for the bolted joints: the first one iscomposed of two aluminum discs, the second has two stainless steel discs and the last iscomposed of one aluminum disc and the other of stainless steel. The discs are boltedthrough a hole in the middle. Two screws with different bolt head radius are tested. Thecontact conductance tests were all done in a void space.For each bolted joint were applied five different axial loads. Each bolted joint testedpresented a different behaviour among them, as in relation to contact pressure distribution asto contact thermal conductance.There was comparison between some existent models and experimental data ofcontact pressure distribution, being that these did not obtain a good concordance amongthemselves. It was proposed a correlation for such distribution based on the Weibulldistribution, since it has a broad use in areas that goes from biological science to mechanicalengineering.Using contact thermal conductance models from the literature, it was calculated theconductance for several bolted joints based on the Weibull pressure distribution. Thetheoretical values generally do not agree with the experimental data of contact thermalconductance. It is believed that it is due to the fact that the models were developed forcontact uniform pressure. In the case of bolted joints this does not happen. Moreover, it isbelieved that the surface flatness deviations also contribute for the non-uniformity contactpressure.