https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Sun, 12 Apr 2026 19:31:22 GMT 2026-04-12T19:31:22Z http://hdl.handle.net/10985/7479 LSE method using the CHSS model LANTIERI, Pascal; GUERIN, Fabrice; VOICULESCU, Sorin Testing the reliability at a nominal stress level may lead to extensive test time. Estimations of reliability parameters can be obtained faster thanks to step-stress accelerated life tests (ALT). Usually, a transfer functional defined among a given class of parametric functions is required, but Bagdonavičius and Nikulin showed that ALT tests are still possible without any assumption about this functional. When shape and scale parameters of the lifetime distribution change with the stress level, they suggested an ALT method using a model called CHanging Shape and Scale (CHSS). They estimated the lifetime parameters at the nominal stress with maximum likelihood estimation (MLE). However, this method usually requires an initialization of lifetime parameters, which may be difficult when no similar product has been tested before. This paper aims to face this issue by using an iterating least square estimation (LSE) method. It will enable one to initialize the optimization required to carry out the MLE and it will give estimations that can sometimes be better than those given by MLE. Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/10985/7479 2009-01-01T00:00:00Z LANTIERI, Pascal GUERIN, Fabrice VOICULESCU, Sorin Testing the reliability at a nominal stress level may lead to extensive test time. Estimations of reliability parameters can be obtained faster thanks to step-stress accelerated life tests (ALT). Usually, a transfer functional defined among a given class of parametric functions is required, but Bagdonavičius and Nikulin showed that ALT tests are still possible without any assumption about this functional. When shape and scale parameters of the lifetime distribution change with the stress level, they suggested an ALT method using a model called CHanging Shape and Scale (CHSS). They estimated the lifetime parameters at the nominal stress with maximum likelihood estimation (MLE). However, this method usually requires an initialization of lifetime parameters, which may be difficult when no similar product has been tested before. This paper aims to face this issue by using an iterating least square estimation (LSE) method. It will enable one to initialize the optimization required to carry out the MLE and it will give estimations that can sometimes be better than those given by MLE. http://hdl.handle.net/10985/7481 Reliability Estimation by ALT when no Analytical Model Holds LANTIERI, Pascal; GUERIN, Fabrice; HAMBLIA, Ridha This paper presents an accelerated life testing method applicable to devices or systems when no analytical relationship with respect to the stress level can be defined. If a numerical approach remains possible, the numerical model can be fitted to the accelerated test results. Thus, long-term failures can be predicted from short tests. This method is carried out in the case of fatigue, the evolution of the damage leading to the failure having to be modeled by a numerical finite element method. Fri, 01 Jan 2010 00:00:00 GMT http://hdl.handle.net/10985/7481 2010-01-01T00:00:00Z LANTIERI, Pascal GUERIN, Fabrice HAMBLIA, Ridha This paper presents an accelerated life testing method applicable to devices or systems when no analytical relationship with respect to the stress level can be defined. If a numerical approach remains possible, the numerical model can be fitted to the accelerated test results. Thus, long-term failures can be predicted from short tests. This method is carried out in the case of fatigue, the evolution of the damage leading to the failure having to be modeled by a numerical finite element method.