Inverse estimation of heat input in laser surface hardening with a dual-phase-lag model

This study deals with the application of the conjugate gradient method for estimating the unknown time-dependent heat input in laser surface hardening based on the dual-phase-lag model. Subsequently, inverse variations of temperature at the heated surface can be obtained. Simulated experimental data, needed for the inverse analysis, are generated by adding random errors to the calculated exact temperatures for the boundary and interior of the medium. Two examples are considered to illustrate the accuracy of the proposed method. The influence of the measurement error and the measurement location upon precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent laser heat input can be obtained with any arbitrary initial guess for the test cases considered in this study.