The minimal error method for the Cauchy problem in linear elasticity. Numerical implementation for two-dimensional homogeneous isotropic linear elasticity

AbstractIn this paper, yet another iterative procedure, namely the minimal error method (MEM), for solving stably the Cauchy problem in linear elasticity is introduced and investigated. Furthermore, this method is compared with another two iterative algorithms, i.e. the conjugate gradient (CGM) and Landweber–Fridman methods (LFM), previously proposed by Marin et al. [Marin, L., Háo, D.N., Lesnic, D., 2002b. Conjugate gradient-boundary element method for the Cauchy problem in elasticity. Quarterly Journal of Mechanics and Applied Mathematics 55, 227–247] and Marin and Lesnic [Marin, L., Lesnic, D., 2005. Boundary element-Landweber method for the Cauchy problem in linear elasticity. IMA Journal of Applied Mathematics 18, 817–825], respectively, in the case of two-dimensional homogeneous isotropic linear elasticity. The inverse problem analysed in this paper is regularized by providing an efficient stopping criterion that ceases the iterative process in order to retrieve stable numerical solutions. The numerical implementation of the aforementioned iterative algorithms is realized by employing the boundary element method (BEM) for two-dimensional homogeneous isotropic linear elastic materials

The method of fundamental solutions for nonlinear functionally graded materials

AbstractIn this paper, we investigate the application of the method of fundamental solutions (MFS) to two-dimensional steady-state heat conduction problems for both isotropic and anisotropic, single and composite (bi-materials), nonlinear functionally graded materials (FGMs). In the composite case, the interface continuity conditions are approximated in the same manner as the boundary conditions. The method is tested on several examples and its relative merits and disadvantages are discussed

Regularized MFS solution of inverse boundary value problems in three-dimensional steady-state linear thermoelasticity

We investigate the numerical reconstruction of the missing thermal and mechanical boundary conditions on an inaccessible part of the boundary in the case of three-dimensional linear isotropic thermoelastic materials from the knowledge of over-prescribed noisy data on the remaining accessible boundary. We employ the method of fundamental solutions (MFS) and several singular value decomposition (SVD)-based regularization methods, e.g. the Tikhonov regularization method (Tikhonov and Arsenin, 1986), the damped SVD and the truncated SVD (Hansen, 1998), whilst the regularization parameter is selected according to the discrepancy principle (Morozov, 1966), generalized cross-validation criterion (Golub et al., 1979) and Hansen's L-curve method (Hansen and O'Leary, 1993)

Modelling and operational testing of pulse-width modulation at injection time for a spark-ignition engine

Danas, kada govorimo o bilo kojem polju moramo uključiti upravljanje računalom. Zbog prednosti njegovog binarnog sustava, ono može upravljati signalima iz uređaja i kontrolirati ih u vrlo kratkom vremenu. U ovom radu smo željeli predstaviti studije i istraživanja tehnologije PWM (Pulse Width Modulation - modulacije širine impulsa). Današnji motori su opskrbljeni s elektronički upravljanim sustavom ubrizgavanja. Tijekom istraživanja uspostavili smo vezu između nekoliko parametara koji su uključeni u povećanje performansi motora. PWM, najčešće korištena tehnika za kontroliranje snage inercijskih električnih uređaja, korištena je za predstavljanje prednosti kontrole vremena ubrizgavanja, s vrlo dobrim rezultatima u sustavu upravljanja motorom. Uzeli smo u obzir neke parametre, kao tlak, napon baterije, lambda signale, količinu goriva i zraka, itd., a sve to u vremenskom razvoju s ECU pomoćnim upravljanjem. Korištenje MATLAB/Simulink softvera uspjeli smo upravljati, počevši od referentnih brzina, položaja regulacije i drugih parametara, potrebnih podataka iz ispitivanog vozila, Dacia Logan 1.4 MPI (pokretanog Renaultom), razvojem vremena ubrizgavanja uporabom modulacije širine impulsa. Stvaranjem PWM signala možemo točno kontrolirati vrijeme ubrizgavanja.Nowadays, the computer control has to be taken into account in any field of study. Due to the advantage of its binary system, it can very quickly control the signals from devices. This paper is focused on the analysis of some studies carried out on the PWM (Pulse Width Modulation) technologies. The engines used nowadays are provided with an electronic injection system. During our research, we have made a connection between a few parameters which contribute to the increase of the engine performance. Our team has used the PWM, a common technique employed for controlling power to inertial electrical devices, in order to show the benefits of the injection time control; the results regarding the engine management have been very good. We have taken into account a few parameters such as pressure, battery voltage, lambda signals, fuel and air amount, etc., as well as their time evolution, with the help of the ECU control. Using the MATLAB/Simulink software, we have managed to control, by using the pulse width modulation, the reference speed, the throttle position, as well as other parameters and data collected from the tests carried out on Dacia Logan 1.4 MPI (powered by Renault), and the evolution of the injection time. By creating a PWM signal, we can precisely control the injection time

Modelling and operational testing of pulse-width modulation at injection time for a spark-ignition engine

Danas, kada govorimo o bilo kojem polju moramo uključiti upravljanje računalom. Zbog prednosti njegovog binarnog sustava, ono može upravljati signalima iz uređaja i kontrolirati ih u vrlo kratkom vremenu. U ovom radu smo željeli predstaviti studije i istraživanja tehnologije PWM (Pulse Width Modulation - modulacije širine impulsa). Današnji motori su opskrbljeni s elektronički upravljanim sustavom ubrizgavanja. Tijekom istraživanja uspostavili smo vezu između nekoliko parametara koji su uključeni u povećanje performansi motora. PWM, najčešće korištena tehnika za kontroliranje snage inercijskih električnih uređaja, korištena je za predstavljanje prednosti kontrole vremena ubrizgavanja, s vrlo dobrim rezultatima u sustavu upravljanja motorom. Uzeli smo u obzir neke parametre, kao tlak, napon baterije, lambda signale, količinu goriva i zraka, itd., a sve to u vremenskom razvoju s ECU pomoćnim upravljanjem. Korištenje MATLAB/Simulink softvera uspjeli smo upravljati, počevši od referentnih brzina, položaja regulacije i drugih parametara, potrebnih podataka iz ispitivanog vozila, Dacia Logan 1.4 MPI (pokretanog Renaultom), razvojem vremena ubrizgavanja uporabom modulacije širine impulsa. Stvaranjem PWM signala možemo točno kontrolirati vrijeme ubrizgavanja.Nowadays, the computer control has to be taken into account in any field of study. Due to the advantage of its binary system, it can very quickly control the signals from devices. This paper is focused on the analysis of some studies carried out on the PWM (Pulse Width Modulation) technologies. The engines used nowadays are provided with an electronic injection system. During our research, we have made a connection between a few parameters which contribute to the increase of the engine performance. Our team has used the PWM, a common technique employed for controlling power to inertial electrical devices, in order to show the benefits of the injection time control; the results regarding the engine management have been very good. We have taken into account a few parameters such as pressure, battery voltage, lambda signals, fuel and air amount, etc., as well as their time evolution, with the help of the ECU control. Using the MATLAB/Simulink software, we have managed to control, by using the pulse width modulation, the reference speed, the throttle position, as well as other parameters and data collected from the tests carried out on Dacia Logan 1.4 MPI (powered by Renault), and the evolution of the injection time. By creating a PWM signal, we can precisely control the injection time