A novel sound quality simulation approach was proposed to optimize the acoustic performance of a four-cylinder diesel engine.Finite element analysis,single-input and multiple-output technology,flexible multi-body dyna...A novel sound quality simulation approach was proposed to optimize the acoustic performance of a four-cylinder diesel engine.Finite element analysis,single-input and multiple-output technology,flexible multi-body dynamics,and boundary element codes were used to acquire the hexahedron-element model,experimental modal frequencies,vibration velocities,and structurally radiated noise of the block,respectively.The simulated modal frequencies and vibration velocities agreed well with the experimental data,which validated the finite-element block.The acoustic response showed that considerable acoustic power levels existed in 1500-1900 Hz and 2300-2800 Hz as the main frequency ranges to optimize the block acoustics.Then,the optimal block is determined in accordance with the novel approach,which reduces the overall value,high-frequency amplitudes,and peak values of acoustic power;thus,the loudness,sharpness,and roughness decline to make the sound quieter,lower-pitched,and smoother,respectively.Finally,the optimal block was cast and bench-tested.The results reveal that the sound quality of the optimal-block engine is substantially improved as numerically expected,which verifies the effectiveness of the research approach.展开更多
We have proposed a primal-dual fixed point algorithm （PDFP） for solving minimiza- tion of the sum of three convex separable functions, which involves a smooth function with Lipschitz continuous gradient, a linear co...We have proposed a primal-dual fixed point algorithm （PDFP） for solving minimiza- tion of the sum of three convex separable functions, which involves a smooth function with Lipschitz continuous gradient, a linear composite nonsmooth function, and a nonsmooth function. Compared with similar works, the parameters in PDFP are easier to choose and are allowed in a relatively larger range. We will extend PDFP to solve two kinds of separable multi-block minimization problems, arising in signal processing and imaging science. This work shows the flexibility of applying PDFP algorithm to multi-block prob- lems and illustrates how practical and fully splitting schemes can be derived, especially for parallel implementation of large scale problems. The connections and comparisons to the alternating direction method of multiplier （ADMM） are also present. We demonstrate how different algorithms can be obtained by splitting the problems in different ways through the classic example of sparsity regularized least square model with constraint. In particular, for a class of linearly constrained problems, which are of great interest in the context of multi-block ADMM, can be also solved by PDFP with a guarantee of convergence. Finally, some experiments are provided to illustrate the performance of several schemes derived by the PDFP algorithm.展开更多
文摘A novel sound quality simulation approach was proposed to optimize the acoustic performance of a four-cylinder diesel engine.Finite element analysis,single-input and multiple-output technology,flexible multi-body dynamics,and boundary element codes were used to acquire the hexahedron-element model,experimental modal frequencies,vibration velocities,and structurally radiated noise of the block,respectively.The simulated modal frequencies and vibration velocities agreed well with the experimental data,which validated the finite-element block.The acoustic response showed that considerable acoustic power levels existed in 1500-1900 Hz and 2300-2800 Hz as the main frequency ranges to optimize the block acoustics.Then,the optimal block is determined in accordance with the novel approach,which reduces the overall value,high-frequency amplitudes,and peak values of acoustic power;thus,the loudness,sharpness,and roughness decline to make the sound quieter,lower-pitched,and smoother,respectively.Finally,the optimal block was cast and bench-tested.The results reveal that the sound quality of the optimal-block engine is substantially improved as numerically expected,which verifies the effectiveness of the research approach.
文摘We have proposed a primal-dual fixed point algorithm （PDFP） for solving minimiza- tion of the sum of three convex separable functions, which involves a smooth function with Lipschitz continuous gradient, a linear composite nonsmooth function, and a nonsmooth function. Compared with similar works, the parameters in PDFP are easier to choose and are allowed in a relatively larger range. We will extend PDFP to solve two kinds of separable multi-block minimization problems, arising in signal processing and imaging science. This work shows the flexibility of applying PDFP algorithm to multi-block prob- lems and illustrates how practical and fully splitting schemes can be derived, especially for parallel implementation of large scale problems. The connections and comparisons to the alternating direction method of multiplier （ADMM） are also present. We demonstrate how different algorithms can be obtained by splitting the problems in different ways through the classic example of sparsity regularized least square model with constraint. In particular, for a class of linearly constrained problems, which are of great interest in the context of multi-block ADMM, can be also solved by PDFP with a guarantee of convergence. Finally, some experiments are provided to illustrate the performance of several schemes derived by the PDFP algorithm.
