Fatigue failure has long been an important issue for ships and offshore structures. Among the numerous methods for predicting fatigue life, the spectral method is accepted as the most reliable. Although the theory beh...Fatigue failure has long been an important issue for ships and offshore structures. Among the numerous methods for predicting fatigue life, the spectral method is accepted as the most reliable. Although the theory behind spectral analysis is straight-forward, the analysis itself is complicated and time-consuming because it is closely related to critical technical details such as the application of fatigue loading (wave pressures and the inertial forces due to cargoes), the extraction of the stress, and the calculation of stress RAO. Here, four key technical details-loading application, displacement boundary condition, the calculation of stress RAO, and the extraction of the fatigue stress-are discussed thoroughly. For each aspect, a resolution is presented based on the finite element pre-and post-processing software MSC/PATRAN or FE solver MSC/NASTRAN. The resolutions are effective and efficient, which can help engineers perform spectral fatigue analysis accurately and faster.展开更多
With determination micro-Fe by 1, 10-phenanthroline spectrophotometry for example, they are systematically introduced the combinatorial measurement and regression analysis method application about metheodic principle,...With determination micro-Fe by 1, 10-phenanthroline spectrophotometry for example, they are systematically introduced the combinatorial measurement and regression analysis method application about metheodic principle, operation step and data processing in the instrumental analysis, including: calibration curve best linear equation is set up, measurand best linear equation is set up, and calculation of best value of a concentration. The results showed that mean of thrice determination , s = 0 μg/mL, RSD = 0. Results of preliminary application are simply introduced in the basic instrumental analysis for atomic absorption spectrophotometry, ion-selective electrodes, coulometry and polarographic analysis and are contrasted to results of normal measurements.展开更多
文摘Fatigue failure has long been an important issue for ships and offshore structures. Among the numerous methods for predicting fatigue life, the spectral method is accepted as the most reliable. Although the theory behind spectral analysis is straight-forward, the analysis itself is complicated and time-consuming because it is closely related to critical technical details such as the application of fatigue loading (wave pressures and the inertial forces due to cargoes), the extraction of the stress, and the calculation of stress RAO. Here, four key technical details-loading application, displacement boundary condition, the calculation of stress RAO, and the extraction of the fatigue stress-are discussed thoroughly. For each aspect, a resolution is presented based on the finite element pre-and post-processing software MSC/PATRAN or FE solver MSC/NASTRAN. The resolutions are effective and efficient, which can help engineers perform spectral fatigue analysis accurately and faster.
文摘With determination micro-Fe by 1, 10-phenanthroline spectrophotometry for example, they are systematically introduced the combinatorial measurement and regression analysis method application about metheodic principle, operation step and data processing in the instrumental analysis, including: calibration curve best linear equation is set up, measurand best linear equation is set up, and calculation of best value of a concentration. The results showed that mean of thrice determination , s = 0 μg/mL, RSD = 0. Results of preliminary application are simply introduced in the basic instrumental analysis for atomic absorption spectrophotometry, ion-selective electrodes, coulometry and polarographic analysis and are contrasted to results of normal measurements.
