共查询到9条相似文献，搜索用时 0 毫秒
1.
Alexander Tesar 《International journal for numerical methods in engineering》2004,60(11):1791-1801
Research of the ultimate behaviour of the carbon fibre composites is treated in the present paper. The material instability on the basis of the fibre kinking theory is adopted for the treatment of the failure process in the problem. The micromechanical modelling adopting the FETM‐wave approach is used for the numerical analysis of the problem. Some numerical and experimental results obtained are submitted in order to demonstrate the efficiency of the procedures suggested. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
Alexander Tesar 《International journal for numerical methods in engineering》1999,45(9):1243-1255
In many cases slender structures are lightly damped, a condition described as ‘lively’, and can undergo large vibrations when subjected to traffic or environmental forcing. One measure against above vibrations is the application of tuned vibration control facilities in structures. The fibre members with variable prestressing forces and tuning facilities are adopted for the purpose of tuned vibration control of structures below. Theoretical backgrounds of present approaches as well as numerical and experimental studies of tuned vibration control problems in slender structures of guyed masts are submitted below. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
3.
Alexander Tesar Marek Sedlar 《International journal for numerical methods in engineering》2006,67(9):1193-1203
Numerical and experimental assessment of a new connecting strip for the behaviour control of modern composite structures is treated in the present paper. The wave approach of the back‐propagation neural network in micromechanical modelling is used for the numerical analysis of the problem. Some numerical and experimental results are submitted in order to demonstrate the efficiency of the connecting strip developed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
4.
Alexander Tesar Marek Sedlar 《International journal for numerical methods in engineering》2004,61(14):2389-2401
Numerical and experimental assessment of modern composite structures provided with knowledge‐based joints for their behaviour control is treated in the present paper. Special connection strip, joining composite materials, is adopted. The wave approach of the back propagation neural network in micro‐ and macromechanical modelling is used for the numerical analysis of the problem. Some numerical and experimental results are given in order to demonstrate the efficiency of the control joint suggested. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
5.
Alberto Carpinteri Francesco Montagnoli Stefano Invernizzi 《Fatigue & Fracture of Engineering Materials & Structures》2020,43(8):1869-1879
The present contribution investigates size effects on Wöhler's curve in accordance with dimensional analysis and intermediate asymptotics theory. These approaches provide a generalised equation able to interpret the specimen‐size effects on Wöhler's curve. Subsequently, using a different approach based on lacunar fractality concepts, analogous scaling laws are found for the coordinates of the limit‐points of Wöhler's curve, so that a theoretical explanation is provided to the decrement in fatigue resistance by increasing the specimen size. Eventually, the proposed models are compared with experimental data available in the Literature, which seem to confirm the advantage of applying fractal geometry to the problem. 相似文献
6.
Alexander Tesar 《International journal for numerical methods in engineering》2006,68(7):790-807
Bionics and fractal configurations mapping the schemes from the nature and adopted in present structural engineering are dealt with in present paper. Theoretical and numerical assessments of such configurations are based on the wave approaches running in neural network models corresponding with the genetic algorithms also appearing in nature. Generalized ultimate behaviour of such configurations and structures is analysed. Some structural applications based on such principles are presented. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
7.
Fatigue life assessments of parts are frequently undertaken using the nominal stress concept. The main element in the process is the linear damage accumulation concept according Palmgren and Miner. Statistical analyses show the calculated fatigue life to commonly be on the unsafe side and the accuracy to be low. A higher accuracy would be advantageous, as the present use of effective damage sums is only an adaption. Improvements of the original Palmgren‐Miner rule made use of in practical calculations have mainly been achieved by taking into account amplitudes below the fatigue limit as further damage. The method described in the following utilises a different approach. The influence of the spectrum shape and the inclination of the S‐N curve under constant amplitude loading on the progression of the S‐N curve under variable amplitude loading, easily made visible in statistical comparisons of calculated and experimental fatigue lives, shall be included in a new correction function. The verification of the improvement of the fatigue life estimation can be undertaken using existing experimental data of steel specimens. Furthermore calculations are carried out to find optimized parameters of two Palmgren‐Miner modifications (Haibach, Liu/Zenner). 相似文献
8.
This study presents a model for estimating the fatigue life of magnesium and aluminium non‐penetrated butt‐welded joints using Artificial Neural Network (ANN). The input parameters for the network are stress concentration factor Kt and nominal stress amplitude sa,n. The output parameter is the endurable number of load cycles N. Fatigue data were collected from the literature from three different sources. The experimental tests, on which the fatigue data are based, were carried out at the Fraunhofer Institute for Structural Durability and System Reliability (LBF), Darmstadt – Germany. The results determined with use of artificial neural network for welded magnesium and aluminium joints are displayed in the same scatter bands of SN‐lines. It is observed that the trained results are in good agreement with the tested data and artificial neural network is applicable for estimating the SN‐lines for non‐penetrated welded magnesium and aluminium joints under cyclic loading. 相似文献
9.
J. Gegner 《Materialwissenschaft und Werkstofftechnik》2006,37(3):249-259
Material Response Analysis and its Application to Rig Tests for the Surface Failure (Nierlich Damage Mode) of Rolling Bearings The material response analysis according to Nierlich using X‐ray diffraction represents an important physical examination technique for the evaluation of material stressing and the lifetime estimation of rolling bearings and other highly loaded machine parts. The method is presented and employed for the evaluation of automobile gearbox rig tests. The extensively described damage modes of the practically predominating surface and the classical sub‐surface failure of rolling bearings can be distinguished that way. In gearboxes, lubricating oil contaminated by metal abrasion of the cogwheels usually appears. Penetrating foreign particles produce indentations at the ring raceways and rolling elements of the rolling bearings, which promotes surface fatigue. The results of the X‐ray diffraction measurements confirm this damage mode. Evaluation of the occurred material stressing permits a more detailed characterization of the surface failure of rolling bearings. 相似文献