Papers by Author: Mahfodzah M. Padzi

Abstract: This research discussed on the determination of the appropriate fatigue damage parameter to predict the fatigue life when material subjected to the biaxial loading condition with the consideration of the energy dissipated. Servo-hydraulic machine is used for the constant amplitude cyclic testing on smooth solid mild steel. The results showed that in the low cycle fatigue, the total strain energy density can represent the accumulative of fatigue damage and characterize on the damage parameters. The relationship has been proposed which the data satisfactorily correlated for the R² is 0.8656. In addition, the hysteresis loop represent the area under the graph was the energy stored in the material during the loading and unloading condition. Hence the circumstances showed the deformation process governing the nucleation and propagation of fatigue cracks associated with the energy dissipated.

Abstract: This paper describes the correlation between fatigue life with the I-kaz coefficients. Fatigue tests were performed according to the ASTM E466-96 standard with a strain gauge attached to the specimen being tested. AISI 1045 carbon steel was used as the material for this test due to its wide applications in the automotive and machinery industry. Fatigue tests were carried out at several constant loading stresses of 610 MPa, 650 MPa and 690 MPa at the sampling frequency of 8 Hz. A set of data acquisition system was used to collect the fatigue strain signals. The integrated Kurtosis-based algorithm for Z-filter (I-kaz) technique had been used to find the I-kaz coefficient. The I-kaz coefficient is found to have a good correlation with fatigue life, other than can represent fatigue damage.

Abstract: This paper is aimed to investigate the fatigue assessment of aluminium alloy 6061specimen, one of the widely used aluminium alloys in the production of mechanical components. The alloy possesses the ability of critical failure caused by fatigue when they are subjected to dynamic responses in automotive-type components. The specimens were prepared according to the ASTM E606 and ASTM E1820 standards which were then subjected to two types of cyclic loading amplitude modes namely constant amplitude and random amplitude. The effort is initiated by implementing fatigue data editing approach for random amplitude signal, the conventional method, the finite element method (FEM) and fatigue assessment determination through the statistical method of root mean square (r.m.s) and kurtosis. The input and edited signal acquired will be analyzed for the prediction of the fatigue damage based on the strain model approaches, i.e. Coffin-Manson, Morrow and SWT. From the results obtained, both edited and non-edited signals load display the same amount of fatigue damage to consequently decrease the analysis duration. In addition, the FEM was found to be the best approach for estimating the fatigue life. This research has finally revealed that the higher cyclic load amplitude will only diminish the fatigue life of a specimen. Furthermore, this fatigue assessment study will look forward to improve structural engineering development in monitoring components and consequently access the damage prediction variable which could later be implemented to the manufacturing industry.

Abstract: This paper discussed on an application of the statistical based analysis approach on fatigue failure of carbon steel. A new statistical based method known as Integrated Kurtosis-based Algorithm for Z-filter (I-kaz) and the quadratic mean were used in this fatigue failure assessment. Fatigue tests were performed according to the ASTM E466-96 standard with the attachment of a strain gauge to the tested specimen. Test was performed at a constant loading leading to the collection of strain data throughout the test. A fatigue based data acquisition system was used in this work. All obtained data were analysed using specific software. Fatigue failure behaviour was observed through the strain signal analysis to investigate significant correlation between I-kaz coefficient, root mean square value and the fatigue failure behaviour. It was found that I-kaz coefficient and root mean square value are proportional to life cycle.

Abstract: Fatigue damage assessment is very important in design process of the component to determine their durability under service loading conditions. In service, the great majority of structures and components are subjected to stress of variable amplitude loading. The purpose of this research is to analyse statistically of two types of strain signals from road loading and compare their effect on fatigue damage of the engine mount bracket. Strain gauges were attached to the engine mount bracket and were connected to the data acquisition set in order to capture the actual strain signals when an automobile was driven on two different road surfaces. The strain signals were then analysed using global signal statistic and integrated kurtosis based algorithm for Z-filter (I-kaz) method. Meanwhile, damage of the engine mount bracket was evaluated using finite element commercial software. From the analysis, it was found that the fatigue damage showed an increment with the respective statistical values of the strain signals.