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This paper describes the numerical analysis of planar crack growth in high strength steel API 5L X70 whose crack growth parameter is adopted from experimental compact tension (CT) specimen in previous literature. Apart from the fact that conventional fatigue crack growth specimen has bogus geometry constraints, the Single Edge Notched Tension (SENT) better replicate the crack-tip constraint conditions experienced in structures. Linear elastic fracture mechanics (LEFM) crack orientation is modelled with the finite element method in SENT model considering its geometry functions a/W ratio to determine its crack growth rate based on constant amplitude load. The virtual crack closure technique tool in MSC Marc/Mentat software with adaptive and global remeshing is applied to assess high cycle fatigue crack propagation using the SENT model. The crack growth pattern for the 3-dimensional simulation characteristics is similar with that of the CT Specimen experimental procedure. Furthermore, the results of the crack propagation and the cycle count demonstrated good agreement with bearable discrepancy with maximum percentage difference of about 14.1 % for the HAZ and 6.4% for the weld and parent metal compared to the experimental results from literature.

This paper presents the passengers' perspective towards express bus safety issues based on the driver's behavioural characteristics, providing an important aspect in reducing the accidents in Malaysia. A pilot study with a respondent of 40 people, aged between 16 to 41 years old were conducted in Universiti Kebangsaan Malaysia. The developed questionnaires based on the five-point Likert Scale were implemented to assess the safety perception on express buses, and it has a higher reliability of Cronbach's Alpha score at 0.91. The findings show that more than 45 % of the respondents agreed that dangerous behaviour of express bus drivers were mainly due to the use of mobile during driving (63.33%), tailgating (57.58%) and driving above the given speed limit (48.59%). The reason of this behaviour is insufficient time to stick to running schedules and the shift pattern rotations. In terms of safety precautions, about 77% passengers preferred safety briefing using audio due to its ease in understanding the meaningful instruction. In addition, 97% passengers agreed on the needs of a second driver to ensure a safe journey to their destination. Hence, a proposed mitigated solution such as drivers monitoring is needed by the respective agencies to reduce this careless behaviour that may influence the dangerous driving behaviour.

This paper aims to study the identification of bumps in vibrational signals and develop bump-energy-based durability predictive models for a suspension coil spring. The bump energy of the loading signal is affected by high frequency noises and can lead to inaccurate results. Therefore, it is necessary to eliminate high frequency noise during bump identification. Local regularity analysis was employed to determine the singular points in road signals. Bump signals were then reconstructed from these singular points. Subsequently, bump-energy-based models were developed by correlating with the fatigue lives estimated using the Coffin–Manson, Morrow and Smith–Watson–Topper strain-life models. The results show that the bump signals extracted from the road excitations had a frequency band within 0–50 Hz, indicating that the high frequency noises had been successfully removed during extraction of the bumps. The bump-energy-based models predicted a fatigue life ranging from 3.98x104 to 4x109 cycles within a 95% confidence interval, where the Coffin–Manson-based model showed the highest fatigue life. This is because the Coffin–Manson model did not consider the mean stress effects. When compared with the experimental results, the Coffin–Manson-based model indicates the highest accuracy, given its highest R2 of 0.948. The bump-energy-based models developed in this study contributed an accurate durability prediction of coil springs.