Surface mount technology (SMT) is increasingly used in microelectronics to mount components by soldering onto the printed circuit board (PCB). The solder alloys are used as the electrical and mechanical connections between the component and the board. Fatigue failure of solder joints is recognized as a major cause of failure in electronic devices. An approach to this problem is to determine the...

Repetitive tasks in industrial works may contribute to health problems among operators, such as musculo-skeletal disorders, in part due to insufficient control of muscle fatigue. In this paper, a predictive model of fatigue is proposed for repetitive push/pull operations. Assumptions generally accepted in the literature are first ex1 plicitly set in this framework. Then, an earlier static fatig...

A polycyclic fatigue damage model for short glass fibre reinforced thermoplastics is developed and implemented into ABAQUS FE code using UMAT subroutine. The MNL model is introduced here in terms of damage rates: ( ) ) ( 2 0 1 2 0 2 1 2 1 1 ) ( ) ( N ij ij ij ij ij ij ij ij ij ij ij e E E N d d λ β ε γ ε β β α − −       +       + = ∂ ∂ = & (1) Where N is the number of cycles. αij, β...

Fretting fatigue process have many features such as early stage crack initiation at contact edge, very slow crack propagation and fatigue failure after very long life operation. In this paper at first we present fretting fatigue model in high cycle region, which is considering the wear process near contact edge. And then we present fretting fatigue life estimation method in low cycle fatigue re...

F atigue is ubiquitous but it is more common and more severe in patients with acute and chronic conditions, including stroke. The reported proportion of people with fatigue after stroke ranges from 23% to 75%. 1 The variation in proportion between studies reflects the heterogeneity in the studied populations , time since stroke, and assessment methods for fatigue. Fatigue is common immediately ...

BACKGROUND The objective of this research was to develop a disease-specific measure for fatigue in patients with motor neurone disease (MND) by generating data that would fit the Rasch measurement model. Fatigue was defined as reversible motor weakness and whole-body tiredness that was predominantly brought on by muscular exertion and was partially relieved by rest. METHODS Qualitative interv...

objective(s):sub-health has been described as a chronic condition of unexplained deteriorated physiological function, which falls between health and illness. in the present study, we evaluated the effects of lycium barbarum polysaccharide (lbp), a polysaccharide fraction purified from lycium barbarum (l. barbarum) on the sub-health mice. materials and methods:the sub-health model mice were buil...

We develop a phenomenological model of electro-mechanical ferroelectric fatigue based on a ferroelectric cohesive law that couples mechanical displacement and electric-potential discontinuity to mechanical tractions and surface-charge density. The ferroelectric cohesive law exhibits a monotonic envelope and loading-unloading hysteresis. The model is applicable whenever the changes in properties...

We investigate the use of cohesive theories of fracture, in conjunction with the explicit resolution of the near-tip plastic fields and the enforcement of closure as a contact constraint, for the purpose of fatiguelife prediction. An important characteristic of the cohesive laws considered here is that they exhibit unloadingreloading hysteresis. This feature has the important consequence of pre...