An efficient online time-temperature-dependent creep-fatigue rainflow counting algorithm

Fotuhi‐Firuzabad

et al. 2020

Sci Rep

Self Cite

The quantity and variety of parameters involved in the failure evolutions in solder joints under a thermo-mechanical process directs the reliability assessment of electronic devices to be frustratingly slow and expensive. To tackle this challenge, we develop a novel machine learning framework for reliability assessment of solder joints in electronic systems; we propose a correlation-driven neural network model that predicts the useful lifetime based on the materials properties, device configuration, and thermal cycling variations. The results indicate a high accuracy of the prediction model in the shortest possible time. A case study will evaluate the role of solder material and the joint thickness on the reliability of electronic devices; we will illustrate that the thermal cycling variations strongly determine the type of damage evolution, i.e., the creep or fatigue, during the operation. We will also demonstrate how an optimal selection of the solder thickness balances the damage types and considerably improves the useful lifetime. The established framework will set the stage for further exploration of electronic materials processing and offer a potential roadmap for new developments of such materials.

Section: Proposed Methodologymentioning

confidence: 99%

Correlation-driven machine learning for accelerated reliability assessment of solder joints in electronics

Fotuhi‐Firuzabad

et al. 2020

Sci Rep

Self Cite

“…Variations of these algorithms are included in the American Society for Testing and Materials (ASTM) cycle counting standard [29]. Among all of the cycle-counting algorithms, the rain-flow counting method has gained abundant attraction owing to its simplicity of implementation and insignificant errors [30]- [32]. The three-and four-point are two major versions of the rain-flow counting method that were proven to be equivalent by McInnes and Meehan [30].…”

Section: Related Workmentioning

confidence: 99%

Online Evaluation of Turbo-Generator Shaft Fatigue Damage Caused by Subsynchronous Oscillation

Chen

Zhang

2020

IEEE Access

Subsynchronous oscillation (SSO) fault can cause torsional vibration and fatigue damage of the shafting system, thereby endanger the safe operation of the turbo-generator set. A novel framework for the online evaluation of shaft fatigue damage suffered from SSO is proposed in this paper. The main ingredients of the framework are a calculation method of the turbo-generator shaft torque, rain-flow counting method, S-N curves and linear damage accumulation law. The shaft torque calculation method, based on the measured torsional angle and generator voltage and current data, is mainly discussed. The effects of damping and electromechanical coupling under complex operating conditions are included in the measured data, and the calculated results of the torque are accurate. The novel framework was used to evaluate the fatigue damage of a 1000 MW turbo-generator shaft that suffered an actual SSO fault caused by a high-voltage direct current (HVDC) transmission system and some meaningful conclusions were given.

“…Parameter k ≥ 0 stands for the curvature of projection which is linear for k = 0, and tends to the unit Heaviside step function for k → ∞. Further, in order to remove the effect of "chess plane", we define a target function in the approximation process in the form of a linear combination of function (11) and additionally introduced penalty function of the following form:…”

Section: Formulation Of Topological Optimization Problemmentioning

confidence: 99%

“…In [9], these stresses causing the destruction of soldered joints were mathematically modeled using software and a comparison was made with experimental results. The thermomechanical reliability of the solder connection has been extensively investigated using finite element method [10,11].…”

Section: Introductionmentioning

confidence: 99%

Decreasing Shear Stresses of the Solder Joints for Mechanical and Thermal Loads by Topological Optimization

et al. 2020

A methodology for obtaining the optimal structure and distribution for the gradient properties of a material in order to reduce the stress level in a soldered joint was constructed. The developed methodology was based on a combination of topological optimization methods (the moving asymptotes method) and the finite elements method; it was first implemented to solve problems of optimizing soldered joints. Using the proposed methodology, a number of problems were solved, allowing one to obtain optimal structural characteristics, in which a decrease in stress is revealed. Designing compounds using this technique will provide more robust designs. The proposed technique can be applied to a wide class of practical problems.