A micromechanical model is presented to study the initiation and propagation of microcracks of intermetallic compounds(IMCs)in solder joints.The effects of the grain aggregate morphology,the grain boundary defects and...A micromechanical model is presented to study the initiation and propagation of microcracks of intermetallic compounds(IMCs)in solder joints.The effects of the grain aggregate morphology,the grain boundary defects and the sensitivity of the various cohesive zone parameters in predicting the overall mechanical response are investigated.The overall strength is predominantly determined by the weak grain interfaces;both the grain aggregate morphology and the weak grain interfaces control the crack configuration;the different normal and tangential strengths of grain interfaces result in different intergranular cracking behaviors and play a critical role in determining the macroscopic mechanical response of the system.展开更多
With the skyrocketing development of technologies,there are many issues in information security quantitative evaluation(ISQE)of complex heterogeneous information systems(CHISs).The development of CHIS calls for an ISQ...With the skyrocketing development of technologies,there are many issues in information security quantitative evaluation(ISQE)of complex heterogeneous information systems(CHISs).The development of CHIS calls for an ISQE model based on security-critical components to improve the efficiency of system security evaluation urgently.In this paper,we summarize the implication of critical components in different filed and propose a recognition algorithm of security-critical components based on threat attack tree to support the ISQE process.The evaluation model establishes a framework for ISQE of CHISs that are updated iteratively.Firstly,with the support of asset identification and topology data,we sort the security importance of each asset based on the threat attack tree and obtain the security-critical components(set)of the CHIS.Then,we build the evaluation indicator tree of the evaluation target and propose an ISQE algorithm based on the coefficient of variation to calculate the security quality value of the CHIS.Moreover,we present a novel indicator measurement uncertainty aiming to better supervise the performance of the proposed model.Simulation results show the advantages of the proposed algorithm in the evaluation of CHISs.展开更多
基金supported by the NationalNatural Science Foundation of China (NSFC) under Grant 11872078,and Beijing Natural Science Foundation No.3222005.
文摘A micromechanical model is presented to study the initiation and propagation of microcracks of intermetallic compounds(IMCs)in solder joints.The effects of the grain aggregate morphology,the grain boundary defects and the sensitivity of the various cohesive zone parameters in predicting the overall mechanical response are investigated.The overall strength is predominantly determined by the weak grain interfaces;both the grain aggregate morphology and the weak grain interfaces control the crack configuration;the different normal and tangential strengths of grain interfaces result in different intergranular cracking behaviors and play a critical role in determining the macroscopic mechanical response of the system.
基金supported in part by the National Key R&D Program of China under Grant 2019YFB2102400,2016YFF0204001in part by the BUPT Excellent Ph.D.Students Foundation under Grant CX2019117.
文摘With the skyrocketing development of technologies,there are many issues in information security quantitative evaluation(ISQE)of complex heterogeneous information systems(CHISs).The development of CHIS calls for an ISQE model based on security-critical components to improve the efficiency of system security evaluation urgently.In this paper,we summarize the implication of critical components in different filed and propose a recognition algorithm of security-critical components based on threat attack tree to support the ISQE process.The evaluation model establishes a framework for ISQE of CHISs that are updated iteratively.Firstly,with the support of asset identification and topology data,we sort the security importance of each asset based on the threat attack tree and obtain the security-critical components(set)of the CHIS.Then,we build the evaluation indicator tree of the evaluation target and propose an ISQE algorithm based on the coefficient of variation to calculate the security quality value of the CHIS.Moreover,we present a novel indicator measurement uncertainty aiming to better supervise the performance of the proposed model.Simulation results show the advantages of the proposed algorithm in the evaluation of CHISs.
