Hua lu

Hua lu
Ryerson University · Department of Mechanical Engineering

PHD

About

9
Publications
832
Reads
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57
Citations
Citations since 2016
0 Research Items
11 Citations
20162017201820192020202120220.00.51.01.52.02.53.0
20162017201820192020202120220.00.51.01.52.02.53.0
20162017201820192020202120220.00.51.01.52.02.53.0
20162017201820192020202120220.00.51.01.52.02.53.0

Publications

Publications (9)
Article
Material and structure evaluation for reliability is a key research area for advanced microelectronics and miniatures. This paper presents a new experimental mechanics-based approach devoted to the evaluation of critical failure conditions for solder materials and assembly structures. Several optical and computer-vision-based metrological technique...
Conference Paper
The paper presents a new study on the method of Projection Speckle Digital Correlation (PSDC) for surface out-of-plane displacement and tilt measurement. Considering that perspective and parallel devices differ substantially in the nature of pattern projection and imaging, four different camera-projector setups are modeled by optical triangulation....
Article
Full-text available
We have successfully demonstrated the application of fiber Bragg grating sensors to detect the solder interconnect debounding between flip chip ball grid array and printed circuit board in four-point bend tests. Four sensors, due to their small size, are surface-mounted on the four-corners of the ball grid array substrate, about 1 mm from the solde...
Article
This paper discusses errors caused by unequal grating pitch in applying the phase-shifted digital grating projection method for object profile measurement. To address the related issues, a new scheme is proposed to effectively improve the uniformity of the projected grating pitch across the object surface with no additional hardware cost. The impro...
Article
Some enhancement measures are studied for improving phase-shifted digital speckle shearography toward time-dependent application, such as the evaluation of materials' time-dependent mechanical behavior. To ensure quick and accurate phase shifting, a liquid-crystal variable retarder and a Wollaston prism are integrated into a compact unit, and an in...
Article
The present study attempts to evaluate the stress-strain hysteresis responses of SAC solder joints in Resistor and FleXBGA144 packages subjected to thermal cyclic loading using several constitutive models. The total deformation of the solder material consists of elastic, rate-independent plastic and rate-dependent creep components. The constitutive...
Conference Paper
A digital speckle correlation (DSC) technique was applied to second level interconnects of flip chip and wire bonded packages in order to measure in-situ deformations induced by temperature cycling. The measurements allowed for the total normal and shear strains to be evaluated at various temperatures for different package types having lead-free an...
Article
The paper presents a hybrid experimental and analytical approach to track the deformation of solder joints in an electronic package subject to a thermal process. The solder joint strain is directly measured using a computer vision technique. The strain measurement is analyzed following an approach that is devised based on an established solder cons...
Article
The paper presents a physics-based hybrid approach to assist the assessment of thermally induced packaging reliability. This method is applicable to prototypes at different stages of development. The approach realizes the efficiency and effectiveness through some special capabilities in identifying reliability critical locations and evaluating defo...

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