Indentation Induced Tin Whisker Formation on Tin Plated Component Leads

2005 ◽  
Author(s):  
Jin Liang ◽  
Xiaodong Li ◽  
Zhi-Hui Xu ◽  
Dongkai Shangguan
Keyword(s):  
Stress Level ◽  
Quantitative Relationship ◽  
Whisker Formation ◽  
Tin Whisker ◽  
Element Analysis ◽  
Root Cause ◽  
Stress Threshold ◽  
Calculation Results ◽  
Free Transition ◽  
Metallurgical Reactions

Tin whisker formation has been a serious concern for application of pure Tin as a Pb-free component lead finish. It has been long believed that residual stress is the root cause of whisker formation. A fundamental question is if stress produced by other than the plating processing and post-plating metallurgical reactions can induce whisker formation. In this study, micro indents were made on pure Tin plated component leads to induce stress for studying stress induced whisker formation. Nano-indentation was performed to measure hardness and elastic modulus of the Tin coating layer where whiskers initiate. Scanning electron microscopy (SEM) was used to study indentation deformation mechanisms and to monitor the nucleation and growth of whiskers in-situ. In additions, finite element analysis was carried out to theoretically calculate the stress/strain distribution around the indentations. Experimental and theoretical calculation results show that whiskers form at a certain stress level. This suggests that there might exit a critical stress threshold that governs the whisker formation. It is believed that establishment of a quantitative relationship between stress level and whisker formation/growth could lead to a breakthrough in risk and reliability assessment with pure Tin application in the electronic industry and in safeguard for smooth Pb-free transition.

A Stress Check Procedure for Pipe Lowering-In Process During Pipeline Construction

2014 ◽  
Author(s):  
Da-Ming Duan ◽  
Thomas Jurca ◽  
Charles Zhou
Keyword(s):  
Finite Element ◽  
Stress Level ◽  
Height Profile ◽  
Element Analysis ◽  
Pipeline Construction ◽  
Lifting Capacity ◽  
Calculation Results ◽  
Construction Condition ◽  
Construction Practice

The quality of pipeline construction is determined by the effort of controlling the pipe stress level. Constraints may include various factors, such as pipe size, side boom lifting capacity, the number of side booms, side boom spacing and the lifting height profile. The use of girth weld flaw size limit established by Engineering Critical Assessment (ECA) for a given construction condition, makes the accuracy of pipe stress even more important. This is not only because stress level is one of the controlling parameters of the ECA results, but also because in some cases, such as low girth weld fracture toughness, stress level must be controlled with a very narrow window to keep a meaningful ECA that leads to a reasonable weld repair rate. An optimized pipe lifting height profile can be obtained from stress analysis using finite element method based on available construction equipment capabilities. From a practical perspective, an optimized pipe lowering-in plan may not be executable in the construction field. It is thus desired that a practical approach be provided that captures the key feature of construction practice and at the same time makes the key measures recordable. This paper provides a set of stress check equations derived using beam deformation theory. The calculation results using these equations show that for normal pipe lowering-in practice, pipe stress level can be effectively controlled by checking and controlling the lifting height of just one or two points. The approach proposed is to be used in conjunction with case specific finite element analysis.

Study on Whisker Outbreak on Thin Plating by Contact Force

2006 ◽  
Author(s):  
Takuma Yamashita ◽  
Tadahiro Shibutani ◽  
Qiang Yu ◽  
Masaki Shiratori
Keyword(s):  
Contact Force ◽  
Whisker Formation ◽  
Stress Evolution ◽  
Tin Whisker ◽  
Element Analysis ◽  
Creep Properties ◽  
Compressive Stresses ◽  
Flexible Printed Circuit ◽  
Flex Cable ◽  
Loading Tests

Tin whisker outbreaks can pose problems on FFC/FPC (flat flex cable/flexible printed circuit) connectors in electronics components. Several mechanical loading tests for investigating whisker formation have been performed, however, the mechanical implications of the results remain unclear. The purpose of this study was to clarify whether the whisker formation mechanism on connectors is due to contact force. Using the creep properties collected from nanoindentaion tests, the stress evolution in plating is extracted. The behavior of the stress evolution was investigated by finite element analysis. During the test, the axial compressive stresses increase, although stress relaxation also occurs. The effect of substrate shape is also investigated and whiskering behavior due to stress was confirmed.

Dynamic Analysis of DVG 850 High-Speed Machining Center

2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Response Analysis ◽  
Improved Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Harmonic Response ◽  
Machining Center ◽  
Calculation Results ◽  
Harmonic Response Analysis

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.

Effect of Creep Properties on Pressure Induced Tin Whisker Formation

2008 ◽  
Author(s):  
Tadahiro Shibutani ◽  
Qiang Yu ◽  
Masaki Shiratori
Keyword(s):  
Whisker Formation ◽  
Tin Whisker ◽  
Creep Properties

Finite Element Analysis of Tianerya Trench-Buried Inverted Siphon

2013 ◽  
Vol 804 ◽  
pp. 320-324
Author(s):  
Xiang Zan Xie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Calculation ◽  
Construction Process ◽  
Element Calculation ◽  
Element Analysis ◽  
Operational Process ◽  
Inverted Siphon ◽  
Calculation Results ◽  
Calculation Software

This paper adopts universal finite element calculation software to carry out finite element analysis for Tianerya trench-buried inverted siphon. Researching variation law of the inverted siphons stress and displacement in construction process and operational process. The calculation results further shown design schemes rationality and safety. The analysis results provide a certain reference for design of trench-buried inverted siphon structure.

The Mechanical Mechanism Analysis for Mortar Arch Framework Slope Protection Structure

2013 ◽  
Vol 859 ◽  
pp. 143-148
Author(s):  
Yang Xu ◽  
Ding Ling Li ◽  
Li Peng ◽  
Yan Xiao ◽  
Yi Hua Nie
Keyword(s):  
Finite Element Analysis ◽  
Mechanism Analysis ◽  
Analysis Model ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
Vertical Loading ◽  
Total Displacement ◽  
The Finite Element Analysis ◽  
Calculation Results ◽  
Real Scale

The finite element analysis model was built as the real scale for mortar arch framework slope protection, and the displacement and strain at different points were collected by vertical loading pressure. So the mechanical mechanism can be studied, and the analysis was done between calculation results and testing results of solid miniature model. The studying results show that the point on the arch foot is the worst stress place for each arch, and the total displacement increase nonlinear as the distance from the slope top increases, and the bump phenomenon exists in the bottom of slope, the points are likely to be broken.

Sail Aero-Structures: Studying Primary Load Paths and Distortion

2005 ◽  
Author(s):  
Robert Ranzenbach ◽  
Zhenlong Xu
Keyword(s):  
Aerodynamic Load ◽  
Element Analysis ◽  
Strain Behavior ◽  
Construction Methods ◽  
Load Paths ◽  
Calculation Results ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Field ◽  
The Impact ◽  
Primary Load

A method is described to conduct an integrated Fluid-Structure Interaction (FSI) simulation of sails that is based upon knowledge of the sail’s design shape geometry and membrane material properties. A Finite Element Analysis (FEA) of the sail structure and a Computational Fluid Dynamics (CFD) model of the aerodynamic field are combined and iteratively solved to compute the actual flying shape of the sail under aerodynamic load, the stress strain behavior of the sail membrane, the integrated aerodynamic forces produced by the sail such as driving force and heel moment, and the resulting loads on sheets, halyards, etc. An important contribution of this particular method is the incorporation of wrinkling phenomena into the FEA portion of the calculation. Results from a study of working sails for a 30’ MORC racing yacht designed by Nelson-Marek (NM) in the 1990’s are presented and discussed with particular emphasis on the variability of primary load paths with changing trim and sailing conditions as well as the impact of sail deformation in the direction of relatively small stresses that is often poorly addressed in many proprietary sail construction methods.

Calculation methods of bridge deck for prestressed short rib T-beam bridges

2020 ◽  
pp. 1-13
Author(s):  
Sijia Wang ◽  
Tianlai Yu
Keyword(s):  
Finite Element ◽  
Bridge Deck ◽  
Mechanical Performance ◽  
Test Results ◽  
Analysis Method ◽  
Slab Method ◽  
Element Analysis ◽  
Calculation Results ◽  
Beam Bridge ◽  
T Beam

Because of the low height of the prestressed short rib T-beam bridge and the poor torsion resistance of the main beam, the positive moment in the middle span of the bridge deck will increase correspondingly compared with the normal rib beam bridge. At present, there is little research on the calculation method of the bridge deck of the prestressed short rib T-beam bridge. In this paper, the space finite element method and the continuous one-way slab method are used to calculate the forces on the bridge deck, based on the space finite element method, a finite element elastic supported continuous beam method is proposed to calculate the forces on the bridge deck. By comparing the calculation results of the three methods with the test results, the reasonable calculation method of the bridge deck is studied. The results show that the spatial finite element analysis method can simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge well, the stress calculation results are consistent with the test results, and the calculation accuracy is high, which can be used in the actual engineering design; The finite element analysis method of elastic support continuous beam can also simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge. The concept of the method is clear, the calculation is convenient, and it is more suitable for the application of engineering design; The calculation results of the continuous one-way slab method are too large to be safe for design.

scholarly journals Finite-element analysis and structure optimization of X-O composite seal of cone bit

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402091868
Author(s):  
Shuang Jing ◽  
Anle Mu ◽  
Yi Zhou ◽  
Ling Xie
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Parameters ◽  
Structure Optimization ◽  
Seal Ring ◽  
Test Results ◽  
Element Analysis ◽  
Root Cause ◽  
Sealing Performance ◽  
Distribution Of Stress

The seal is the key part of the cone bit. To reduce the failure probability, a new seal was designed and studied. The sealing performance and structure optimization of the X-O composite seal was analyzed and compared by finite-element analysis. The stress and contact pressure were analyzed to establish the main structural parameters that affect sealing performance and the direction of the structural optimization. By optimizing these structural parameters, including the height, and the radial and axial arc radii, an optimized structure is obtained. The results show that (1) the X-O composite seal can meet the seal requirement, the excessive height of the X seal ring is the root cause of the uneven distribution of stress, pressure, and distortion. (2) A new seal structure is obtained, the distribution of pressure and stress is reasonable and even, and the values of stress and pressure are reduced to avoid distortion and reduce the wear. Finally, the field test results of the X-O composite seal of cone bit showed that the service life of the bit bearing increased by 16% on average and the drilling efficiency increased by 11% on average compared with the original cone bit with the O seal ring.

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