Reliability of SnAgCu Interconnections with Minor Additions of Ni or Bi under Mechanical Shock Loading at Different Temperatures

2007 ◽  
Author(s):  
T. T. Mattila ◽  
E. Kaloinen ◽  
A. Syed ◽  
J. K. Kivilahti
Keyword(s):  
Shock Loading ◽  
Mechanical Shock ◽  
Different Temperatures

The Reliability of Microalloyed Sn-Ag-Cu Solder Interconnections Under Cyclic Thermal and Mechanical Shock Loading

2014 ◽  
Vol 43 (11) ◽  
pp. 4090-4102 ◽  
Author(s):  
Toni T. Mattila ◽  
Jussi Hokka ◽  
Mervi Paulasto-Kröckel
Keyword(s):  
Shock Loading ◽  
Mechanical Shock

Analytical Determination of Shock Response Spectra for an Impulse-Loaded Proportionally Damped System

Volume 1 ◽  
2004 ◽  
Author(s):  
R. David Hampton ◽  
Nathan S. Wiedenman ◽  
Ting H. Li
Keyword(s):  
Transient Response ◽  
Shock Loading ◽  
Response Spectrum ◽  
Response Spectra ◽  
Analytical Determination ◽  
System Response ◽  
Mechanical Shock ◽  
Shock Response ◽  
Mass Spring ◽  
The Impact

Many military systems must be capable of sustained operation in the face of mechanical shocks due to projectile or other impacts. The most widely used method of quantifying a system’s vibratory transient response to shock loading is called the shock response spectrum (SRS). The system response for which the SRS is to be determined can be due, physically, either to a collocated or to a noncollocated shock loading. Taking into account both possibilities, one can define the SRS as follows: the SRS presents graphically the maximum transient response (output) of an imaginary ideal mass-spring-damper system at one point on a flexible structure, to a particular mechanical shock (input) applied to an arbitrary (perhaps noncollocated) point on the structure, as a function of the natural frequency of the imaginary mass-spring-damper system. For a response point sufficiently distant from the impact area, many Army platforms (such as vehicles) can be accurately treated as linear systems with proportional damping. In such cases the output due to an impulsive mechanical-shock input can be decomposed into exponentially decaying sinusoidal components, using normal-mode orthogonalization. Given a shock-induced loading comprising such components, this paper provides analytical expressions for the various common SRS forms. The analytical approach to SRS-determination can serve as a verification of, or an alternative to, the numerical approaches in current use for such systems. No numerical convolution is required, because the convolution integrals have already been accomplished analytically (and exactly), with the results incorporated into the algebraic expressions for the respective SRS forms.

Fatigue Delamination Crack Growth of Potting Compounds in PCB/Epoxy Interfaces Under Flexure Loading

2019 ◽  
Author(s):  
Pradeep Lall ◽  
Kalyan Dornala ◽  
Jeff Suhling ◽  
John Deep ◽  
Ryan Lowe
Keyword(s):  
Crack Growth ◽  
Shock Loading ◽  
Interfacial Crack ◽  
Mechanical Shock ◽  
Interfacial Delamination ◽  
Ultimate Elongation ◽  
Compound C ◽  
Stiff Material ◽  
Number Of Cycles ◽  
Potting Compound

Abstract Electronics components operating under extreme thermo-mechanical stresses are often protected with underfills and potting encapsulation to isolate the severe stresses. By encapsulating the entire PCB, the resin provides complete insulation for the unit thereby combining good electrical properties with excellent mechanical protection. In military and defense applications these components are often subjected to mechanical shock loads of 50,000g and are expected to perform with reliability. Due to the bulk of material surrounding the PCB, potting and encapsulation resins are commonly two-part systems which when mixed together form a solid, fully-cured material, with no by-products. The cured potting materials are prone to interfacial delamination under dynamic shock loading which in turn potentially cause failures in the package interconnects. The study of interfacial fracture resistance in PCB/epoxy potting systems under dynamic shock loading is important in mitigating the risk of system failure in mission critical applications. In this paper, three types of epoxy potting compounds were used as an encapsulation on PCB samples. The potting compounds were selected based on their ultimate elongation under quasi-static loading. Potting compound, A is a stiffer material with 5% of ultimate elongation before failure. Potting compound, B is a moderately stiff material with 12% ultimate elongation. Finally, potting compound C is a softer material with 90% ultimate elongation before failure. The fracture properties and interfacial crack delamination of the PCB/epoxy interface were determined using three-point bend loading with a pre-crack at the interface. The fatigue crack growth of the interfacial delamination was characterized for the three epoxy systems. A prediction of number of cycles to failure and the performance of different epoxy system resistance under cyclic bending loading was assessed.

Practical Assessment of Electronic Circuit Cards Under Mechanical Shock Loading

2005 ◽  
Vol 48 (1) ◽  
pp. 62-74
Author(s):  
Thomas Stadterman ◽  
Donald Barker
Keyword(s):  
Shock Loading ◽  
Electronic Circuit ◽  
Circuit Board ◽  
Mechanical Shock ◽  
Printed Wiring Boards ◽  
Element Analysis ◽  
Us Army ◽  
Failure Risk ◽  
Assessment Approach ◽  
Component Failures

This paper presents a practical approach for assessing electronic circuit cards for mechanical shock loading. The approach is comprised of three areas: determining board response, assessing damage to the printed wiring boards, and assessing damage to the components. Determining the board response to the shock loading provides the basis for the damage assessments. To determine board response, the approach recommends specific structures to model and finite element analysis (FEA) methods to use. Failure models for circuit board and component failures are provided in terms of failure risk. To demonstrate this practical assessment approach, an example of a US Army circuit card from a computer assembly mounted on a tracked vehicle is provided. This practical assessment approach will allow electronic circuit card designers to quickly evaluate circuit cards with minimal testing and FEA. It also provides information necessary for circuit card redesign to improve failure risk for shock loading.

Study the effect of electrical and mechanical shock loading on liberation and milling characteristics of mineral materials

2015 ◽  
Vol 70 ◽  
pp. 207-216 ◽  
Author(s):  
Veerendra Singh ◽  
I. Obed Samuelraj ◽  
R. Venugopal ◽  
G. Jagadeesh ◽  
P.K. Banerjee
Keyword(s):  
Shock Loading ◽  
Mechanical Shock ◽  
Milling Characteristics

Reliability of CSP Interconnections Under Mechanical Shock Loading Conditions

2006 ◽  
Vol 29 (4) ◽  
pp. 787-795 ◽  
Author(s):  
Toni T. Mattila ◽  
Pekka Marjamaki ◽  
Jorma K. Kivilahti
Keyword(s):  
Shock Loading ◽  
Mechanical Shock ◽  
Loading Conditions
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