Hybrid Simulation Method for PWB Level Drop Tests

2005 ◽  
Author(s):  
Jiansen Zhu ◽  
Esa Hussa ◽  
Juscelino Okura ◽  
Santosh Shetty
Keyword(s):  
Large Deformation ◽  
Simulation Method ◽  
Standard Test ◽  
Test Method ◽  
Drop Test ◽  
Nonlinear Material ◽  
Time Curve ◽  
Impulse Duration ◽  
Drop Tests ◽  
The Impact

PWB level drop tests are widely used as a standard test method to evaluate the reliability of PWB and packages under drop conditions (JEDEC Standard JESD22-B104-A). The drop height and test setup need be adjusted in order to achieve the requirements of a peak shock of 1500g and an impulse duration of 0.5 ms. Generally, the ground need be covered with a thin layer of rubber pad to absorb some of the impact energy. However, this rubber pad will bring challenges for modelling due to large deformation, nonlinear hyperelasticity, and contact. And sometimes, it may also cause the convergence problem. Therefore, a hybrid drop simulation method was developed. This hybrid method can not only circumvent the difficulties mentioned, but also increase the efficiency and reduce the CPU time of PWB drop simulation. When simulating a PWB board level drop test, generally, not only the PWB and the components assembled on it need be modelled, but also the drop vehicle, rubber pad, and ground should be included in the model. For the hybrid drop simulation, however, only part of drop vehicle need be modeled and there is no need to model the ground and the contact between the ground and the drop vehicle. Then an acceleration time curve measured from drop test is applied to the hybrid model so that the responses of the model will mimic the real drop situation. In this way, not only the simulation time is reduced due to smaller model sizes, but also can some difficulties related to large deformation, contact, and nonlinear material properties be avoided. Finally, a comparison of a bare PWB and a populated PWB drop cases was used to validate this hybrid drop simulation method. A reasonable correlation was achieved.

scholarly journals Best practices for selection and application of firefighting foam

2018 ◽  
Vol 247 ◽  
pp. 00014 ◽  
Author(s):  
Joanna Rakowska
Keyword(s):  
Raw Materials ◽  
Environmental Safety ◽  
Standard Test ◽  
Test Method ◽  
Immiscible Liquids ◽  
Performance Effectiveness ◽  
Film Forming ◽  
And Performance ◽  
The Impact ◽  
Inappropriate Choice

The article provides studies concerning the selection for the usage of firefighting foam in the aspect of human, property, environmental safety and sustainable development. Foam concentrates are products of the chemical industry, which, due to the type of raw materials, technology, usage method and waste disposal involved, are an important element of the industrial and environmental safety. Considering the range of extinguishing concentrates available on the market, with their different scope and performance effectiveness, it is necessary to responsibly plan purchases of required extinguishing agents. For testing all types of firefighting foam agent: synthetic, aqueous film forming, protein, fluoroprotein and fluoroprotein film forming concentrates were used. The standard test method ISO 7203-1:2011 for low-expansion foams used for the control, extinction and inhibition of reignition of fires of water-immiscible liquids was applied. The use of an appropriately selected and properly concentrated firefighting foam to extinguish a fire allows decreasing the duration of the fire and its consequences for the environment. The amount of used extinguishing agents will be substantially smaller. In the article the impact of considered use of firefighting foams on their effectiveness and potential dangers resulting from an inappropriate choice was shown.

Comparison of Failure for HBM ESD Testers Meeting ANSI/ESD S-5.1 or the New ESDA Standard Test Method and JEDEC Standard

1998 ◽  
Author(s):  
Fred Khosropour ◽  
Colin Hatchard ◽  
Ian Morgan ◽  
Leo G. Henry
Keyword(s):  
Cmos Technology ◽  
Standard Test ◽  
Test Method ◽  
Physical Analysis ◽  
Human Body Model ◽  
Standard Test Method ◽  
Technology Products ◽  
Discharge Model ◽  
The Impact ◽  
First Time

Abstract The ESD Association standard ANSI/ESDA S-5.1 1993 for testing sensitivity to the Human Body Model (HBM) 1 forms the basis around which the majority of automated HBM ESD simulators have been constructed. As device pin counts increase it is unlikely that new larger simulators for > 512 pins will be capable of meeting this standard 2, since increased parasitics will increase the effective socket (stray) capacitance. However, such larger HBM simulators are expected to meet both the JEDEC Standard JESD-22-114A, 1997 3 and the newly issued ESDA Standard Test Method, ESD STM 5.1, 19984. This paper begins to evaluate the several questions regarding the correlation of HBM Withstand Voltage when used to characterize state-of-the-art semiconductor IC's, between simulators meeting the (NEW) standards JESD 22, ESD STM- 5.1 and those existing simulators presently in daily use, which typically meet the (OLD) ESDA S-5.1. This paper for the first time investigates the impact of "effective" socket capacitance in the same tester; i.e., with the same discharge model and the same pin selection mechanism. The experimental investigation was based on stressing three different sub-micron CMOS technology products; firstly on a simulator meeting the OLD standard and then on a modified version of this simulator meeting the NEW standards. Electrical properties of damaged pins and physical analysis was used to establish common Failure Signatures5 for the two mother boards.

Mechanical and Thermal Assessment by BAM of a New Package Design for the Transport of SNF From a German Research Reactor

2020 ◽  
Author(s):  
Steffen Komann ◽  
Viktor Ballheimer ◽  
Thomas Quercetti ◽  
Robert Scheidemann ◽  
Frank Wille
Keyword(s):  
Research Reactor ◽  
Drop Test ◽  
Radioactive Material ◽  
Test Facility ◽  
Test Sequence ◽  
Thermal Safety ◽  
Package Design ◽  
Drop Tests ◽  
Approval Procedure ◽  
The Impact

Abstract For disposal of the research reactor of the Technical University Munich FRM II a new transport and storage cask design was under approval assessment by the German authorities on the basis of International Atomic Energy Agency (IAEA) requirements. The cask body is made of ductile cast iron and closed by two bolted lid systems with metal seals. The material of the lids is stainless steel. On each end of the cask the wood-filled impact limiters are installed to reduce impact loads to the cask under drop test conditions. In the cavity of the cask a basket for five spent fuel elements is arranged. This design has been assessed by the Bundesanstalt für Materialforschung und -prüfung (BAM) in view to the mechanical and thermal safety analyses, the activity release approaches, and subjects of quality assurance and surveillance for manufacturing and operation of the package. For the mechanical safety analyses of the package a combination of experimental testing and analytical/numerical calculations were applied. In total, four drop tests were carried out at the BAM large drop test facility. Two tests were carried out as a full IAEA drop test sequence consisting of a 9m drop test onto an unyielding target and a 1m puncture bar drop test. The other two drop tests were performed as single 9m drop tests and completed by additional analyses for considering the effects of an IAEA drop test sequence. The main objectives of the drop tests were the investigation of the integrity of the package and its safety against release of radioactive material as well as the test of the fastening system of the impact limiters. Furthermore, the acceleration and strain signals measured during the tests were used for the verification of finite-element (FE) models applied in the safety analysis of the package design. The FE models include the cask body, the lid system, the inventory and the impact limiters with the fastening system. In this context special attention was paid to the modeling of the encapsulated wood-filled impact limiters. Additional calculations by using the verified numerical model were done to investigate e.g. the brittle fracture of the cask body made of ductile cask iron within the package design approval procedure. The thermal safety assessment was based on analytical energy balance calculations and FE analyses. As an additional point of evaluation in frame of approval procedure, the effect of possible impact limiter burning under accident conditions of transport was considered by the applicant and assessed by BAM. This paper describes the package design assessment from the point of view of the competent authority BAM including the applied assessment strategy, the conducted drop tests and the additional calculations by using numerical and analytical methods.

Model Tests for Evaluating the Impact of Low Viscosity Tailor-Made Biofuels on Tribological Contacts in Injection Pumps

2013 ◽  
Author(s):  
Stefan Heitzig ◽  
Alexander Weinebeck ◽  
Hubertus Murrenhoff
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
Research Approach ◽  
Low Viscosity ◽  
Injection Pump ◽  
The Impact ◽  
Fuel Lubricity

In the scope of the cluster of excellence “Tailor-made Fuels from Biomass” new biofuels are developed within an interdisciplinary research approach at RWTH Aachen University. To ensure a safe and reliable functioning of the new fuels in combination with state of the art fuel injection equipment, every fuel has to fulfil requirements regarding its tribological performance, which depends on characteristics like dynamic viscosity and fuel lubricity. Hence, one focus of the cluster lies on the tribological characteristics of the fuel candidates. Biofuel candidates which have been investigated so far and which are suitable for the use in self-ignition engines as surrogates for fossil diesel fuel tend to have lower viscosities and show varying lubrication behaviour, compared to diesel. As a standard test method for diesel fuel lubricity the HFRR test is well established. Nevertheless, relying on the established diesel-pass/fail criterion, which is defined in several norms, is disputable, since the investigated biofuels differ strongly from modern diesel fuels. To identify the relevant fuel properties and to gain a more detailed understanding of the wear and friction processes within the critical contacts, results of different tribological test methods, including the HFRR test and a disc-on-disc tribometer, are presented, compared and discussed in this paper. In order to estimate the validity of the established HFRR pass/fail criterion for low viscosity biofuels the experimental results are compared to simulation outcomes of elasto-hydrodynamic simulations of the main tribological contacts in a standard common rail injection pump.

scholarly journals Design of custom cranial prostheses combining manufacturing and drop test finite element simulations

2020 ◽  
Vol 111 (5-6) ◽  
pp. 1627-1641
Author(s):  
G. Palumbo ◽  
A. Piccininni ◽  
G. Ambrogio ◽  
E. Sgambitterra
Keyword(s):  
Finite Element ◽  
Manufacturing Process ◽  
Numerical Models ◽  
Thickness Distribution ◽  
Drop Test ◽  
Constant Thickness ◽  
Fe Model ◽  
Flat Disk ◽  
Drop Tests ◽  
The Impact

Abstract In this work, impact puncture tests (drop tests) have been used to both tune numerical models and correlate the performance of customised titanium cranial prostheses to the manufacturing process. In fact, experimental drop tests were carried out either on flat disk-shaped samples or on prototypes of titanium cranial prostheses (Ti-Gr5 and Ti-Gr23 were used) fabricated via two innovative sheet metal forming processes (the super plastic forming (SPF) and the single point incremental forming (SPIF)). Results from drop tests on flat disk-shaped samples were used to define the material behaviour of the two investigated alloys in the finite element (FE) model, whereas drop tests on cranial prostheses for validation purposes. Two different approaches were applied and compared for the FE simulation of the drop test: (i) assuming a constant thickness (equal to the one of the undeformed blank) or (ii) importing the thickness distribution determined by the sheet forming processes. The FE model of the drop test was used to numerically evaluate the effect of the manufacturing process parameters on the impact performance of the prostheses: SPF simulations were run changing the strain rate and the tool configuration, whereas SPIF simulations were run changing the initial thickness of the sheet and the forming strategy. The comparison between numerical and experimental data revealed that the performance in terms of impact response of the prostheses strongly depends on its thickness distribution, being strain hardening phenomena absent due to the working conditions adopted for the SPF process or to the annealing treatment conducted after the SPIF process. The manufacturing parameters/routes, able to affect the thickness distribution, can be thus effectively related to the mechanical performance of the prosthesis determined through impact puncture tests.

Reliability Characterization of Organic Solderability Preservatives (OSP) of IC Packages by Drop and Cyclic Bend Test

2005 ◽  
Vol 297-300 ◽  
pp. 893-898
Author(s):  
Seung Mo Kim ◽  
Eun Sook Shon ◽  
Yoon Hyun Ka ◽  
Yong Joon Kim ◽  
Jin Young Kim ◽  
...  
Keyword(s):  
Standard Test ◽  
Test Method ◽  
Drop Test ◽  
Bend Test ◽  
The Other ◽  
Rate Performance ◽  
Electronic Components ◽  
Cyclic Frequency ◽  
The One

Cyclic bend test and drop test were carried out as a second level reliability test method in order to characterize the joint performance between electronic components and board. Two types of package substrates were used for the test. The one was NiAu plated, and the other one was organic solderability preservatives (OSP) finished. Drop test was done in accordance with JEDEC standard test method [1]. Drop impact and duration time was 1,500G and 0.5ms, respectively. Cyclic bend test was performed with Amkor internal specification because there is no international standard for the test. The Amkor internal specification was edited based on the IPC/JEDEC specification [2]. Board deflection and cyclic frequency was 3mm and 1Hz, respectively. NiAu substrate showed better mean life performance about by 30% in cyclic bend test. OSP substrate showed the same or better failure rate performance in drop test. Typical solder joint failures and intermetalic crack were found by failure analysis.

Drop Test Simulation for the Component-Level Reliability of Module Packages

2010 ◽  
Vol 2010 (1) ◽  
pp. 000220-000226
Author(s):  
Yu Gu ◽  
Daniel Jin
Keyword(s):  
Parametric Modeling ◽  
Drop Test ◽  
Parametric Models ◽  
Component Level ◽  
Test Board ◽  
Module Size ◽  
Drop Tests ◽  
Explicit Dynamic ◽  
Board Level ◽  
The Impact

The component-level drop reliability of micro-electronic packages has been a concern. Proper modeling approaches can significantly reduce the time and costs and provide valued data support not only on the failure analysis but also on product development. Based on finite element methods, the presented study performed explicit dynamic drop modeling to simulate the actual drop tests using ANSYS and LS-DYNA. A generic over-molded LGA (land grid array) module was selected and 3D parametric models were utilized to carry out the study. As in the actual drop test, the standard JEDEC test board and JEDEC drop condition were applied. The over-molded modules together with the test board under 1500G gravity was simulated to identify the failure locations. The results were fairly correlated to the actual FA observation. Potential key factors such as solder pad size, pitch size, module size, and thickness were studied through the parametric modeling. The impact of board side defect, such as solder void, was also studied because it is common to have this kind of defect in assembly. Besides component-level drop reliability, we also studied the board-level drop reliability by investigating the LGA solder stress.

scholarly journals Biomechanical performance of leather and modern football helmets

2013 ◽  
Vol 119 (3) ◽  
pp. 805-809 ◽  
Author(s):  
Steven Rowson ◽  
Ray W. Daniel ◽  
Stefan M. Duma
Keyword(s):  
Technical Note ◽  
Drop Test ◽  
Biomechanical Analysis ◽  
Head Acceleration ◽  
Impact Performance ◽  
Performance Differences ◽  
Football Helmets ◽  
Drop Tests ◽  
The Impact

With the increased national concern about concussions in football, recent research has focused on evaluating the impact performance of modern football helmets. Specifically, this technical note offers a biomechanical analysis of classic leather helmets compared with modern helmets. Furthermore, modern helmets were examined to illustrate the performance differences between the better- and worse-performing ones. A total of 1224 drop tests were performed from a range of drop heights and impact locations on 11 different helmet types (10 modern and 1 leather helmet model). The resulting head acceleration was used to assess the risk of concussion for each drop test. The results of this analysis demonstrate that modern helmets are significantly and substantially superior to leather helmets in all impact scenarios, and that notable differences exist among modern helmets.

The Influence of Turbulence (or Hydrodynamic Effects) on Strontium Sulphate Scale Formation and Inhibitor Performance

2014 ◽  
Author(s):  
Clare Johnston ◽  
Louise Sutherland
Keyword(s):  
Barium Sulphate ◽  
Test Methods ◽  
Standard Test ◽  
Field Application ◽  
Scale Formation ◽  
Test Method ◽  
Scale Inhibitor ◽  
Modified Method ◽  
Bottle Test ◽  
The Impact

Abstract Inorganic scale (carbonate, sulphate and sulphides) formation can be predicted from thermodynamic models and over recent years better kinetic data has improved the prediction of such scales in field conditions. However these models have not been able to predict the observed deposition where flow disturbances occur, such as at chokes, tubing joints, gas lift valves and safety valves. This can lead to unexpected failures of critical equipment such as downhole safety valves (DHSV’s), and operational issues such as failure to access the well for coiled tubing operations due to tubing restrictions. In recent years it has been recognised that the turbulence found at these locations increases the likelihood of scale formation and experiments have been able to demonstrate that increased turbulence also impacts the minimum scale inhibitor concentration required to prevent scale. One of the industry standard test methods used to screen inhibitors for sulphate scale inhibition is the static bottle test. In this paper the ‘static’ bottle test method is modified to investigate the effects of increasing levels of turbulence on the formation of strontium sulphate scale at a fixed brine composition. Using this modified method it has been possible to demonstrate the impact of varying turbulence on the performance of two common generic types of scale inhibitor (phosphonate and vinyl sulphonate co-polymer). Data on the mass of scale formed, scale morphology using SEM imaging and inhibitor efficiency will be linked to degree of turbulence and scale inhibitor functionality (nucleation inhibition vs. crystal growth retardation). This study builds on the previously published10 findings for barium sulphate which showed phosphonates were less affected by turbulent conditions by carrying out similar tests on strontium sulphate. A clear mechanistic conclusion can now be drawn for sulphate scale formation and inhibition under increasingly turbulent conditions. The findings from this study have a significant impact on the methods of screening scale inhibitors for field application that should be utilised and development of suitable inhibitors that perform better under higher shear conditions.

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