Drop Test Analysis Research Articles

Structure Optimization of Large-Diameter Percussive Drill

The second and the third end faces of the tube support plate of the large-diameter percussive drill are prone to fracture. The structure optimization of large-diameter percussive drill is carried out in this paper. The fully closed structure is turned into semi-closed structure. The reinforcing rib is arranged. With a drop test analysis, the optimized structure can effectively reduce the stress of the drill.

Computer Simulation of Fracture Damage for Large-Diameter Percussive Drill

A large-diameter trapezium percussive drill modeling is made by finite element modeling software and a computer simulation study of the drill is carried out in this paper. By a drop test analysis, the stress changes of each trapezoid faces is showed and the the larger stressed places are found out in this paper.The larger stressed places are easy to be fracture damaged.The beneficial theory basis will be provided by this simulation for the structural optimization of large-diameter percussive drill.

A palladium chelating complex of ionic water-soluble nitrogen-containing ligand: the efficient precatalyst for Suzuki–Miyaura reaction in water

An ammonium-functionalized water-soluble bidentate nitrogen-containing ligand (3) and its palladium chelating complex (4) have been easily prepared from the commercial available starting materials in high overall yields. The charge distributions and molecular orbital analyses of 3, 4 and non-ionic hydrophobic analogue (2a) based on the optimized structures were implemented. The crystal structure of 4 has been established by single-crystal X-ray diffraction. The water-soluble palladium complex was a much more effective catalyst than 2a in palladium-catalyzed Suzuki–Miyaura cross-coupling reaction in air and pure water. High catalytic activity of aryl chlorides and aryl bromides was observed. The mercury drop test, poison experiments and TEM analysis of the catalytic solution showed Pd(0) were involved in catalysis. The palladium nanoparticles of 3.0 ± 0.6 nm were formed after the catalytic reaction, they were stabilized by synergetic effect of coordination and electrostatic interactions from the ammonium-functionalized chelating ligand. No precipitate was observed when the aqueous nanoparticles were stored in air for months.

Rate-dependent constitutive model of poly(ethylene terephthalate) for dynamic analysis

Uniaxial tensile testing at strain rates ranging from 10^(-3) to 10^(-1) s^(-1) was carried out to study the rate-dependent mechanical behavior for poly(ethylene terephthalate) (PET) used in the packaging industry. The experimental results show that a rate-dependent plastic behavior exists for PET material. The value of the yield strength was found to increase with the increasing strain rate. A new constitutive model based on the improved Cowper-Symonds rate-dependent constitutive model is proposed to describe the mechanical behavior of PET material in the strain rate ranging from 10^(-3) to 10^(-1) s^(-1), providing more accurate material data for the subsequent simulation analysis of drop test and dynamic buckling. The predictions obtained using the proposed model are compared with experimental results of the improved Cowper-Symonds model. The simulating results of the proposed model agree well with the experimental data. For a low strain rate, the predictions of this model are more precise than those obtained using the improved Cowper-Symonds model. This confirms that the new constitutive model is suitable for describing the mechanical behavior of PET material at a low strain rate and modeling impact problem.

Board Level Drop Test Analysis Based on Modal Test and Simulation

Solder joint reliability in drop test is crucial for handheld systems, such as mobile phone, digital camera, and MP3 player. In recent years, a lot of experiments and simulations have been carried out by researchers to study board level drop test, and many useful results have been obtained. Regarding mechanical simulation and analysis, there are still two challenges: How to design drop test printed circuit board (PCB) based on dynamic simulation and analysis? How to get accurate elastic modulus of PCB, especially damping parameters, as property inputs for drop test simulation? In this study, an approach based on systematic modal tests and analyses is used to address these two challenges. First, modal dynamic simulation is used to design the test board to meet drop test requirements. Second, modal tests are conducted on drop test board in order to validate dynamic simulation and measure structural damping parameters and overall board elastic modulus as well. Adopted directly in drop test simulation, the measured damping parameters and elastic modulus are proved to be accurate. It is verified through comparison between the finite element simulation and real drop test results. With the modal tests and simulation method established here, drop simulation becomes very simple and accurate, and test board design and characterization are also simplified. Thus, considerable drop test experiment and simulation fine tune, and validation work can be saved.

Mechanical Event Simulation of Drop Testing for Toy Product

Toys that are free from drop failures normally take a long time to develop. It is often time and cost consuming after the production tooling is built to detect drop test failure. This paper introduces a new drop testing analysis method for Toys. The method uses a simple approach with a local analysis that based on the linear and non linear finite element analysis. Modeling and transient drop analysis of a pre-school toy is used as a case study to demonstrate the method. The impact analysis of the product hitting the solid concrete floor after a free fall is presented. The analysis focuses on the deformation of the housing for a product with electronic circuit and mechanical mechanism inside. Experimental data has been obtained for drop simulation of the housing and its correlation with the plastic material properties. The stress and strain of the housing during drop impact tests are noted. The effects of the material properties to the housing deflection under drop/impact shock have been investigated. Numerical results are compared with experimental results to validate the method.

Support excitation scheme for transient analysis of JEDEC board-level drop test

We propose in this paper the support excitation scheme for analyzing transient structural responses of electronic components subjected to JEDEC board-level drop test conditions. Equations of motion of the board-level test vehicle are derived based on coordinate transformations that translate the input acceleration pulse into the effective support excitation load on the test vehicle. In this way, modeling of the drop table along with calculations for the impact force on the drop table through contact methodologies can be omitted. Furthermore, either an explicit or an implicit solver works for the numerical model. Compared with the conventional numerical treatment for board-level drop tests, this novel methodology provides computationally economical solutions. With the support excitation scheme implemented, numerical studies are carried out to investigate efficiencies of implicit and explicit time integration schemes, solution accuracies with respect to the mesh density of the test board, and effects of drop orientations as well as structural damping on transient structural responses of a board-level chip-scale package subjected to the JEDEC drop test condition.

Initial global-local analysis for drop-impact effect study of TV products

The drop test analysis by using finite element method (FEM) needs effective techniques to achieve solutions within reasonable computational time. Therefore a global-local (GL) model is suggested in this work to reduce the computation time of the whole solution process with a reasonable accuracy. The proposed GL method is used to analyze a large-scale finite element TV model with complex and detailed components. The possibility of partial breaking of TV undergoing impact-contact condition is discussed. It also shows that the impact problem of TV finite element model with complex and a large number of detailed components in impact problem can be solved with an existing software within reasonable computational time. The Hertz's theory is also used in this work to reduce the impact force of the original model by changing certain properties. The results obtained through different parameters are presented and discussed.

Initial global-local analysis for drop-impact effect study of TV products

The drop test analysis by using finite element method (FEM) needs effective techniques to achieve solutions within reasonable computational time. Therefore a global-local (GL) model is suggested in this work to reduce the computation time of the whole solution process with a reasonable accuracy. The proposed GL method is used to analyze a large-scale finite element TV model with complex and detailed components. The possibility of partial breaking of TV undergoing impact-contact condition is discussed. It also shows that the impact problem of TV finite element model with complex and a large number of detailed components in impact problem can be solved with an existing software within reasonable computational time. The Hertz's theory is also used in this work to reduce the impact force of the original model by changing certain properties. The results obtained through different parameters are presented and discussed.

光ディスク集合梱包箱落下衝撃解析(S62-2 機構・制御(2),S62 情報機器コンピュータメカニクス)

Fujitsu has developed the drop test analysis technology of PET wrapping structure of the magnetic disk and corrugated cardboard wrapping structure of mobile PC. The optical disk unit is transported by corrugated cardboard box. This time, an analysis technology to design the buffer structure to the dropping impact was constructed. The automatic contact function was used because there were a lot of contact conditions. Stress strain warp curve of the corrugated cardboard was measured. We simulated the acceleration and the action time. We achieved the good correlation of analysis and experiment and will introduce this simulation technology in this announcement.

2404 光ディスク集合梱包箱落下衝撃解析

Fujitsu has developed the drop test analysis technology of PET wrapping structure of the magnetic disk and corrugated cardboard wrapping structure of mobile PC. The optical disk unit is transported by corrugated cardboard box. This time, an analysis technology to design the buffer structure to the dropping impact was constructed. The automatic contact function was used because there were a lot of contact conditions. Stress strain warp curve of the corrugated cardboard was measured. We simulated the acceleration and the action time. We achieved the good correlation of analysis and experiment and will introduce this simulation technology in this announcement.

Non‐destructive packaging seal strength analysis and leak detection using ultrasonic imaging

AbstractThis study investigated the effectiveness of ultrasonic imaging for non‐destructive assessment of seal strength in 335 ml polymeric trays. In the first part of this study, the experimental procedures involved filling sample trays with beef enchilada, then sealing at temperatures of 170–260°C for 5 s at 3 bar. Ultrasonic measurements were conducted using an immersion technique in pulse/echo mode. The captured signal amplitudes of the reflections from the samples were digitized and analysed to construct high‐resolution C‐scan ultrasonic images of the seals. The acquired data were statistically analysed for each sample and used as a basis for comparison with the seal (peel) strength, measured as the energy at break. The energy at break was obtained from destructive peel strength analysis, performed using a tensile testing frame. In the second part of this study, ultrasonic imaging was used to predict the performance of the heat sealer used to fabricate the test trays by comparing the seal quality of each of the four quadrants of the samples trays. This study also investigated the minimum channel leak size that could be detected using this ultrasound system. The results of the peel strength analyses showed that a direct correlation exists between seal strength and sealing temperature (170–227°C). Results of the ultrasonic imaging showed that the statistical scatter in the signal amplitude decreased as the sealing temperature increased. This reduction in the scatter of the signal amplitudes indicated a trend of increasing uniformity in the fusion of the two seal faces. Between 170°C and 193°C, sharp changes in the scatter were observed; however, little change was noted for sealing temperatures greater than 193°C, indicating that 204°C could be a minimum recommended sealing temperature. To confirm this result, a drop test analysis was performed on trays filled with beef enchilada and sealed at temperatures of 170–260°C for 5 s at 3 bar. Results of this drop test confirmed that 204°C was the minimum critical sealing temperature. Based on these results, ultrasonic imaging appeared to offer a promising non‐destructive method for the prediction of seal quality in polymeric trays, sealing equipment monitoring and identification of channel leaks ⩾20 µm in diameter, and is comparable with the more established destructive peel strength analytical method. Copyright © 2003 John Wiley & Sons, Ltd.

An intelligent data mining system for drop test analysis of electronic products

Drop testing is one common method for systematically determining the reliability of portable electronic products under actual usage conditions. The process of drop testing, interpreting results, and implementing design improvements is knowledge-intensive and time-consuming, and requires a great many decisions and judgments on the part of the human designer. To decrease design cycles and, thereby, the time to market for new products, it is important to have a method for quickly and efficiently analyzing drop test results, predicting the effects of design changes, and determining the best design parameters. Recent advances in data mining have provided techniques for automatically discovering underlying knowledge from large amounts of experimental data. In this paper, an intelligent data mining system named decision tree expert (DTE) is presented and applied to drop testing analysis. The rule induction method in DTE is based on the C4.5 algorithm. In our preliminary experiments, concise and accurate conceptual design rules were successfully generated from drop test data after incorporation of domain knowledge from human experts. The data mining approach is a flexible one that can be applied to a number of complex design and manufacturing processes to reduce costs and improve productivity.

Design study of a tritium transport package for future fusion reactors

The first design of a tritium transport package with large capacity and compact size, which can be applicable to tritium transport for International Thermonuclear Experimental Reactor (ITER) was developed. To verify that the package complies with the requirements for the BU type package stipulated in the IAEA regulation of transport packages, structural and thermal analysis were made for hypothetical accident conditions during transport. Structural analysis with the volumetric displacement method (VDM) method under conditions of 9 m drop test and thermal analysis with the ABAQUS code under conditions of 800°C×30 min thermal test showed that the package complied with the requirements for BU type transfer packages. An additional safety analysis was to confirm integrity of the confinement components when the package sinks in the deep sea of 6000 m in depth.

Mechanical and Thermal Safety Analyses and Demonstra Tions For Cubic DCI Multipurpose Containers

A cubic multipurpose container made of ferritic ductile cast iron (DCI) is investigated for the most critical container accident scenarios, a drop from 5 m height flat onto the ground of the German Konrad repository without additional impact limiters and a one hour fire with an average temperature of 800°C. For the mechanical drop test analysis BAM has developed special finite element modelling for numerical calculation of container stresses as the result of such a violent impact. The calculation results are compared with representative strain measurement data from several drop tests with an original prototype container. Referring to the fire test scenario the results from thermal tests by BAM with an original prototype container loaded with representative but inactive ion exchanger resin are presented and discussed.