Influence of Impact Angle and Real Target Properties on Drop Test Results of Cubic Containers

2017 ◽  
Author(s):  
Uwe Zencker ◽  
Linan Qiao ◽  
Holger Völzke
Keyword(s):  
Free Fall ◽  
Impact Angle ◽  
Drop Test ◽  
Storage Site ◽  
Flat Bottom ◽  
Energy Agency ◽  
Accident Scenarios ◽  
Interim Storage ◽  
The Impact ◽  
Real Target

Drop test scenarios with cubic containers without impact limiters at interim storage sites or in a final repository have been investigated by numerical simulations. An ideally flat drop is impossible to conduct as a free fall of a container even under laboratory conditions. Dynamic stresses and strains inside the container structure are sensitive to the impact angle. Even very small impact angles cause remarkable changes in the experimental or numerical results when a flat bottom or wall of a container hits a flat target. For drop tests with transport packages the International Atomic Energy Agency (IAEA) regulations define an essentially unyielding target. In contrast, potential accident scenarios for storage containers are derived from site-specific safety analyses or acceptance criteria in Germany. Each interim storage site or repository has a yielding or so-called real target with individual structural and material properties. The real target acts as a kind of impact limiter. A more conservative container design is required if the impact limiting effect of the target is not considered.

Waste Handling and Storage in the Decontamination Pilot Projects of JAEA for Environments of Fukushima

2013 ◽  
Author(s):  
S. Nakayama ◽  
K. Kawase ◽  
K. Iijima ◽  
M. Kato
Keyword(s):  
Mechanical Stability ◽  
Storage Site ◽  
Pilot Projects ◽  
Energy Agency ◽  
Temporary Storage ◽  
Site Monitoring ◽  
Radiation Monitors ◽  
Waste Handling ◽  
Interim Storage ◽  
Storage Structures

After the Fukushima Daiichi nuclear accident, Japan Atomic Energy Agency (JAEA) was chosen by the national government to conduct decontamination pilot projects at selected sites in Fukushima prefecture. Despite tight boundary conditions in terms of timescale and resources, the projects served their primary purpose to develop a knowledge base to support more effective planning and implementation of stepwise regional remediation of the evacuated zone. A range of established, modified and newly developed techniques were tested under realistic field conditions and their performance characteristics were determined. The results of the project can be summarized in terms of site characterization, cleanup and waste management. A range of options were investigated to reduce the volumes of waste produced and to ensure that decontamination water could be cleaned to the extent that it could be discharged to normal drainage. Resultant solid wastes were packaged in standard flexible containers, labelled and stored at the remediation site (temporary storage until central interim storage becomes available). The designs of such temporary storage facilities were tailored to available sites, but all designs included measures to ensure mechanical stability (e.g., filling void spaces between containers with sand, graded cover with soil) and prevent releases to groundwater (impermeable base and cap, gravity flow drainage including radiation monitors and catch tanks). Storage site monitoring was also needed to check that storage structures would not be perturbed by external events that could include typhoons, heavy snowfalls, freeze/thaw cycles and earthquakes.

Numerical Analysis of Impact Loads on Subsea Structures During Water Entry in Presence of Waves

2020 ◽  
Author(s):  
Gustavo Garcia Momm ◽  
Ivan Fábio Mota de Menezes
Keyword(s):  
Constant Velocity ◽  
Oil And Gas ◽  
Free Fall ◽  
Water Entry ◽  
Gas Production ◽  
Rigid Bodies ◽  
Bottom Surface ◽  
Impact Loads ◽  
Flat Bottom ◽  
The Impact

Abstract Subsea structures employed on offshore oil and gas production systems are likely to be subject to severe loads during deployment. Lowering these structures through the wave zone is a critical operation and the prediction of the loads associated is complex as it involves accelerations of these bodies induced by the vessel motion and the sea surface displacements. This work presents a numerical approach to assessment of the effect of waves on the impact loads that subsea structures are subject to during water entry. A 2D one degree of freedom model using the SPH method was developed to estimate slamming loads on rigid bodies during water entry considering both calm and wavy surfaces. Initially the model was employed to simulate the water entry of wedge considering both free fall and constant velocity cases, obtaining loads profile similar to experiments and numerical simulations from the literature. Later, the constant velocity model was configured to a flat bottom surface rigid body in order to represent a subsea manifold. A regular waves generator provided different wavelength, height and phase enabling slamming load assessment in various situations.

Dynamic Finite Element Analysis of Cask Handling Accidents at Storage Sites

2015 ◽  
Author(s):  
Uwe Zencker ◽  
Linan Qiao ◽  
Holger Völzke
Keyword(s):  
Finite Element ◽  
Small Variation ◽  
Limit Load ◽  
Impact Angle ◽  
Radioactive Material ◽  
Element Analysis ◽  
Dynamic Finite Element ◽  
Calculation Results ◽  
Accident Scenarios ◽  
Interim Storage

The safety assessment of casks for radioactive material at interim storage facilities or in final repositories includes the investigation of possible handling accidents if clearly defined test conditions are not available from the regulations. Specific handling accidents usually are the drop of a cask onto the transport vehicle or the floor as well as the collision with the wall of the storage building or another cask. For such load cases an experimental demonstration of cask safety would be difficult. Therefore, numerical analyses of the entire load scenario are preferred. The lessons learnt from dynamic finite element analyses of accident scenarios with thick-walled cubical containers or cylindrical casks are presented. The dependency of calculation results on initial and boundary conditions, material models, and contact conditions is discussed. Parameter sets used should be verified by numerical simulation of experimentally investigated similar test scenarios. On the other hand, decisions have to be made whether a parameter or property is modeled in a realistic or conservative manner. For example, a very small variation of the initial impact angle of a container can cause significantly different stresses and strains. In sophisticated cases an investigation of simpler limit load scenarios could be advantageous instead of analyzing a very complicated load scenario.

Characterization of Fine Pitch CSP Solder Joints Under Board-Level Free Fall Drop (BFFD)

2005 ◽  
Author(s):  
Dongji Xie ◽  
David Geiger ◽  
Dongkai Shangguan ◽  
Daniel T. Rooney ◽  
Louis J. Gullo
Keyword(s):  
Failure Modes ◽  
Solder Joints ◽  
Cellular Phone ◽  
Free Fall ◽  
Drop Test ◽  
Strain Level ◽  
Board Structure ◽  
Element Analysis ◽  
Board Level ◽  
The Impact

This paper presented a board-level free fall drop (BFFD) to simulate product free fall drop (PFFD). In BFFD, the board structure is very close to the actual cellular phone boards with similar size. The board edges were reinforced by metal frame and screws similar to the cellular phone housing. The drop test was performed to characterize the solder joints of 0.4mm pitch chip scale package (CSP) packages. To charaterize the stress level, the acceleration was measured and the free drop test was performed for more than 140 boards with different CSP structures. The plastic strain of solder joints in different location was calculated using finite element analysis (FEA). It was found that the strain level is both location and component dependent. This strain level will determine the probability of drop test failure in terms of number of drops to failure. The impact of component type, body size and component location was investigated by both experimentally and FEA. Through drop test, the number of drop before failure (MDBF) were recorded and compared across various CSPs. Failure analysis was also performed to confirm the failure modes.

Trajectory shaping guidance law design using constraint-combining multiplier

2021 ◽  
pp. 095441002098637
Author(s):  
Min-Guk Seo ◽  
Chang-Hun Lee ◽  
Tae-Hun Kim
Keyword(s):  
Design Method ◽  
Impact Angle ◽  
State Variables ◽  
Flight Trajectory ◽  
Potential Significance ◽  
Guidance Law ◽  
Terminal Constraints ◽  
The Impact ◽  
Guidance Laws ◽  
Impact Angle Constraint

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.

scholarly journals The Impact of Narrative Feedback, E-Learning Modules and Realistic Video and the Reduction of Misconception

2021 ◽  
Vol 11 (4) ◽  
pp. 158
Author(s):  
Abdul Halim ◽  
Elmi Mahzum ◽  
Muhammad Yacob ◽  
Irwandi Irwandi ◽  
Lilia Halim
Keyword(s):  
Biology Education ◽  
Free Fall ◽  
Percentage Reduction ◽  
Significant Treatment ◽  
Learning Modules ◽  
Physics Courses ◽  
Learning Platform ◽  
Quasi Experimental ◽  
E Learning ◽  
The Impact

Physics learning in universities utilized the Moodle-based e-learning media as an online learning platform. However, the effectiveness of remediating misconception using online media has not been widely researched. Therefore, this study was set to determine the level of misconception percentage reduction through the use of narrative feedback, the e-learning modules, and realistic video. The study was a quantitative approach with a quasi-experimental method involving 281 students who were taking basic physics courses in the Department of Physics, Chemistry, and Biology Education. The data collection used a three-tier diagnostic test based on e-learning at the beginning of the activity and after the treatment (posttest). The results of the data analysis with descriptive statistics show that the most significant treatment in reducing misconception percentage on the topic of free-fall motion was in the following order: narrative feedback, e-learning modules and realistic video. The misconception percentage reduction in the sub-concept of accelerated free- fall was effective for all types of the treatments.

scholarly journals The effect of heat treatment and impact angle on the erosion behavior of nickel-tungsten carbide cold spray coating using response surface methodology

2021 ◽  
Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi
Keyword(s):  
Heat Treatment ◽  
Response Surface Methodology ◽  
Mass Loss ◽  
Tungsten Carbide ◽  
Response Surface ◽  
Spray Coating ◽  
Impact Angle ◽  
Control Factors ◽  
Heat Treated ◽  
The Impact

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.

Numerical Simulation and Experimental Measurement of a Printed Circuit Board Subjected to Drop Test

2009 ◽  
Vol 419-420 ◽  
pp. 37-40
Author(s):  
Shiuh Chuan Her ◽  
Shien Chin Lan ◽  
Chun Yen Liu ◽  
Bo Ren Yao
Keyword(s):  
Finite Element ◽  
Experimental Measurement ◽  
Test Specimen ◽  
Printed Circuit Board ◽  
Drop Impact ◽  
Simulation Technique ◽  
Drop Test ◽  
Circuit Board ◽  
Printed Circuit ◽  
The Impact

Drop test is one of the common methods for determining the reliability of electronic products under actual transportation conditions. The aim of this study is to develop a reliable drop impact simulation technique. The test specimen of a printed circuit board is clamped at two edges on a test fixture and mounted on the drop test machine platform. The drop table is raised at the height of 50mm and dropped with free fall to impinge four half-spheres of Teflon. One accelerometer is mounted on the center of the specimen to measure the impact pulse. The commercial finite element software ANSYS/LS-DYNA is applied to compute the impact acceleration and dynamic strain on the test specimen during the drop impact. The finite element results are compared to the experimental measurement of acceleration with good correlation between simulation and drop testing. With the accurate simulation technique, one is capable of predicting the impact response and characterizing the failure mode prior to real reliability test.

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