Comparing Shock, Random and Sine Vibration Loads of the Electronic Equipment

2005 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Dynamic Load ◽  
Random Vibration ◽  
Sine Wave ◽  
Electronic Equipment ◽  
Dynamic Loads ◽  
Peak Acceleration ◽  
Maximum Acceleration ◽  
Dynamic Excitations ◽  
Dynamic Damage ◽  
Resonant Point

It is a challenge to correlate different dynamic loads. Often, attempts are made to compare the peak acceleration of sine wave to the root mean square (RMS) acceleration of random vibration and shock. However, peak sine acceleration is the maximum acceleration at one frequency. Random RMS is the square root of the area under a spectral density curve. These are not equivalent. This paper is to discuss a mathematical method to compare different kinds of dynamic damage at the resonant point of the related electronic equipment. The electronic equipment will vibrate at its resonance point when there are dynamic excitations. The alternative excitation at the resonant frequency causes the most damage. This paper uses this theory to develop a method to correlate different dynamic load conditions for electronic equipment. The theory is that if one kind of dynamic load causes the same levels of damaging effects as the other, the levels of vibration can then be related.

Study of Printed Circuit Board Shock Transmissibility

2007 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Dynamic Loads ◽  
Shock Load ◽  
Load Factor ◽  
Peak Acceleration ◽  
Maximum Acceleration ◽  
Resonance Point ◽  
Printed Circuit ◽  
Dynamic Excitations

It is always a challenge to deal with dynamic loads. Often, attempts are made to compare the peak acceleration of the shock load. However, the peak acceleration is the maximum acceleration at one frequency. It may not be the most damaging load for the electronics with a different resonant frequency. This paper is to propose a mathematical method to calculate printed circuit board deflections under shock load. The theory is the printed circuit board will deflect the most at its resonance point when there are dynamic excitations. This paper also discusses a method to use load factor or equivalent acceleration load to calculate printed circuit board deflections under dynamic loads.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

scholarly journals ANALYSIS OF DYNAMIC LOADING OF IMPROVED CONSTRUCTION OF A TANK CONTAINER UNDER OPERATIONAL LOAD MODES

2019 ◽  
Vol 2 ◽  
pp. 61-70
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Oleksandr Gorobchenko ◽  
Serhii Turpak ◽  
Iryna Kyrychenko ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Dynamic Load ◽  
Operating Conditions ◽  
Dynamic Loads ◽  
The Finite Element Method ◽  
Operational Load ◽  
International Transport ◽  
Improvement Measures ◽  
Cargo Transportation

An increase in the volume of bulk cargo transportation through international transport corridors necessitates the commissioning of tank containers. Intermodalization of a tank container predetermines its load in various operating conditions depending on the type of vehicle on which it is carried: aviation, sea, air or rail. The analysis of the operating conditions of tank containers, as well as the regulatory documents governing their workload, led to the conclusion that the most dynamic loads acting on the supporting structures during transportation by rail. Namely, during the maneuvering collision of a wagon-platform, on which there are tank containers. In this case, it is stipulated that for a loaded tank container, the dynamic load is assumed to be 4g, and for an empty (for the purpose of checking the reinforcement) – 5g. It is important to note that when the tank container is underfilled with bulk cargo and taking into account movements of fittings relative to fittings, the maximum value of dynamic load can reach significantly larger values. Therefore, in order to ensure the strength of tank containers, an improvement of their structures has been proposed by introducing elastic-viscous bonds into the fittings. To determine the dynamic loading of the tank container, taking into account the improvement measures, mathematical models have been compiled, taking into account the presence of elastic, viscous and elastic-viscous bonds between the fittings, stops and fittings. It is established that the elastic bond does not fully compensate for the dynamic loads acting on the tank container. The results of mathematical modeling of dynamic loading, taking into account the presence of viscous and elastic-viscous coupling in the fittings, made it possible to conclude that the maximum accelerations per tank container do not exceed the normalized values. The determination of the dynamic loading of the tank container is also carried out by computer simulation using the finite element method. The calculation takes place in the software package CosmosWorks. The maximum values of accelerations are obtained, as well as their distribution fields relative to the supporting structure of the tank container. The developed models are verified by the Fisher criterion. The research will contribute to the creation of tank containers with improved technical, operational, as well as environmental characteristics and an increase in the efficiency of the liquid cargo transportation process through international transport corridors.

scholarly journals The behaviour of roof gable walls under the effect of earthquake load

2010 ◽  
Vol 10 (2) ◽  
pp. 251-263 ◽  
Author(s):  
M. Kamanli ◽  
F. S. Balik
Keyword(s):  
Dynamic Load ◽  
Shaking Table ◽  
Dynamic Loads ◽  
Roof System ◽  
Earthquake Loads ◽  
Research Department ◽  
Earthquake Research ◽  
Earthquake Load

Abstract. In this study, the effect of earthquake loads on roof gable walls and the behaviours of these roof gable walls are investigated. In preparation of the study, two experiments on cradle roof system which gets and does not get any loads off the roof members were carried out in all. The experiments were performed on the shaking table in Earthquake Research Department of General Directorate of Disaster Affairs. Through the experiments, some considerable results were obtained on the behaviours of roof gable walls under the effect of horizontal dynamic loads. The results obtained at the end of these examinations are given and discussed. Furthermore, suggestions to make the brick gable walls more reliable against the loads of earthquake are given. When the results of the experiments were generally taken into consideration, it was realized that the gable walls in both roof systems would partly or completely collapse even under the effect of a little horizontal dynamic load.

scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

scholarly journals Development of Real-Time Measurement Platform for Stretchable and Rollable Functions of Flexible Electronics under Multiple Dynamic Loads

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 106
Author(s):  
Chang-Chun Lee ◽  
Jui-Chang Chuang ◽  
Ruei-Ci Shih ◽  
Chi-Wei Wang
Keyword(s):  
Flexible Electronics ◽  
Electronic Devices ◽  
Sine Wave ◽  
Wearable Devices ◽  
Dynamic Loads ◽  
Inspection System ◽  
Mechanical Reliability ◽  
Electronic Components ◽  
Real Time Measurement ◽  
Applied Fields

Mainstream next generation electronic devices with miniaturized structures and high levels of performance are needed to meet the characteristic requirements of electronics with flexible and stretchable capabilities. Accordingly, several applied fields of innovative electronic component techniques, such as wearable devices, foldable curtain-like displays, and flexible hybrid electronic (FHE) biosensors, are considered. This study presents a novel inspection system with multifunctions of stressing tensile and bending mechanical loads to acquire the stretchable and rollable characteristics of soft specimens. The performance of the proposed measurement platform using samples of three different geometric types is evaluated in terms of its stretchability. The results show a remarkable enhancement of mechanical reliability when the sine wave geometric structure is used. A symmetrical sine wave-shaped sample is designed to measure performance under cyclic rolling. The proposed measurement platform of flexible electronics meets the testing requirements of mechanical reliability for the development of future flexible electronic components and FHE products.

Study on Dynamic Response of Hollow Pile Using the Method of Composite Stiffness Principle and Biparameter

2011 ◽  
Vol 243-249 ◽  
pp. 2679-2683
Author(s):  
Yong Mou Zhang ◽  
Min Yang ◽  
Qiang Gang Yan
Keyword(s):  
Dynamic Load ◽  
Bending Moment ◽  
Dynamic Loads ◽  
Concrete Pile ◽  
Side Resistance ◽  
Geological Conditions ◽  
Internal Forces ◽  
The Finite Difference Method ◽  
Composite Stiffness ◽  
Laterally Loaded

The method of composite stiffness principle and biparameter for laterally loaded pile was used in this paper to calculate the amplitude of deflection and rotation of pile on the ground when the vibration frequency of dynamic load is equal to or close to the natural frequency of pile, i.e. when the pile is in the state of resonance. And the amplitude of the maximum bending moment and its location was also calculated. Then the finite difference method which is simple in principle and easy to program was used to calculate the displacement, soil side resistance and internal forces of pile under horizontal dynamic load. By choosing reasonable parameters, rotation, displacement, and the maximum bending moment of hollow concrete pile and solid pile under the same dynamic loads at pile top in the same geological conditions were calculated respectively. On this basis, the performance differences between hollow pile and solid pile were analyzed. Some advantages of hollow pile were obtained. This research provides a theoretical guidance for the using of hollow pile in engineering.

scholarly journals Dynamic loads in self-aligning gear transmissions of heavy loaded machines

2021 ◽  
pp. 84-90
Author(s):  
B. V. Vinogradov ◽  
D. O. Fedin ◽  
V. I. Samusia ◽  
D. L. Kolosov
Keyword(s):  
Relative Motion ◽  
Dynamic Load ◽  
Ball Mill ◽  
Rigid Body Dynamics ◽  
Gear Transmission ◽  
Dynamic Loads ◽  
Load Factor ◽  
Misalignment Angle ◽  
Drive Gear ◽  
Ball Mills

Purpose. Development of a mathematical model of a heavy loaded gear transmission with a self-aligning drive gear; evaluation of the dynamic load on the gear transmission in the gear alignment process. Methodology. The calculation schematic and equations of the relative motion of the self-aligning drive gear are formed using the methods of rigid body dynamics. Analytical expressions for the gear self-alignment time, collision velocity during the alignment and dynamic load factor are obtained by integrating an ordinary differential equation. Methods of the linear theory for oscillations are used to determine the dynamic factor. Findings. The article investigates the state-of-art design and mathematical models of the self-aligning gear. An equation for the relative motion of the moving part of the gear has been formed using the methods of rigid body dynamics. It is shown that by using the proposed hypotheses, the movement of the gear can be reduced to rotation about the instantaneous axis. The influence of geometric and dynamic parameters of the ball mill drive on dynamic loads in the open gear transmission is investigated. The gear alignment speed dependences on the tooth mesh misalignment angle in the gear transmission and the inertial parameters of the gear have been obtained. The obtained dependencies were used to calculate the time and speed of the gear alignment in the open gear transmission of the ball mill 5.5 6.5 (central discharge ball mill). It is shown that in the real range of mesh misalignment angles and gear parameters, the time of the gear alignment is several orders of magnitude less than the time of teeth re-engagement. In the presence of the variable component of the mesh misalignment angle, the gear will constantly make a relative motion with strikes; depending on the current value of the mesh misalignment angle, the dynamic load on the gear transmission can be significant. It is shown that when assessing the efficacy of self-aligning gears, it is necessary to take into account a possible increase in dynamic loads. The dynamic factor and the load factor are calculated for the nominal value of the mesh misalignment angle in the open gear transmission of 5.5 6.5 ball mills. Originality. A mathematical model of the dynamics of a self-aligning gear transmission in heavy duty machine drives has been developed. A quantitative assessment of internal dynamic load factor in an open gear transmission of 5.5 6.5 ball mills has been carried out. Practical value. A method for determining the dynamic component of the load on a gear transmission containing a self-aligning drive gear has been developed.

scholarly journals STATIC AND DYNAMIC LOADS ON THE BOTTOM ROW OF ARMOUR UNITS: A THEORETICAL AND PHYSICAL MODEL STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 44
Author(s):  
Michael Alexander Van de Koppel ◽  
Michiel Muilwijk ◽  
Henk Jan Verhagen
Keyword(s):  
Physical Model ◽  
Dynamic Load ◽  
Packing Density ◽  
Single Layer ◽  
Dynamic Loads ◽  
Model Study ◽  
Static And Dynamic Loads

A physical model study on the row averaged static and dynamic load on the bottom row of single layer armour units in order to investigate the influence of various parameters such as the number of rows on the slope of a breakwater and the initial relative packing density.

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