scholarly journals Assessment of Structural Performance and Integrity for Vibration-based Energy Harvester in Frequency Domain

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 357
Author(s):  
Ji-Won Jin ◽  
Ki-Weon Kang
Keyword(s):  
Frequency Domain ◽  
Natural Frequency ◽  
Production Efficiency ◽  
Performance Test ◽  
Energy Harvester ◽  
Structural Integrity ◽  
Structural Response ◽  
Structural Performance ◽  
Railway Vehicle ◽  
Response Analysis

A vibration-based energy harvester (VEH) utilizes vibrations originated from various structures and specifically maximizes the displacement of its moving parts, using the resonance between the frequency of external vibration loads from the structure and the natural frequency of VEH to improve power production efficiency. This study presents the procedure to evaluate the structural performance and structural integrity of VEH utilized in a railway vehicle under frequency domain. First of all, a structural performance test was performed to identify the natural frequency and assess the structural response in frequency domain. Then, the static structural analysis was carried out using FE analysis to investigate the failure critical locations (FCLs) and effect of resonance. Finally, we conducted a frequency response analysis to identify the structural response and investigate the structural integrity in frequency domain. Based on these results, the authors assessed the structural performance and integrity of VEHs in two versions.

scholarly journals Structural Performance Evaluation for Vibration-based Energy Harvester utilized in Railway Vehicle

2018 ◽  
Vol 167 ◽  
pp. 02003
Author(s):  
Ki-Weon Kang ◽  
Ji-Won Jin
Keyword(s):  
Performance Test ◽  
Energy Harvester ◽  
Structural Integrity ◽  
Structural Response ◽  
Structural Performance ◽  
Railway Vehicle ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Element Analysis ◽  
Vibration Energy Harvester

This study aims to assess the structural performance and structural integrity of vibration energy harvester (VEH). For this, the structural performance test were conducted to identify the natural frequency and structural response against frequency. And then, static structural analysis was performed using finite element analysis to investigate the failure critical locations (FCLs). Finally, we conducted the frequency response analysis in frequency domain to obtain the structural response with frequency and investigate the structural integrity of VEH. Using the above results, we assessed the structural performance and structural integrity of two types of VEHs.

Engineering Criticality Assessments of Floating Offshore Platforms Based on Time Domain Structural Response Analysis

2021 ◽  
Author(s):  
Jeffrey O’Donnell ◽  
Johyun Kyoung ◽  
Sagar Samaria ◽  
Anil Sablok
Keyword(s):  
Fracture Mechanics ◽  
Time Domain ◽  
Structural Integrity ◽  
Structural Response ◽  
Life Extension ◽  
Response Analysis ◽  
Offshore Platforms ◽  
Industry Standards ◽  
Offshore Industry ◽  
Integrity Assessments

Abstract This paper presents a time-domain S-N fatigue analysis and an approach to reliable and robust engineering criticality assessments to supplement or provide an alternative to S-N fatigue assessments of offshore platform structures based on time domain structural response analysis. It also provides recommendations for industry standards to improve guidance for structural integrity assessments of offshore platforms using fracture mechanics. Demand continues to grow in the offshore industry to attain value from captured operational data for a number of purposes, including the reduction of uncertainties in structural integrity assessments during design and over the operational lifetime of floating offshore platforms. Recent advances in time domain structural analysis technology demonstrate substantially more accurate assessments of non-linear platform loadings and responses with enhanced computational efficiency. The current S-N approach for fatigue design and integrity assessments calculates a fatigue damage factor that does not address how loading occurs over time (ABS, DNVGL-RP-C203). For the present study, engineering criticality assessments (ECAs) based on fracture mechanics theory (BS 7910) are applied utilizing time-domain loading information theory. The ECA returns the smallest initial flaws that can grow to a critical size during a design lifetime, which can serve as an indicator of acceptability during design, a technical basis for in-service inspection intervals and facilitates asset integrity and life extension assessments. Critical initial flaws are calculated using the Paris Law (BS 7910) and cumulative fatigue crack growth in two ways: with and without an integrated and consistent check for fracture instability. The results are compared with those from S-N fatigue analyses and recommendations are provided.

Engineering Studies on Joint Bar Integrity: Part II — Finite Element Analyses

2014 ◽  
Author(s):  
Michael E. Carolan ◽  
David Y. Jeong ◽  
A. Benjamin Perlman
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Structural Response ◽  
Relative Effect ◽  
Structural Performance ◽  
Finite Element Analyses ◽  
Field Surveys ◽  
Engineering Studies ◽  
Toe Angle ◽  
Support Conditions

This paper is the second in a two-part series describing research sponsored by the Federal Railroad Administration (FRA) to study the structural integrity of joint bars. In Part I, observations from field surveys of joint bar inspections conducted on revenue service track were presented [1]. In this paper, finite element analyses are described to examine the structural performance of rail joints under various loading and tie-ballast support conditions. The primary purpose of these analyses is to help interpret and understand the observations from the field surveys. Moreover, the finite element analyses described in this paper are applied to conduct comparative studies and to assess the relative effect of various factors on the structural response of jointed rail to applied loads. Such factors include: discrete tie support (i.e. supported joint versus suspended joint with varying spans between effective ties), bolt pattern (four versus six bolts), initial bolt tension, and easement. In addition, results are shown for 90 lb rail joined with long-toe angle bars compared to 136 lb rail joined with standard short-toe joint bars.

Effect of Internal Pressure on Free Spanning Pipelines

2010 ◽  
Author(s):  
Olav Fyrileiv
Keyword(s):  
Internal Pressure ◽  
Natural Frequency ◽  
Structural Integrity ◽  
State Of The Art ◽  
Structural Response ◽  
Design Codes ◽  
Submarine Pipeline ◽  
Water Flow Velocity ◽  
Intervention Costs ◽  
Pipeline Design

Free span assessment has more and more become an important part of modern pipeline design. The reason for this is partly that the remaining hydrocarbon reservoirs are located in more challenging places, e.g. with very uneven seabed. Another explanation is that the pipeline design codes a few decades ago did not allow for vibrating free spans, while the modern, state-of-the-art pipeline codes, such as DNV-OS-F101 “Submarine Pipeline Systems” (2007) [1] and its Recommended Practices, opens for long spans that are allowed to vibrate as long as the structural integrity is ensured. By opening for longer free spans significant seabed intervention costs associated with trenching, rock dumping and supporting spans by other means are saved. One of the governing parameters to ensure the structural integrity of free spans is the natural frequency of the span. This is a parameter that the designer can to some degree control by means of moderate seabed intervention, e.g. span support. Since the natural frequency of the span together with the water flow velocity normal to the span determine the vibrations and the cyclic loading it is of vital importance to be able to estimate a realistic value of this frequency. The natural frequency is influenced by several effects. One of them is the effect of the internal pressure. This may represent a challenge since the effect of the pressure is the opposite of what one instantaneously thinks is correct. Quite recently some discussion about the effect of internal pressure on free spans were raised and some experimental data presented that claimed to prove that the way the internal pressure was handled in the DNV-RP-F105 “Free Spanning Pipelines” (2006) [2] is wrong. The intention of this paper is to show how the internal pressure influences on the structural response of free spans, and that the DNV codes and standard non-linear FE software, e.g. Abaqus, handle this effect in an adequate manner.

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

Debonding Behaviors of CFRP Strengthened RC Beams with Weak Interfaces

2013 ◽  
Vol 351-352 ◽  
pp. 587-591
Author(s):  
Sen Li ◽  
Xiao Gang Wang ◽  
Xin Gang Zhou
Keyword(s):  
Tensile Strain ◽  
Structural Integrity ◽  
Structural Performance ◽  
Rc Beams ◽  
Test Results ◽  
Weak Interface ◽  
Premature Rupture ◽  
Loading Process ◽  
Interface Effects

Debonding behaviors of CFRP strengthened RC beams were experimentally investigated under the influence of weak interfaces, which are induced either by defective bonding of replaced cover or expansive cracks. Shown by test results, weak interfaces impaired considerably the structural integrity of strengthening systems during loading, and easily led to CFRP debonding failure. U-strips worked effectively in preventing the integral debonding and guarantee the structural performance of flexural sheets. However, local cover delamination in the loading process and premature rupture of flexural CFRP could still take place due to the weak interface effects. Therefore, allowable tensile strain of flexural CFRP should be reduced, and more strict confinement and anchorage measures should be taken in this case.

The Finite Element Analysis and Optimization for the Grinder Based on the Joint Surface

2013 ◽  
Vol 281 ◽  
pp. 165-169 ◽  
Author(s):  
Xiang Lei Zhang ◽  
Bin Yao ◽  
Wen Chang Zhao ◽  
Ou Yang Kun ◽  
Bo Shi Yao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Joint Surface ◽  
Weak Links ◽  
Response Analysis ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Harmonic Response Analysis ◽  
Grinding Machine

Establish the finite element model for high precision grinding machine which takes joint surface into consideration and then carrys out the static and dynamic analysis of the grinder. After the static analysis, modal analysis and harmonic response analysis, the displacement deformation, stress, natural frequency and vibration mode could be found, which also helps find the weak links out. The improvement scheme which aims to increase the stiffness and precision of the whole machine has proposed to efficiently optimize the grinder. And the first natural frequency of the optimized grinder has increased by 68.19%.

A Novel Solution to Compute Stress Time Series in Nonlinear Hydro-Structure Simulations

2015 ◽  
Author(s):  
Fabien Bigot ◽  
François-Xavier Sireta ◽  
Eric Baudin ◽  
Quentin Derbanne ◽  
Etienne Tiphine ◽  
...  
Keyword(s):  
Time Series ◽  
Frequency Domain ◽  
Time Domain ◽  
Hot Spot ◽  
Structural Response ◽  
Container Ship ◽  
Time Step ◽  
Computation Cost ◽  
Hull Girder ◽  
Non Linear

Ship transport is growing up rapidly, leading to ships size increase, and particularly for container ships. The last generation of Container Ship is now called Ultra Large Container Ship (ULCS). Due to their increasing sizes they are more flexible and more prone to wave induced vibrations of their hull girder: springing and whipping. The subsequent increase of the structure fatigue damage needs to be evaluated at the design stage, thus pushing the development of hydro-elastic simulation models. Spectral fatigue analysis including the first order springing can be done at a reasonable computational cost since the coupling between the sea-keeping and the Finite Element Method (FEM) structural analysis is performed in frequency domain. On the opposite, the simulation of non-linear phenomena (Non linear springing, whipping) has to be done in time domain, which dramatically increases the computation cost. In the context of ULCS, because of hull girder torsion and structural discontinuities, the hot spot stress time series that are required for fatigue analysis cannot be simply obtained from the hull girder loads in way of the detail. On the other hand, the computation cost to perform a FEM analysis at each time step is too high, so alternative solutions are necessary. In this paper a new solution is proposed, that is derived from a method for the efficient conversion of full scale strain measurements into internal loads. In this context, the process is reversed so that the stresses in the structural details are derived from the internal loads computed by the sea-keeping program. First, a base of distortion modes is built using a structural model of the ship. An original method to build this base using the structural response to wave loading is proposed. Then a conversion matrix is used to project the computed internal loads values on the distortion modes base, and the hot spot stresses are obtained by recombination of their modal values. The Moore-Penrose pseudo-inverse is used to minimize the error. In a first step, the conversion procedure is established and validated using the frequency domain hydro-structure model of a ULCS. Then the method is applied to a non-linear time domain simulation for which the structural response has actually been computed at each time step in order to have a reference stress signal, in order to prove its efficiency.

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