Studies on the Impact Structural Damage of Composite Blades

2009 ◽  
pp. 212-212-16
Author(s):  
CT Sun ◽  
RL Sierakowski
Keyword(s):  
Structural Damage ◽  
The Impact ◽  
Composite Blades

Experimental Investigation on Improving Electromechanical Impedance Based Damage Detection by Temperature Compensation

2013 ◽  
Vol 569-570 ◽  
pp. 1132-1139 ◽  
Author(s):  
Thomas Siebel ◽  
Mihail Lilov
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Temperature Compensation ◽  
Impact Damage ◽  
Correlation Coefficients ◽  
Electromechanical Impedance ◽  
Reinforced Plastic ◽  
Influence Of Temperature On ◽  
Compensation Approach ◽  
The Impact

The sensitivity of the electromechanical impedance to structural damage under varying temperature is investigated in this paper. An approach based on maximizing cross-correlation coefficients is used to compensate temperature effects. The experiments are carried out on an air plane conform carbon fiber reinforced plastic (CFRP) panel (500mm x 500mm x 5mm) instrumented with 26 piezoelectric transducers of two different sizes. In a first step, the panel is stepwise subjected to temperatures between-50 °C and 100 °C. The influence of varying temperatures on the measured impedances and the capability of the temperature compensation approach are analyzed. Next, the sensitivity to a 200 J impact damage is analyzed and it is set in relation to the influence of a temperature change. It becomes apparent the impact of the transducer size and location on the quality of the damage detection. The results further indicate a significant influence of temperature on the measured spectra. However, applying the temperature compensation algorithm can reduce the temperature effect at the same time increasing the transducer sensitivity within its measuring area. The paper concludes with a discussion about the trade-off between the sensing area, where damage should be detected, and the temperature range, in which damage within this area can reliably be detected.

scholarly journals Identification of Corrosion on a Hollow Tube Using Vibration

2014 ◽  
Vol 564 ◽  
pp. 176-181
Author(s):  
S.T. Cheng ◽  
Nawal Aswan Abdul Jalil ◽  
Zamir A. Zulkefli
Keyword(s):  
Free Boundary ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Impact Loading ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Localized Corrosion ◽  
Free Boundary Conditions ◽  
The Impact ◽  
Impact Vibration

Vibration based technique have so far been focused on the identification of structural damage. However, not many studies have been conducted on the corrosion identification on pipes. The objective of this paper is to identify corrosion on pipes from vibration measurements. A hollow pipe, 500 mm in length with 63.5 mm in diameter was subjected to impact loading using an impact hammer to identify the natural frequency of the tube in two conditions i) without any corrosion and ii) with an induced localized 40 mm by 40 mm corrosion at the middle of the pipe. The shift of natural frequencies of the structures under free boundary conditions was examined for each node of excitation. The results showed that there is a shift in natural frequency of the pipe, between 3 and 4 Hz near to the corrosion area. It can suggested that that the impact vibration is capable of identifying of localized corrosion on a hollow tube.

Analysis Method for Impact and Dispersion Behavior of Water-Filled Tank

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Hidekazu Takazawa ◽  
Kazuma Hirosaka ◽  
Katsumasa Miyazaki ◽  
Norihide Tohyama ◽  
Naomi Matsumoto
Keyword(s):  
Structural Damage ◽  
Impact Test ◽  
Velocity Ratio ◽  
Research Centre ◽  
Dispersion Pattern ◽  
Test Results ◽  
Analysis Method ◽  
Cylindrical Tank ◽  
Dispersion Behavior ◽  
The Impact

A new Japanese nuclear regulation involves estimating the possible damage to plant structures due to intentional aircraft impact. The effect of aircraft impact needs to be considered in the existing nuclear power plants. The structural damage and fuel dispersion behavior after aircraft impact into plant structures can be evaluated using finite element analysis (FEA). FEA needs validated experimental data to determine the reliability of the results. In this study, an analysis method was validated using a simple model such as a cylindrical tank. Numerical simulations were conducted to evaluate the impact and dispersion behavior of a water-filled cylindrical tank. The simulated results were compared with the test results of the VTT Technical Research Centre of Finland (VTT). The simulations were carried out using a multipurpose FEA code LS-DYNA®. The cylindrical tank was modeled using a shell element, and the tank water was modeled using smoothed particle hydrodynamics (SPH) elements. First, two analysis models were used to evaluate the effect of the number of SPH elements. One had about 300,000 SPH elements and the other had 37,000 SPH elements. The cylindrical tank ruptured in the longitudinal direction after crashing into a rigid wall, and the filled water dispersed. There were few differences in the simulated results when using different numbers of SPH elements. The VTT impact test was simulated with an arbitrary Lagrangian-Eulerian (ALE) element to consider the air drag. The analytical dispersion pattern and history of dispersion velocity ratio agreed well with the impact test results.

scholarly journals Structural Assessment of the Hull Response of an FPSO Unit to Dropped Objects: A Case Study

2019 ◽  
Vol 26 (4) ◽  
pp. 39-46 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Structural Damage ◽  
Local Buckling ◽  
Structural Response ◽  
Offshore Structures ◽  
Mechanical Equipment ◽  
Structural Members ◽  
Impact Area ◽  
Explicit Dynamic ◽  
The Impact

Abstract Offshore structures are exposed to the risk of damage caused by various types of extreme and accidental events, such as fire, explosion, collision, and dropped objects. These events cause structural damage in the impact area, including yielding of materials, local buckling, and in some cases local failure and penetration. The structural response of an FPSO hull subjected to events involving dropped objects is investigated in this study, and non-linear finite element analyses are carried out using an explicit dynamic code written LS-DYNA software. The scenarios involving dropped objects are based on the impact from the fall of a container and rigid mechanical equipment. Impact analyses of the dropped objects demonstrated that even though some structural members were permanently deformed by drop loads, no failure took place in accordance with the plastic strain criteria, as per NORSOK standards. The findings and insights derived from the present study may be informative in the safe design of floating offshore structures.

scholarly journals Preliminary Reconstruction of the November 30, 2007, Chicago, IL Rail Collision

2011 ◽  
Author(s):  
Patricia Llana ◽  
David Tyrell
Keyword(s):  
Field Study ◽  
Preliminary Data ◽  
Structural Damage ◽  
Passenger Train ◽  
Occupant Protection ◽  
Causal Mechanisms ◽  
Occupant Injuries ◽  
The Impact

The Volpe Center is supporting the Federal Railroad Administration in performing rail passenger equipment crashworthiness research. The overall objective of this research is to develop strategies for improving structural crashworthiness and occupant protection. A field study of passenger train accidents is being conducted to investigate the causal mechanisms of the injuries incurred by train occupants. The investigation of the November 30, 2007 collision in Chicago, IL has provided preliminary data on the structural damage as well as occupant injuries resulting from the impact. This data will be used in simulations to guide the development of crashworthiness strategies.

scholarly journals Damage analysis and assessment of the impact of damage on the operation of supporting structures of oil refining tube furnaces

2020 ◽  
Vol 16 (3) ◽  
pp. 193-202
Author(s):  
Alexander V. Golikov ◽  
Dmitry I. Subbotin
Keyword(s):  
Structural Damage ◽  
Spatial Models ◽  
Physical Nature ◽  
Oil Refining ◽  
Main Research ◽  
Software Products ◽  
Tube Furnaces ◽  
Supporting Frame ◽  
The Impact ◽  
Supporting Structures

Relevance. Due to the widespread use in practice, tubular furnaces were chosen as the object of study of this work. The article provides an analysis of damage to the supporting structures of oil refining tubular furnaces. The causes of damage and the physical nature of the development of damage are established. According to the results of field surveys, it was found that about 10% of the furnaces are operated with damage in the form of significant curvature of the supporting structures that developed as a result of the explosion of the gas-air mixture and the technological product inside the furnace space. The aim of the work is to analyze the damage and assess the impact of damage on the operation of the supporting structures of furnaces. Methods. The main research results were obtained by static numerical analysis of spatial models of furnace frameworks in the LIRA-SAPR software package. This complex belongs to the class of software products that implement the finite element method. Results. According to the results of calculating a series of models of structures, the effect of damage on the operation of the supporting structures of the furnace is determined. Based on the analysis of calculation data for models of tube furnaces with damage and comparison of calculation results for furnace models with structural damage identified during the survey, ways to optimize the design decisions of an industrial furnace are determined. Studies have shown the need to improve the design of tube furnaces in the direction of improving technology and improving the structural form of the supporting frame of the furnace.

scholarly journals Large-scale application of the flood damage model RAilway Infrastructure Loss (RAIL)

2016 ◽  
Vol 16 (11) ◽  
pp. 2357-2371 ◽  
Author(s):  
Patric Kellermann ◽  
Christine Schönberger ◽  
Annegret H. Thieken
Keyword(s):  
Risk Management ◽  
Risk Aversion ◽  
Flood Risk ◽  
Structural Damage ◽  
Large Scale ◽  
Damage Model ◽  
Flood Damage ◽  
Railway Infrastructure ◽  
Increased Risk ◽  
The Impact

Abstract. Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than EUR 100 million due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate (1) the expected structural flood damage and (2) the resulting repair costs of railway infrastructure due to a 30-, 100- and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.

The Impact of Hurricane Maria on Individuals Living with Non-Communicable Disease in Puerto Rico: The experience of 10 communities

2021 ◽  
Author(s):  
Elizabeth L. Andrade ◽  
Amalis Cordova Mustafa ◽  
Courtney Riggle-vanSchagen ◽  
Megan Jula ◽  
Carlos E. Rodriguez-Diaz ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Natural Hazards ◽  
Structural Damage ◽  
Communicable Disease ◽  
Community Level ◽  
Morbidity And Mortality ◽  
Health Concern ◽  
Increased Risk ◽  
The Impact ◽  
Non Communicable Disease

Abstract Background Coinciding with the rising non-communicable disease (NCD) prevalence worldwide is the increasing frequency and severity of natural hazards. Protecting populations with NCDs against natural hazards is ever more pressing given their increased risk of morbidity and mortality in disaster contexts. Methods This investigation examined Hurricane Maria’s impact across 10 communities in Puerto Rico to determine whether and how disaster impact and community attributes affected NCD management. We conducted 40 qualitative interviews with mayors, first responders, faith leaders, community leaders, and municipal employees, with 4 interviews per selected municipality. Using QSR NVivo software, we coded interview transcripts and created categorical community-level impact variables based on participant responses. We undertook thematic analysis to characterize community-level impact and consequences for NCD management, and to identify convergent and divergent themes. Using a matrix coding query, we compared NCD management experiences across communities by impact variables and community attributes. Results The delivery of healthcare, pharmacy, and dialysis services was compromised due to facility structural damage and ineffective contingencies for electrical power and water supply. The challenges resulting from power outages were immediate, and individuals who were reliant on life-sustaining medical equipment, dialysis, or the refrigeration of medications were most vulnerable. Inaccessible roadways and the need to travel greater distances to locate operational health services were major impediments to transporting patients in need of NCD care, with those requiring dialysis and living in remote, mountainous communities at highest risk due to landslides and lengthy roadway obstruction. These barriers were compounded by limited communication to locate services and coordinate care. Two weeks post-hurricane, emerging challenges to NCD management included widespread diesel fuel shortages for generators, and shortages in medications, oxygen, and medical supplies. In the weeks to months post-hurricane, the emergence or exacerbation of mental health disorders was characterized as a pressing health concern. Conclusions Study findings identify contributors to morbidity and mortality among individuals with NCDs following Hurricane Maria. The degree to which these impacts were experienced across communities with different characteristics is discussed, offering important lessons regarding the impact of catastrophic disasters on NCD management for improve community disaster resilience.

scholarly journals Is the Viscoelastic Sheet for Slamming Impact Ready to Be Used on Glass Fiber Reinforced Plastic Planning Hull?

2020 ◽  
Vol 10 (18) ◽  
pp. 6557 ◽  
Author(s):  
Patrick Townsend ◽  
Juan Carlos Suárez Bermejo ◽  
Paz Pinilla ◽  
Nadia Muñoz
Keyword(s):  
Structural Damage ◽  
High Speed ◽  
Damage Threshold ◽  
Fluorescent Light ◽  
Glass Fiber Reinforced Plastic ◽  
Additional Layer ◽  
Glass Fiber Reinforced ◽  
Weight Drop ◽  
Viscoelastic Layers ◽  
The Impact

Planing hull vessel built with polymer matrix laminates and fiberglass reinforcements (GFRP) suffer structural damage due to the phenomenon of slamming during navigation, due to the impact of the boat hull on the free surface of the water at high speed. A modification in the manufacture of the laminates for these fast boats is proposed, consisting of the insertion of an additional layer of a hybrid material, formed by elastomer encapsulated in an ABS polymer cell. Using GFRP specimens made from pre-impregnated material and reproducing the characteristic impacts of slamming, it is possible to compare the modified material with the introduction of the viscoelastic layers with the response under the same conditions as the unmodified laminates. Additionally, the panels have been tested using impacts due to weight drop at different energies, which allow determining the material damage threshold as a function of the energy absorbed, and to establish a comparison with the GFRP panels modified by observation in fluorescent light. It is verified that the proposal to reduce the effect of these impacts on the generation of damage to the material and its progression throughout the service life of the vessel is effective.

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