• Title/Summary/Keyword: Weight load

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Evaluation on Structural Safety for Carbon-Epoxy Composite Wing and Tail Planes of the 1.2 Ton Class WIG

  • Park, Hyunbum
    • International Journal of Aerospace System Engineering
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    • v.6 no.1
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    • pp.1-7
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    • 2019
  • In the present study, structural safety and stability on the main wing and tail planes of the 1.2 ton WIG(Wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The carbon-epoxy composite material was used in design of wing structure. The skin-spar with skin-stressed structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, the design load was estimated with maximum flight load. From static strength analysis results using finite element method of the commercial codes. From the stress analysis results of the main wing, it was confirmed that the upper skin structure between the second rib and the third rib was unstable for the buckling load. Therefore in order to solve this problem, three stiffeners at the buckled region were added. After design modification, even though the weight of the wing was a little bit heavier than the target weight, the structural safety and stability was satisfied for design requirements.

Load and Structural Analysis of an Offshore Wind-Turbine Foundation with Weight Control Functionality (자중조절 기능이 있는 해상풍력 지지구조의 하중 및 구조해석)

  • Oh, Minwoo;Kim, Donghyun;Kim, Kiha;Kim, Seoktae
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.3
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    • pp.453-460
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    • 2016
  • Offshore wind turbines are divided into an upper wind turbine and a lower support structure. Offshore wind turbine system is required to secure high reliability for a variety of external environmental conditions compared to ground wind turbines because of additional periodic loads due to ocean wave and current effects. In this study, extreme load analyses have been conducted for the designed offshore wind turbine foundation with weight control functionality using computational fluid dynamics (CFD) then structural analyses have been also conducted to investigate the structural design requirement.

Validation of Urine Volume Evaluation by Hydraulic Pressure Measurement (압력 측정에 의한 요량 계측의 유용성 분석)

  • Kim, Kyung-Ah;Choi, Sung-Soo;Lee, In-Kwang;Park, Kyung-Soon;Kim, Wun-Jae;Lee, Tae-Soo;Cha, Eun-Jong
    • Journal of Biomedical Engineering Research
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    • v.28 no.4
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    • pp.577-584
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    • 2007
  • Uroflowmetry is non-invasive and easily performed to diagnose benign prostatic hypertrophy(BPH) frequent in aged men. Weight change during urination is usually measured to estimate the urinary flow rate by a load cell, but sensitive to any impacts against the bottom of the container, leading to unnecessary noise generation. Moreover, load cells are relatively expensive raising the production cost. The present study proposed a new technique, measuring hydraulic pressure on the bottom of the urine container to evaluate the urinary volume. Low cost pressure transducer enabled almost perfectly linear relationship between the urine volume and the hydraulic pressure. During both the simulated and human urination experiments, variance of the pressure signal was more than 50% smaller than the weight signal acquired by a load cell, which demonstrated that the impact noise was decreased to a great degree by pressure compared to weight measurement.

New uroflowmetry technique measuring hydraulic pressure for prostate diagnostics (전립선 진단을 위한 수압 측정 방식의 새로운 요 유량 계측기법)

  • Kim, Kyung-Ah;Choi, Sung-Soo;Cha, Eun-Jong
    • Journal of Sensor Science and Technology
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    • v.16 no.3
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    • pp.179-186
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    • 2007
  • Uroflowmetry is non-invasive and easily performed to diagnose benign prostate hypertrophy (BPH) frequent in aged men. Weight change during urination is usually measured to estimate the urinary flow rate by a load cell, but sensitive to any impacts against the bottom of the container, leading to unnecessary noise generation. Moreover, load cells are relatively expensive raising the production cost. The present study proposed a new technique, measuring hydraulic pressure on the bottom of the urine container to evaluate the urinary flow rate. Low cost pressure transducer enabled almost perfectly linear relationship between the urine volume and the hydraulic pressure. During both the simulated and human urination experiment, variance of the pressure signal was more than 50 % smaller than the weight signal acquired by a load cell, which demonstrated that the impact noise was decreased to a great degree by pressure compared to weight measurement.

Reinforced concrete beams under drop-weight impact loads

  • May, Ian M.;Chen, Yi;Owen, D. Roger J.;Feng, Y.T.;Thiele, Philip J.
    • Computers and Concrete
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    • v.3 no.2_3
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    • pp.79-90
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    • 2006
  • This paper describes the results of an investigation into high mass-low velocity impact behaviour of reinforced concrete beams. Tests have been conducted on fifteen 2.7 m or 1.5 m span beams under drop-weight loads. A high-speed video camera has been used at rates of up to 4,500 frames per second in order to record the crack formation, propagation, particle spallation and scabbing. In some tests the strain in the reinforcement has been recorded using "Durham" strain gauged bars, a technique developed by Scott and Marchand (2000) in which the strain gauges are embedded in the bars, so that the strains in the reinforcement can be recorded without affecting the bond between the concrete and the reinforcement. The impact force acting on the beams has been measured using a load cell placed within the impactor. A high-speed data logging system has been used to record the impact load, strains, accelerations, etc., so that time histories can be obtained. This research has led to the development of computational techniques based on combined continuum/discontinuum methods (finite/discrete element methods) to permit the simulation of impact loaded reinforced concrete beams. The implementation has been within the software package ELFEN (2004). Beams, similar to those tested, have been analysed using ELFEN a good agreement has been obtained for both the load-time histories and the crack patterns.

Study of the Accelerated Weathering of Sitka spruce under Acidic Conditions (산성(酸性) 조건하(條件下)에서 Sitka spruce의 기상(氣象) 열화(劣化) 가속(加速)에 관(關)한 연구(硏究))

  • Kim, Jae-Jin;Kim, Gyu-Hyeok
    • Journal of the Korean Wood Science and Technology
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    • v.21 no.2
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    • pp.9-14
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    • 1993
  • Weathering of wood in a region of acid rain was performed by the test which thin veneers of Sitka spruce were exposed to outdoor weathering for a total of 18 weeks, with a daily soaking for 30 minutes in acidified water in the pH range 2~5.6. The weathering measured by weight loss and loss in maximum failure load in tension was accelerated by the increase in the acidity of acidified water and in the period of outdoor exposure. It was also shown that the weathering was accelerated even with low acidic conditions in the case of long exposure period, although the weathering was rapidly accelerated with high acidic conditions. When compared the degree of weight loss with that of loss in failure load by weathering, the latter was much greater. From the results of this research, it could be concluded that at pH 4.0 or below of precipitation, the acceleration of weathering of exterior wood would become serious problems, which would be caused deterioration in performance of exterior wood.

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A Review of the Types and Characteristics of Horizontal Load Affecting the Structural Safety of the Lightweight Dry Walls (건식 경량벽체의 구조안전성에 영향을 미치는 수평하중의 종류 및 특성 고찰)

  • Song, Jung-Hyeon;Roh, Yong-Woon;Kin, Ki-Jun;Choi, Soo-Kyung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.43-45
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    • 2013
  • The purpose of this study is to obtain basic data for making performance criteria about the structural safety of lightweight dry wall later by examining types and characteristics of horizontal load acting on the wall. The subjects applying horizontal load to the wall are human and objects. The types of horizontal load are classified as static load and dynamic load depending on the difference of acting time. The magnitude of horizontal load "0.25kN/㎡" defined by KBC 2009 has no significant meaning since it is the unsubstantial nominal load. The result of examining types and characteristics of horizontal load is as follows. (1) Static load by human needs to have more systematic investigation including differences in wall hardness and human weight. (2) Dynamic load by human needs to raise the significance of study result by increasing the number of subjects. (3) Dynamic load by objects needs to accumulate the load specific data for various load subjects considering real situations.

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Development of Onboard Scales to Measure the Weight of Trucks (상용차량의 하중을 측정하기 위한 탑재형 자중계 개발)

  • Seo, Myoung Kook;Shin, Hee Yong;Lee, Ho Yeon;Ko, Jea Il;Tumenjargal, Enkhbaatar
    • Journal of Drive and Control
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    • v.18 no.1
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    • pp.9-16
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    • 2021
  • Overloaded vehicles increase the maintenance cost of road structures, and they are a major factor in causing damage to the roads and bridges. In addition, overloaded vehicles compromise the braking capability of the vehicle; thus, threatening the safety of the driver. In order to prevent overloading of vehicles, the government is cracking down on the roads by using a device that measures the weight of vehicles. But this process is inconvenient because the place where the equipment is installed is far away from where the cargo is loaded. Due to the limitations of these fixed weighing devices, there is a growing need for technology that can monitor vehicle weight distribution and overload conditions in real time. In this work, we develop an onboard scale that can measure the load (weight) of trucks in real time. The onboard scale consists of high sensors, a signal processing unit, and a display, and it measures the load using height-displacement of the vehicle's leaf spring suspension.

Investigation of the Force Transmission Affect by Visual Information and Previous Experience in Virtual Environment (가상환경에서 시각정보와 사전 경험이 힘전달에 미치는 영향에 대한 연구)

  • Lee, JaeHoon;Hwang, HoSung;Yun, WonSik
    • Journal of the Korea Society for Simulation
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    • v.22 no.1
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    • pp.53-61
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    • 2013
  • The purpose of this paper is to examine how the humans learn and perceive the weight of objects corresponding to visual information in virtual environment. We conducted two kinds of load-on-tasks with two virtual objects that have same weight but different visual cues; have same visual cues but changed weight by trails. We found that the subject could not generate appropriate force for the smaller and changed weight objects in the beginning of the trials. the discrepancy between the expected weight and actual force consequences sue to visually invoked size and previous experience made subjects perceive the small object were heavier. one the other hand, after the tasks were repeated, the subject responded the weights were the same or very similar when the mismatch between the expected weight and the actual weight became vanished. this means that the sensorimotor feedback influences the anticipatory control scheme and weight perception aggressively in virtual environment.

A New Load Aggregation Method in Consideration of Non-linear Load (비선형 부하를 고려한 새로운 부하합성 기법)

  • Lee, Jong-Pil;Kim, Sung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.61 no.4
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    • pp.168-173
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    • 2012
  • The aggregation of group loads, which consists of the linear and the non-linear systems, yields the error involved in the reactive power aggregation, which is greater than the active power aggregation in the component based load modeling. Each individual reactive power in a group load affects the aggregated load different from composition rate. This paper proposes a new method that determines the degree of impacts by adjusting the coefficient of weight factors of each load using the least squares error method. The effectiveness of proposed algorithm is demonstrated by simulating three aggregation cases.