• Advances in concrete construction
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• 제10권2호
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• pp.161-169
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• 2020

This paper studies the influence of silica fume and Processed Quarry Fines (PQF) on the flexural behaviour of the reinforced concrete beams by experimental as well as numerical studies. The study has been shown that the incorporation of PQF can significantly increase the stiffness and the flexural strength of reinforced HPC beams. Also, the ultimate strength of specimens prepared with the 10% silica fume and 100% PQF are higher compared to conventional reinforced concrete specimen. Numerical analysis is performed to find the ultimate strength of HPC beams to compare with experimental results. Nonlinear behaviour of steel reinforcing bars and plain concrete is simulated using appropriate constitutive models and experimental results. The results indicate that the ultimate strength, deformed shape and crack patterns of reinforced HPC beams obtained through the Finite Element Analysis (FEA) are confirming with the experimental results.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권1호
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• pp.29-39
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• 2000

A series of tests were performed to verify the transient characteristics of heat pump in heating and cooling mode when operating speed was varied over the 30 to 102Hz. One of the major issues that has not been addressed so far is transient characteristics during speed modulation. The model for cycle simulation has been developed to predict the cycle performance under conditions of decreasing drive frequency and the results of the theoretical study were compared with the results of the experimental study. The simulated results were in good agreement with the experimental result within 10%. The transient cycle migration of the liquid state refrigerant causes significant dynamic change in system. Thus, the migration of refrigerant was the most important factor whenever do experimental results analysis or develop simulation model.

• Steel and Composite Structures
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• 제12권6호
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• pp.465-489
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• 2012

Residual stresses play important role for design of steel structural members. Cold formed sections usually have residual stresses caused by roll forming. When compared to stresses caused by the working load, especially for compressed members, the effects of residual stresses can be favorable or unfavorable depending on magnitude, orientation and distribution of these stresses. The research presented in this paper includes experimental investigations of residual stresses, initial imperfections and material properties on cold formed carbon steel open cross sections. Experimental results have been compared to results obtained in similar tests with stainless and high strength steel cross sections. Theoretical and experimental research, conducted for cold formed open cross sections, are important for design of axially compressed members. This paper presents two methods of residual stresses investigation: magnetic method and method of pre-drilled holes and obtained results have been compared with results of residual stresses from other authors.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.307-310
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• 2004

The paper presents the numerical and experimental results for the dynamic response vibration of a cantilevered beam subjected to a moving mass with variable speeds. Governing equations of motion under a moving mass were derived by Galerkin's mode summation method taking into account the effects of all forces due to moving mass, and the numerical results were calculated by Runge-Kutta integration method. The effects of the speed, acceleration and the magnitude of the moving mass on the response of the beam are fully investigated. In order to verify numerical results, some experiments were conducted, and the numerical results have a little difference with the experimental ones.

• Advances in aircraft and spacecraft science
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• 제4권2호
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• pp.125-144
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• 2017

This paper summarises the design of a gust generator and the comparison between high fidelity numerical results and experimental results. The gust generator has been designed for a low subsonic wind tunnel in order to perform gust response experiments on wings and assess load alleviation. Special attention has been given to the different design parameters that influence the shape of the gust velocity profile by means of CFD simulations. Design parameters include frequency of actuation, flow speed, maximum deflection, chord length and gust vane spacing. The numerical results are compared to experimental results obtained using a hot-wire anemometer and flow visualisation by means of a tuft and smoke. The first assessment of the performance of the gust generator showed proper operation of the gust generator across the entire range of interest.

• 한국정밀공학회지
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• 제29권2호
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• pp.208-213
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• 2012

In this study, the mechanical joint performance of the V-Insert clamp applied to automobile exhaust pipes was evaluated through the experimental investigation of its axial load capacity. The axial load of the V-Insert clamp was also determined by using theoretical equations presented by Shoghi and compared with the experimental results. As results of the theoretical prediction, the axial load of the V-Insert clamp tended to increase along with smaller angle of the V-Insert segment and the lower friction coefficient between the V-Insert segment and exhaust pipes. The experimental results under tightening effects were similar to the theoretical results and the axial load of the V-Insert clamp presented maximum values in the range of all torques at distance of 2mm between each exhaust pipes. The experimental results under loading effects were similar to the theoretical results in the range of lower torques but deviated from the theoretical results in the range of higher torques. These results would be beneficial to improve the joint and sealing performance of the V-Insert clamp.

• Structural Monitoring and Maintenance
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• 제5권3호
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• pp.345-361
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• 2018

The set of processes performed to determine the dynamic characteristics of the constructed structures is named experimental modal analysis. Using experimental modal analysis and interpreting its results, structural failure can be assessed and then it would be possible to plan for their repair and maintenance. The purpose of the experimental modal analysis is to determine the resonance frequencies, mode shapes and Mode damping for the structure. Diverse methods for determining the shape of the mode by various researchers have been presented. There are pros and cons for each of these methods. This paper presents a method for determining the mode shape of the structures using the response spectrum in the experimental modal analysis. In the first part, the principles of the proposed method are described. Then, to check the accuracy of the results obtained from the proposed method, single and multiple degrees of freedom models were numerically and experimentally investigated.

• 한국소음진동공학회논문집
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• 제11권4호
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• pp.43-51
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• 2001

An experimental modal analysis is the process to identify structure's dynamic characteristics such as resonant frequencies, damping values and mode shapes. An experimental model was made of stainless steel in the shape of a circular cylindrical shell and installed on the test bed with jigs. For investigating vibrational characteristics of the continuous circular cylindrical shell with intermediate supports, modal testing is performed by using impact hammer, accelerometer and 8-channel FFT analyzer. The frequency response function(FRF) measurements are also made on the experimental model within the frequency range from 0 to 4kHz. Modal parameters are identified from resonant peaks in the FRF's and animated deformation patterns associated with each of the resonances are shown on a computer screen. The experimental results are compared with analytical and FEA results.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.199-208
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• 2011

This work presents numerical results, using OpenFOAM, of the flow in the swirl flow generator test rig developed at Politehnica University of Timisoara, Romania. The work shows results computed by solving the unsteady Reynolds Averaged Navier Stokes equations. The unsteady method couples the rotating and stationary parts using a sliding grid interface based on a GGI formulation. Turbulence is modeled using the standard k-${\varepsilon}$ model, and block structured wall function ICEM-Hexa meshes are used. The numerical results are validated against experimental LDV results, and against design velocity profiles. The investigation shows that OpenFOAM gives results that are comparable to the experimental and design profiles. The unsteady pressure fluctuations at four different positions in the draft tube is recorded. A Fourier analysis of the numerical results is compared whit that of the experimental values. The amplitude and frequency predicted by the numerical simulation are comparable to those given by the experimental results, though slightly over estimated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1631-1636
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• 2003

The purpose of this study is to analyze the phenomena of the thermally-induced vibration for the flexible space structure due to abrupt change of radiation heating circumstance using the numerical analyze and experiment test. In order to verify this structure, numerical approaches on the simplified flexible tube were compared with experimental test results at the ground experimental facility In this analyze, it was found that the thermal deformation occurs firstly due to fast radiation heating of flexible structure and then the thermally-induced vibration would be induced due to small periodic change of temperature. According to comparison of numerical and experimental result, in case of no tip mass, the first mode vibration by the numerical analyze was O.78Hz same as that of the experimental result However in case of increase tip-masses of 8g l6g, 50g and 100g, the first modes vibration theoretical analyze were 1.75Hz, 1.3Hz, 0.87Hz and O.73Hz, in decrease trend respectively and those by experimental test were 234Hz, 1.5Hz, O.78Hz and O.78Hz in decrease trend respectively Although using the simpled equation for the estimation, the estimation results were similar to experimental results.