• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.107-115
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• 2001

It is required more precise analysis for practical load because of complexities and varieties of vehicle structure. To establish the numerical model, many researchers have been developed designing tools for linking F.E. Analysis results and experimental results. There studies have generally focused on each experimental method or analytical method separately. There are few studies based on both methods. This paper conceives new procedure for the determination of the load direction and magnitude applied on mechanical structures. New procedure is the combination of the analytical and empirical method with analyzed strain by F.E. Analysis under unit load and with measured principal stress by strain gages under driving load, respectively. In this paper, we theorize the procedure of practical load determination and make the validity and the practicality of the procedure with the application to T-shape jointed structure. F.E. Analysis is conducted to get the principal stress on arbitrary points in the F.E. model of T-shape joint under unit load. Then experiment is carried out to get the principal stress on the same points of F.E. model. To demonstrate the actual driving condition, the load conditions are bending and torsion. From these two data sets, the magnitude, the direction and the position of load can be obtained. Theory and practice do not always coincide; since there are some errors such as ill-poseness, measuring error and modeling error in experimental data, we examine the proper method of error minimization.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.343-356
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• 2022

As a part of round robin analysis to develop a finite element elastic-plastic seismic analysis procedure for nuclear safety class 1 components, a series of parametric analyses was carried out on the simulated pressurizer surge line system model to investigate sensitivity of the analysis results to finite element analysis variables. The analysis on the surge line system model considered dynamic effect due to the seismic load corresponding to PGA 0.6 g and elastic-plastic material behavior based on the Chaboche combined hardening model. From the parametric analysis results, it was found that strains such as accumulated equivalent plastic strain and equivalent plastic strain are more sensitive to the analysis variables than von Mises effect stress. The parametric analysis results also identified that finite element density and ovalization option in the elbow elements have more significant effect on the analysis results than the other variables.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.55-59
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• 2002

Delamination means that cracking occurs on the interface layer between composite laminates. In this paper, to predict the delamination growth in composite laminates subjected to low-velocity impact, the unit load method was introduced, and an eighteen-node 3-D finite element analysis, based on assumed strain mixed formulation, was conducted. Strain energy release rate, necessary to determine the delamination growth, was calculated by using the virtual crack closure technique. The unit load method saves the computation time more than the re-meshing method. The virtual crack closure technique enables the strain energy release rate to be easily calculated, because information of the singular stress field near the crack tip is not required. Hence, the delamination growth in composite laminates that are subjected to low-velocity impact can be efficiently predicted using the above-mentioned methods.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.7-15
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• 1998

An upper bound elemental technique(UBET) program has been developed to analyze forging load, die-cavity filling and effective strain distribution for flash and flashless forgings. The program consists of forward and backward tracing processes. In the forward program, flash, die filling and forging load are predicted. In backward tracing process, the optimum dimensions of initial billet in conventional forging are determined from the final-shape data based on flash design. And the analysis is described for merit of flashless precision forging. Experiments are carried out with pure plasticine billets at room temperature. The theoretical predictions of forging load and flow pattern are in good agreement with the experimental results.

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.65-75
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• 1998

The fracture resistance curve is one of most important and design techniques employed in nuclear pressure vessel structures. This study is to evaluate the J-R curve characteristics for the SA508C-3 by the unloading compliance method and load rato analysis. The effect of strain aging for the exponential correlation of the J-R curve in this metal are investigated at room temperature, 20$0^{\circ}C$ and 30$0^{\circ}C$. The load ratio analysis method can evaluate the J-R curve by using the simple tension load-displacement curve only without the repeat of the unloading and loading. Therefore, the analysis by the proposed load ratio method has a merit, in comparison with the unloading compliance method, which can measure the crack length without the precision measurement equipment.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.119-127
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• 1998

Assuming that the static loaded square tube and the dynamic loaded one have no difference in their characteristics of the crush distance, the theoretical mean dynamic crush load was calculated with respect to the impact speed considering the strain rate sensitivity of the material. The ratio of dynamic to static mean crush load was predicted with previous results. The theoretical analysis was compared with the experimental results of aluminum square tubes axially loaded dynamically.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2165-2172
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• 1995

Optimization of mesh discretization has been proposed to improve the accuracy of limit analysis solution of collapse load by using the Rigid Body Spring Model(R. B. S. M) under the plane strain condition. Moreover, the fracture behaviour of materials was investigated by employing the fracture mechanism of a spring connecting the triangular rigid body element. It has been clarified that the collapse load and the geometry of slip boundary for optimized mesh discretization were close to those of the slip line solution. Further, the wedge-shaped fracture of a cylinder under a lateral load and the central fracture of a strip in the drawing process were well simulated.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2054-2057
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• 2005

In this paper, the application of finite element method to design the shape of load cell as an illustrative case study is described. The relationship between the various shapes of load cell and their stress characteristic were analyzed by COSMOS simulation program. The results obtained from the proposed analysis can be applied to determine the appropriate position of strain gauges for good quality load cell. The experimental results show the good efficiency of the proposed technique.

• Structural Monitoring and Maintenance
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• v.3 no.2
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• pp.145-155
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• 2016

The Pulse-Pre Pump Brillouin Optical Time Domain Analysis (PPP-BOTDA) technique is introduced to implement the multi-direction strain measurement. The monitoring principle is stated. The layout scheme of optical fibers is proposed. The temperature compensation formula and its realizing method are given. The experiments, under tensile load, combined bending and tensile load, are implemented to validate the feasibility of the proposed method. It is shown that the PPP-BOTDA technique can be used to discriminate the multi-direction strains with high spatial resolution and precision.

• Journal of Biosystems Engineering
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• v.42 no.4
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• pp.251-257
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• 2017

Purpose: A chisel mounted on working implement, such as agricultural machinery used in irregular farming conditions, is subjected to highly variable fatigue loading during work. To ensure the safety of the chisel on a working implement for the duration of its service life, fatigue testing must be performed with the proper fatigue test load conditions. In this study, working loads for a chisel were developed by reconstructing loads from strain gage data collected during field tests and used to conduct fatigue tests on the chisel component. Methods: FE analysis with nCode software was utilized to select the proper quantity and locations of strain gages for load measurements. A fatigue test was performed to experimentally verify the fatigue strength of the chisel and to evaluate the validity of the load history developed with the load reconstruction technique. Results: A strain history for the chisel was obtained from data collected during field tests. The data was filtered for the 14-16 km/h speed range, connected, and merged. The chisel load history was developed using the load reconstruction technique. The resulting load history was expressed as a load spectrum using the rain-flow counting method. Conclusions: A fatigue test was conducted on a chisel under a constant load condition with an equivalent load amplitude and number of cycles, as calculated by Miner's Rule for linear damage accumulation. During the fatigue test, there were no cracks at any position. It is concluded that the fatigue test method proposed in this study can be utilized successfully as a durability evaluation method for the chisel.