• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.612-617
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• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• Steel and Composite Structures
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• v.30 no.6
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• pp.551-565
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• 2019

A total of 36 carbon steel and stainless steel bolted connections subjected to shear loading at different strain rates was experimentally investigated. The connection specimens were fabricated from carbon steel grades 1.20 mm G500 and 1.90 mm G450, as well as cold-formed stainless steel types EN 1.4301 and EN 1.4162 with nominal thickness 1.50 mm. The connection tests were conducted by displacement control test method. The strain rates of 10 mm/min and 20 mm/min were used. Structural behaviour of the connection specimens tested at different strain rates was investigated in terms of ultimate load, elongation corresponding to ultimate load and failure mode. Generally, it is shown that the higher strain rate on the bolted connection specimens, the higher ultimate load was obtained. The ultimate loads were averagely 2-6% higher, while the corresponding elongations were averagely 8-9% higher for the test results obtained from the strain rate of 20 mm/min compared with those obtained from the lower strain rates (1.0 mm/min for carbon steel and 1.5 mm/min for stainless steel). The connection specimens were generally failed in plate bearing of the carbon steel and stainless steel. It is shown that increasing the strain rate up to 20 mm/min generally has no effect on the bearing failure mode of the carbon steel and stainless steel bolted connections. The test strengths and failure modes were compared with the results predicted by the bolted connection design rules in international design specifications, including the Australian/New Zealand Standard (AS/NZS4600 2018), Eurocode 3 - Part 1.3 (EC3-1.3 2006) and North American Specification (AISI S100 2016) for cold-formed carbon steel structures as well as the American Specification (ASCE 2002), AS/NZS4673 (2001) and Eurocode 3 - Part 1.4 (EC3-1.4 2015) for stainless steel structures. It is shown that the AS/NZS4600 (2018), EC3-1.3 (2006) and AISI S100 (2016) generally provide conservative predictions for the carbon steel bolted connections. Both the ASCE (2002) and the EC3-1.4 (2015) provide conservative predictions for the stainless steel bolted connections. The EC3-1.3 (2006) generally provided more accurate predictions of failure mode for carbon steel bolted connections than the AS/NZS4600 (2018) and the AISI S100 (2016). The failure modes of stainless steel bolted connections predicted by the EC3-1.4 (2015) are more consistent with the test results compared with those predicted by the ASCE (2002).

• Journal of the Society of Naval Architects of Korea
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• v.48 no.4
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• pp.330-335
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• 2011

This paper presents estimation of average compressive strengths of three types of stiffened panels under lateral pressure and axial compression based on simplified formulas from CSRs and nonlinear FEAs. FEA scenarios are prepared based on the slenderness ratios of the stiffened panels used for in-service vessels. The seven step lateral pressures by 1bar increment are imposed on FE models assuming maximum 30m water height. The number of FEAs for FB-, AB-, and TB-stiffened panels is totally 189 times. FEA results show that existence of pressure can evolves significant reduction of ultimate strengths, meanwhile CSR formulas do not take into account the lateral pressure effect. Lateral pressure acting on the stiffened panel with higher column slenderness ratio more reduces the ultimate strengths than those with smaller column slenderness ratio. A new concept of relative average compressive strain energy instead of the ultimate strength is introduced in order to rationally compare the average compressive strength through complete compressive straining regime. The differences of the ultimate strengths between CSR formulas and FEA results are relatively small for FB- and AB-stiffened panels, but larger discrepancies of relative average compressive strain energies are shown.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.59-67
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• 2002

The comparison of $J_{Rice}$-resistance considering a few strength ratio in Rice J-integral formula and $J_{\delta}$-resistance curves converted from experimental CTOD using appropriate strength chosen according to strain hardening level, n=10.6 (A533B steel) and n=8.1 (BS4360 steel) is carried out. The optimal dimensionless strength ratio like the factor of revision, (see full text)reflecting strain hardening level in Rice\`s experimental formula is found out and the reliability of appropriate reference strength chosen according to strain hardening level in different materials is investigated through doing that CTOD is transformed from $J_{\delta}$-integral using relationship between J-integral and CTOD. The results are as follows; 1) The optimal factor of revision is when m equals to 3 in (see full text) for Rice's and the above optimal factor of revision multiplies by coefficient, η in Rice's experimental formula instead of n=2, 2) and the pertinent reference strength for high strain hardening material like BS4360 steel is ultimate strength, $\sigma_{u}$ and for material like A533B steel is ultimate-flow strength, $\sigma_{u-f}$. The incompatible of the behavior of both experimental J-resistance curves using Rice's formula and CTOD-resistance curves for A533B and BS4360 steel by Gordon, et al., could be corrected using the optimal factor of revision in Rice\`s and the pertinent reference strength in J=$m_{j}$${\times}$$\sigma_{i}$${\times}$CTOD.

• Structural Engineering and Mechanics
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• v.11 no.5
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• pp.519-534
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• 2001

The effect of the initial imperfections on the nonlinear behaviors and ultimate strength of the thin-walled members subjected to the axial loads, obtained by the finite element stability analysis, are examined. As the initial imperfections, the bucking mode shapes of the members are adopted. The buckling mode shapes of the thin-walled members are obtained by the transfer matrix method. In the finite element stability analysis, isoparametric degenerated shell element is used, and the geometrical and material nonlinearity are considered based on the Green Lagrange strain definition and the Prandtl-Reuss stress-strain relation following the von Mises yield criterion. The U-, box- and I-section members subjected to the axial loads are adopted for numerical examples, and the effects of the initial imperfections on the nonlinear behaviors and ultimate strength of the members are examined.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.167-172
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• 2002

Nonlinear analysis of the reinforced concrete beam subjected to torsion is presented. Seventeen equations involving seventeen variables are derived from the equilibrium equation, compatibility equation, and the material constitutive laws to solve the torsion problem. Newton method was used to solve the nonlinear simultaneous equations and efficient algorithms are proposed. Present model covers the behavior of reinforced concrete beam under pure torsion from service load range to ultimate stage. Tensile resistance of concrete after cracking is appropriately considered. The softened concrete truss model and the average stress-strain relations of concrete and steel are used. To verify the validity of Present model, the nominal torsional moment strengths according to ACI-99 code and the ultimate torsional moment by present model are compared to experimental torsional strengths of 55 test specimens found in literature. The ultimate torsional moment strengths by the present model show good results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.145-152
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• 2005

This paper presents a deformable strut-and-tie model of determining the shear strengths and ultimate deformations of the shear-dominant reinforced concrete members. The proposed model originates from the strut-and-tie model concept and satisfies equilibrium, compatibility, constitutive laws, and the geometric conditions of shear deformation. This study attempts to apply deformation patterns to strut-and-tie models. The yielding of flexural reinforcements determines yielding states and the ultimate states of reinforced concrete coupling beam are defined as the ultimate compressive strain of struts and the degradation of compressive strength due to principal tensile strain of struts. The validity and accuracy of the proposed model is then tested against available experimental data. The parameters reviewed include the ratios of truss action and arch action, the reinforcement ratios, and the shear span-depth ratio. It is expected that this model can be applied to displacement-based design methods.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.157-165
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• 2002

Nonlinear analysis of the reinforced concrete beam subjected to torsion is presented. Seventeen equations involving seventeen variables are derived from the equilibrium equation, compatibility equation, and the material constitutive laws to solve the torsion problem. Newton method was used to solve the nonlinear simultaneous equations and efficient algorithms are proposed. Present model covers the behavior of reinforced concrete beam under pure torsion from service load range to ultimate stage. Tensile resistance of concrete after cracking is appropriately considered. The softened concrete truss model and the average stress-strain relations of concrete and steel are used. To verify the validity of present model, the nominal torsional moment strengths according to ACI-99 code and the ultimate torsional moment by present model are compared to experimental torsional strengths of 55 test specimens found in literature. The ultimate torsional moment strengths by the present model show good results.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.139-142
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• 2005

This paper presents a deformable strut-and-tie model of determining the shear strengths and ultimate deformations of the shear-dominant reinforced concrete members. The proposed model originates from the strut-and-tie model concept and satisfies equilibrium, compatibility, constitutive laws, and the geometric conditions of shear deformation. This study attempts to apply deformation patterns to strut-and-tie models. The yielding of flexural reinforcements determines yielding states and the ultimate states of reinforced concrete coupling beam are defined as the ultimate compressive strain of struts and the degradation of compressive strength due to principal tensile strain of struts. The validity and accuracy of the proposed model is then tested against available experimental data. The parameters reviewed include the ratios of truss action and arch action, the reinforcement ratios, and the shear span-depth ratio. It is expected that this model can be applied to displacement-based design methods.

• Journal of Korean Port Research
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• v.14 no.3
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• pp.331-340
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• 2000

For the rational and economic design of the structural elements of ships which is built using welding, the ultimate strength analyses of the plates having initial imperfections, such as welding residual stresses and strains, are needful. The welding deformation usually relied on approximative equations or based on expert's experience. But in this paper, for the thermal elasto-plastic analysis of plates, the finite element analysis was performed, based on initial strain method. In formulating the incremental analysis, unbalanced force terns were included. In the plastic domain during the incremental process, the 2nd order terns stress increment and yield stress increment were considered, so that time increment could be controlled for a more stable solution. The ultimate strength analysis program of the plates having initial imperfections was made. The ultimate strength analysis was carried out based on the results of the welding deformations of this paper. In the ultimate strength analysis the Rayleigh-Ritz method based on the minimum potential theory was used.