• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.997-1006
• /
• 2010

For manufacturing modern cars, so-called multi-materials, such as aluminum alloy with high-strength steels, are used. For obtaining such materials, a new joining method is required to achieve the multi-material design. Mechanical clinching is one of joining methods used to join the dissimilar materials. The objective of this study is to investigate the characteristics of mechanical clinching of Al5052 alloy to high-strength steels (SPFC440, 590, 780). Using FE-analysis and clinching experiment, the joinability of Al5052 alloy to high-strength steel is evaluated by geometrical shape of mechanical clinched joint, such as neck-thickness and undercut. Further, the joint strength is evaluated by performing a single-lap shear test. The upper high-strength steel SPFC780 was not clinched because of the necking of the upper sheet. The joint strength increased with increasing strength of the upper sheet. For the lower high-strength steel sheet, the joinability and joint strength decreased with increasing strength of the lower sheet.

• Korean Journal of Materials Research
• /
• v.9 no.7
• /
• pp.747-752
• /
• 1999

The interfacial reaction and joint properties of Sn-3.5Ag/Cu and Sn-3.5Ag-1Zn/Cu joint were studied. Modified double lap shear solder joints of Sn-3.5Ag and Sn-3.5Ag- lZn solder were aged for 60days at $100^{\circ}C$ and $150^{\circ}C$ and then loaded to failure in shear. The Sn-3.5Ag/Cu had a fast growth rate of the reaction layer in comparison with the Sn-3.5Ag-lZn at the aging temperature of $150^{\circ}C$ Through the SEM/EDS analysis of solder joint, it was proved that intermatallic layer was $Cu_{6}Sn_5$ phase and aged specimens showed that intermatallic layer grew in proportion to $t_{1/2}$, and the precipitate of $Ag_3Sn$ occur to both inner layer and interface of layer and solder. In case of Zn-containing composite solder, $Cu_{6}Sn_{5}$ phase formed at the side of substrate and $Cu_{5}Zn_{8}$ phase formed at the other side in double layer. The shear strength of the Sn-3.5Ag/Cu joint improved by addition of IZn. The strength of the joint increases with strain rate and decreases with aging temperature

• Steel and Composite Structures
• /
• v.21 no.2
• /
• pp.323-342
• /
• 2016

To study the effect of collar-plate reinforcement on the static strength of tubular T-joints under axial loading, fundamental research work is carried out from both experimental test and finite element (FE) simulation. Through experimental tests on 7 collar-plate reinforced and 7 corresponding un-reinforced tubular T-joints under axial loading, the reinforcing efficiency is investigated. Thereafter, the static strengths of the above 14 models are analyzed by using FE method, and it is found that the numerical results agree reasonably well with the experimental data to prove the accuracy of the presented FE model. Additionally, a parametric study is conducted to analyze the effect of some geometrical parameters, i.e., the brace-to-chord diameter ratio ${\beta}$, the chord diameter-to-chord wall thickness ratio $2{\gamma}$, collar-plate thickness to chord wall thickness ratio ${\tau}_c$, and collar-plate length to brace diameter ratio $l_c/d_1$, on the static strength of a tubular T-joint. The parametric study shows that the static strength can be greatly improved by increasing the collar-plate thickness to chord wall thickness ratio ${\tau}_c$ and the collar-plate length to brace diameter ratio $l_c/d_1$. Based on the numerical results, parametric equations are obtained from curving fitting technique to estimate the static strength of a tubular T-joint with collar-plate reinforcement under axial loading, and the accuracy of these equations is also evaluated from error analysis.

• Earthquakes and Structures
• /
• v.10 no.2
• /
• pp.313-328
• /
• 2016

Beam-column joints are recognized as one of the most critical and vulnerable zones of a Reinforced Concrete (RC) moment resisting structure subjected to seismic loads. The performance of the deficient beam-column joints can be improved by retrofitting these joints by jacketing them with varied materials like concrete, steel, FRP and ferrocement. In the present study strength behavior of RCC exterior beam-column joints, initially loaded to a prefixed percentage of the ultimate load, and retrofitted using ferrocement jacketing using two different wrapping schemes has been studied and presented. In retrofitting scheme, RS-I, wire mesh is provided in L shape at top and at bottom of the beam-column joint, whereas, in scheme RS-II along with wire mesh in L shape at top and bottom wire mesh is also provided diagonally to the joint. The results of these retrofitted beam-column joints have been compared with those of the controlled joint specimens. The results show an improvement in the ultimate load carrying capacity and yield load of the retrofitted specimens. However, no improvement in the ductility and energy absorption has been observed.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.453-458
• /
• 2008

Under driving condition, A vehicle experiences various kinds of loads, which brings on the buckling and fracture of suspension systems. Lower control arm (LCA), which consists of 2 bush joints and 1 ball joint connection, is the one of the most important parts in the suspension system. The bush joints absorb the impact load and reduce the vibration from the road. When analyzing the LCA behavior, it is important to understand the material properties and boundary conditions of bushing systems correctly, because of the nonlinearity characteristics of the rubber. In this paper, in order to predict the large scale deformation of the LCA more precisely, three factors are newly suggested, that is, coupling of bush stiffness between translation and rotation, bush extraction force and maximum rotation angle of ball joint. LCA stiffness is estimated by CAE and component test. Analysis and test results are almost same and the validity of considering three factors in LCA analysis is verified.

• Advances in Traditional Medicine
• /
• v.10 no.2
• /
• pp.66-78
• /
• 2010

Acute (24 h) and chronic (90 days) oral toxicity studies on the ethanol extract of Trigonella foenumgraecum Leguminosae (L.) seeds were carried out. Acute dosages were 0.5, 1.0 and 3 g/kg while chronic dosage was 100 mg/kg per day of the extract. All morphological, biochemical, haematological and spermatogenic changes, in addition to mortality, body weight changes and any change in vital organs were recorded. Histopathological investigations were done on vital organs. Growth arrest in the treated animals was observed. The treated mice gained no significant weight during chronic treatment while there was a significant gain in body weight of the control group mice. Biochemical studies revealed a significant decrease in blood sugar levels of fenugreek treatment groups while haematological parameters remained comparable to the control. In the treatment, male group there was a significant decrease in weight of testes as compared to the control. There was a marginal weight gain in kidney weight of mice after chronic treatment as compared to the control. Fenugreek chronic treatment caused a highly significant spermatotoxic effects in male mice.

• Tunnel and Underground Space
• /
• v.19 no.1
• /
• pp.52-63
• /
• 2009

This is a study on large-scale rock joint roughness measurements using LIDAR (light detection and ranging) and the Split-FX point cloud processing software. The large-scale rock Joint Roughness Coefficient (JRC) is calculated using the maximum amplitude of joint asperities over the profile length on large-scale Joint surfaces of rock. As the profile length increases, JRC decreases due to scale-effects of rock specimens and is non-stationary. Also JRC shows anisotropy depending on the profile direction. The profile direction is measured relative to either dip or strike of the large-scale joint.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.43
• /
• pp.197-204
• /
• 1997

Torques on each joint, the compression on L5/S1 disc, the force on hand of a rider are estimated using a static biomechnic model. Forces that the rider applies to the pedals, saddle and handle during starting and speeding are estimated using static mechanics. Physical stress is considered accroding to handle height and horizontal distance between handle and pedal. When handle height is higher in normal speeding, the force on handle and sum of torques on each joint decreases.

• Journal of Korean Physical Therapy Science
• /
• v.8 no.2
• /
• pp.997-1003
• /
• 2001

The purpose of this study is to know the average of pint range of motion and difference according to the aging for the elderly, This study consisted of elder male(n=75) and elder female(n=l09), The result of assessment and analysis in shoulder pint range of motion are as follows: 1) The average shoulder flexion pint range of motion in 60-69(from sixty to sixty-nine)years old are 163.04(Left-Male), 162.91(Right-Male), 158.74 (Left-Female), 158.74 (Right-Female). 70-79years old are 149.40(L-M), 152.38(R-M), 153,37(L-F), 153.37(R-F). 80-89 years old are 149.57(L-M), 147.93(R-M), 151.17(L-F), 150.33(R-F). There was no significant difference among group, 2) The average shoulder extension pint range of motion in 60-69years old are 48.15(L-M), 47.20(R-M), 45.16(L-F), 44.23(R-F), 70-79years old are 37.l1(L-M), 38.70(R-M), 35.17(L-F), 36.71(R-F), 80-89 years old are 34.46(L-M). 36.71(R-M), 33.90(L-F), 33.09(R-F). There was significant difference among group(p<.05). 3) The average shoulder abduction pint range of motion in 60-69years old are 164.22(L-M), 165.96(R-M), 159.34(L-F), 159.97(R-F), 70-79years old are 152.27(L-M), 155.05(R-M), 152.32(L-F), 53.66(R-F), 80-89 years old are 152.17(L-M), 153.76(R-M), 147.53(L-F), 147.37(R-F). There was significant difference in right shoulder abduction among group(p<05). 4) The average shoulder internal rotation pint range of motion in 60-69years old are 63.52(L-M), 65.70(R-M), 64.16(L-F), 64.61(R-F), 70-79years old are 64.50(L-M), 65.81(R-M) 61.10(L-F), 61.83(R-F). 80-89 years old are 61.60(L-M), 61.66(R-M), 57.53(L-F), 57.53(R-F). There was no significant difference among group. 5) The average shoulder external rotation pint range of motion in 60-69years old are 50.87(L-M), 50.22(R-M), 51.03(L-F), 50.42(R-F), 70-79years old are 50.91(L-M), 50.20(R-M) 48.37(L-F), 50.20(R-F). 80-89 years old are 46.83(L-M), 47.93(R-M), 43.43(L-F), 43.72(R-F).There was significant difference in left shoulder external rotation among group(p<.05).

• Journal of applied mathematics & informatics
• /
• v.35 no.3_4
• /
• pp.231-239
• /
• 2017

In this paper, we prove common fixed point theorems for $\mathcal{L}$-fuzzy mappings under implicit relation in b-metric spaces. Further, results obtained for an integral type contractive condition. These theorems generalize and improve previous corresponding results.