• Laser Solutions
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• v.1 no.1
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• pp.11-17
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• 1998

The electron beam welding system has the advantages of the high power density, narrow welding section, and small thermal distortion of a workpiece. Recently, the electron beam welding system is widely used to the airplane engineering, nuclear power plant, and automobile industry. In the present paper, the structural analyses on the vacuum chamber of the electron beam welding system are performed by the F.E.M. analysis. The stiffening characteristics on the geometric shape, stiffener height and stiffener span are investigated. The deflection of the stiffened vacuum chamber under pressure is minimized by longitudinal and transverse stiffeners which are continuous in both direction.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.701-709
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• 2003

The paper presented the seismic performance of T-stiffener moment connections for use in steel moment-resisting frames. The connections were strengthened by welding the vertical and horizontal clement of the T-stiffener to the beam flange and column f1ange. Finite clement analysis and experiments were conducted to determine the behavior of T-stiffener-reinforced connections. The results of the finite element analysis confirmed the effectiveness of the T-stiffener, whose horizontal element lengthened to mitigate local stress concentrations of the beam flange on the horizontal stiffener. Full-scale specimens were also tested cyclically to study hysteresis behavior. The main parameters used were the ratio of the T-stiffener to beam strength and the shape of the horizontal element. As the length of the horizontal element increased, the deformation capacity of the connections enhanced. Likewise, all specimens behaved according to the Ramberg-Osgood curve and showed stable hysteresis behavior.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.113-121
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• 2004

A test program was conducted on full-scale steel moment connections constructed using a T-stiffener. In the T-stiffener connection, the beam-to-column connection was reinforced with the horizontal and vertical element of the T-stiffener to resist moment under severe cyclic loads. A total of five specimens were tested in this study together with a concrete-filled tubular(CFT) column(${\sqsubset}-500{\times}500{\times}12$) and a steel beam($H-506{\times}201{\times}11{\times}19$). For the specimens, the T-stiffener was combined with RBS (also known as "Dog-bone") detail or Horizontal Element Hole(HEH) detail constructed to enhance deformation capacity. The test program showed excellent seismic performance for specimens constructed with an RBS or an HEH. except the specimens had brittle failure of VE. The test results also showed that the connections all developed maximum moments at the face of the column. Such moments were at least 15% and as much as 36% larger than the plastic moment capacity of the beam. based on the actual yield stress of the beam steel.

• Structural Engineering and Mechanics
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• v.56 no.1
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• pp.67-83
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• 2015

The load transfer mechanism and load-bearing capacity of cast steel joints for H-shaped beam to square tube column connection are studied based on the deformation compatibility theory. Then the monotonic tensile experiments are conducted for 12 specimens about the cast steel joints for H-shaped beam to square tube column connection. The findings are that the tensile bearing capacity of the cast steel joints for beam-column connection depends on the ring of cast steel stiffener. The tensile fracture happens at the ring of the cast steel stiffener when the joint fails. The thickness of square tube column has little influence on the bearing capacity of the joint. The square tube column buckles while the joint without concrete filled, but the strength failure happens for the joint with concrete filled column. And the length of welding connection between square tube column and cast steel stiffener has little influence on the load-bearing capacity of the cast steel joint. Finally it is shown that the load-bearing capacity of the joints for H-shaped beam to concrete filled square tube column connection is larger than that of the joints for H-shaped beam to square tube column connection by 10% to 15%.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.835-843
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• 2002

The goal of this paper is to understand the stress-transfer mechanism of concrete-filled tubular column to H-beam connection with external T stiffener through the elasto-plastic finite element method and to offer basic data for the design of T stiffener. For the accuracy, analysis results are compared with experimental results. It makes use of several stress and strain indices to understand the stress-transfer mechanism of connection. An alternative plan that decreases the stress concentration of beam flange to horizontal stiffener connection is proposed through the elasto-plastic finite element method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.870-875
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• 2004

Beam stiffeners have frequently been used for raising natural frequencies of base structures. In stiffener layout optimization problems, most of the previous researches considering the position and/or the length of the stiffener as design variables dealt with structures having just simple convex shapes such as a square or rectangle. The reason is concave shape structures have difficulties ill formulating geometry constraints. In this paper, a new geometry constraint handling technique, which can define both convex and concave feasible lesions and measure a degree of geometry constraint violation, is proposed. Evolution strategies (ESs) is utilized as an optimization tool. In addition, the constraint-handling technique of EVOSLINOC (EVOlution Strategy for scalar optimization with Lineal and Nonlinear Constraints) is utilized to solve constrained optimization problems. From a numerical example, the proposed geometry constraint handling technique is verified and proves that the technique can easily be applied to structures in net only convex but also concave shapes, even with a protrusion or interior holes.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.375-384
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• 2005

The goal of this paper is to understand the stress-transfer mechanism of concrete-filled tubular column to H-beam connections with external T-stiffener through the finite element method and to offer basic data for the design of T-stiffener. To identify the problems of previous test results, the same shapes of the full-scale test specimens were modeled for the finite element analysis. Results of the analysis were compared with the test results. Several stress and strain indices were used to understand the stress-transfer mechanism of connection with various T-stiffeners parameters. The models of analysis with different T-stiffener are grouped into TS, TSD, and TSH series. An alternative plan that decreases the stress concentration of beam flange to horizontal stiffener connection is proposed through the elasto-plastic finite element method. The basic design idea and minimum sizes of T-stiffener were proposed based on the various indices in relation to the connection details.

• Journal of Korean Society of Steel Construction
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• v.13 no.6
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• pp.715-723
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• 2001

This paper represents the behavior of CFT column to H-beam full-scale connection with external T-stiffener. 6 specimens whose T-stiffeners which are compounded of vertical element and horizontal element were made under the parameter of the strength ratio of each elements(vertical element and horizontal element in T-stiffener) to the beam full plastic moment. The analysis-parameters demonstrated in the base of the data that we get in experiment are strength stiffness, and plastic rotational capacity. All of specimen showed stable hysteretic behavior, and the horizontal element is more critical than vertical element in strength and stiffness. The mean beam plastic rotation of all specimen except the TS-2 specimen is 2.97% rad.

• Bulletin of the Society of Naval Architects of Korea
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• v.2 no.1
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• pp.3-8
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• 1965

The objects of this paper are to stimulated discussion of the criteria used for deciding the scantling of watertight bulkhead stiffener of steel fishing boats ranged of length of 20 meters to 80 meters and to suggest a method of calculation based on beam theory. Present knowledge is examined and it appears that failure of a bulkhead stiffener is comparatively rare. Regarding its structure bulkhead does not contribute on longitudinal strength of a ship. The strength of a bulkhead stiffener can be treated locally. Assuming bulkhead stiffeners are free ends and fixed ends theoretical required section modulus are calculated and compared with classification societies' rule. Welding effect of a bulkhead stiffener to bulkhead plate and a bracket to stiffener and deck plate are considered. On various conditions of joints are suggested.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.247-255
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• 2004

An experimental program was undertaken to develop seismic retrofit methods of existing steel moment connections with floor slab for improved seismic performance. Five full-scale composite specimens were tested under cyclic loading. Conventional through-diaphragm connections [please check this; no search results were found for through-diaphragm connections] composed of square-tube column and H-beam were retrofitted by adding either a bottom-flange dogbone (RBS) or an improved welded horizontal stiffener at the beam bottom flange. The effectiveness of the proposed retrofit connections schemes was evaluated. The specimen retrofitted using the RBS concept at the bottom flange showed poor connection ductility. In contrast. specimens with the proposed horizontal stiffener details exhibited improved connection ductility.