Abstract: Effect of the applying twin laser beam on the welding of AZ31 / A5052 dissimilar metals
lap joint was studied. The direct welding and the welding with Al12Si filler wire were carried out.
Flow behavior of the molten metal was analyzed by FEM simulation. For both welding methods,
failure load of the joints increased by applying twin laser beam with reasonable beam distance. Twin
laser beam technique could control temperature distribution and flow behavior of the molten metal.
Abstract: This research was concerned with study of failure strength of natural fiber reinforced
composites. Tensile-shear tests were carried out with single-lap-adhesive-joined specimens
consisting of polyester lap and composite lap. Composites were manufactured using the polyester as
matrix and bamboo natural fiber layer as reinforcement. Two types of specimens with different
reinforcement positions were tested to evaluate the failure strength of adhesive-single-lap-joined
natural fiber reinforced composites. The test results were presented by tensile-shear strength graph
comparing with finite element analysis. The failure mechanism was discussed in order to explain the
lower tensile-shear strength of composite, and effect of position of bamboo natural fiber layer on the
failure strength properties were explained.
Abstract: This research was concerned with study of fracture strength of adhesive-lap-joined
composites. The tensile and peel tests were carried out with specimens manufactured hybrid stacked
composites, because the orientation of fiber and the interfacial fracture between the matrix and the
reinforcement had influence on failure strength of composites. Bamboo natural fiber layer was located
between polyester layers. The objective of this study was to evaluate the effect of fiber orientation on
failure strength properties of composites. The test results were presented by load-displacement graph
and finite element analysis. As a result, the load-directional orientation and the thinner thickness of
bamboo natural fiber layer have a good effect on peel and tensile-shear strength and failure shape of
adhesive-joined hybrid stacked composite.
Abstract: The present study is a systematic investigation of the effects of microstructural changes,
which have originated from the variations of filler metals and welding processes, on the J-R
properties of simulated welds. Two AISI Type 347 weld metals, with different carbon contents,
deposited by a GTAW process and two AISI Type 347 weld metals, with different carbon contents,
deposited by a SMAW process were used in this study. The J-R tests were conducted at 316oC (600oF).
The welds deposited by the GTAW process showed higher fracture resistances when compared to the
welds deposited by the SMAW process. The J-R fracture resistance of the Type 347-GTAW
processed weld with high carbon content was remarkably low when compared to the weld with low
carbon. The J-R fracture resistances were decreased by coarse Nb(C, N) precipitates in the Type 347
weld deposited by the GTAW process. In the case of the SMAW welds, mainly coarse Ti-rich
particles which had originated from the shielding of the welding rods deteriorated the fracture
Abstract: This research is concerned with a study of failure strength of natural fiber composite.
Tensile-shear tests were carried out with the single-lap resistance welded joined specimens consisting
of composite materials. Composite materials were manufactured using the polyester as a matrix and
bamboo natural fiber layer as a reinforcement. Two types of specimen with different reinforcement
positions were tested to evaluate the failure strength of natural fiber reinforced composite resistance
welded joined specimens. The test results were presented by tensile-shear strength. The failure
mechanism was discussed in order to explain the lower tensile-shear strength of composite and
position of bamboo natural fiber layer on the failure strength properties were explained
Abstract: Structure adhesive bonding method is widely used in the industry because it is possible to
joint complex shape and dissimilar materials. Especially in the car industry, requests of lightweight
car have adhesive bonding method be applied in the many parts. Also it is possible for stress to
distribute uniformly through the adhesive layer, and stress concentration is released. Since strength,
stiffness durability is much better, this method is determined as the technique replaced weld defect.
But, it has much shorter history then other joint method such as spot weld and mechanical joint
method. Evaluation of strength and durability is not established. As the fundamental research of
design of adhesive bonding joints, considers over-lap length, adhesive thickness, surface treatment
and environment which affect strength and durability of single-lap joints. In this research, a real part
of bus folding door was used and tested to compare durability of spot welding and adhesive bonding.
Abstract: The present paper describes the new methodology used for the development of the crackfree
welding processes. The presented approach is based on the accurate experimental observations
on binary Al-Si alloys, which clearly demonstrate that the crack initiation is a result of the
accumulation of macroscopic tensile strain in a microscopic intergranular liquid film of segregates
at the final stage of the weld metal solidification. The numerical model takes into account the
effects of strain accumulation as well as the influence of thermo-dynamical and thermo-mechanical
properties of the welded material. The new approach provides a clear phenomenological
interrelation between the cracking susceptibility, parameters of the welding process and properties
of the base and filler material. It is successfully applied for development of technological means for
elimination of the solidification cracking during welding of aluminium alloys AA6056, such as a
Abstract: The purpose of this paper is to develop an estimation formula of stress concentration
factors of butt-welded components under tensile loading. To investigate the influence of weld bead
profiles on stress concentration factors of double V groove butt-welded joints, butt-welded
specimens were made by CO2 gas metal arc welding. And the three main parameters, the toe radius,
flank angle and bead height were measured by a profile measuring equipment. By using the
measured data, the influence of three parameters on the stress concentration factors was investigated
by a finite element analysis. It is shown that the three parameters have similar effects on the stress
concentration factors. According to the simulation results, a formula to estimate the stress
concentration factors of butt-weld welded structures was proposed and the estimated concentration
factors from the formula were compared with the results obtained by the finite element analysis.
The two results are in a good agreement.
Abstract: CVD diamond thick film was brazed to cemmented carbide using a Ag-Cu-Ti active filler
metal. The brazing process was performed in a vacuum furnace under different processing condition.
The interfacial microstructure and characterization between diamond and Ag-Cu-Ti filler metal
were studied by SEM, EPMA and EDX. The morphology and distribution of new compound are
shown for the first time (Figs). Results illustrate that a small amount of new compound TiC, TiCu
compound exist in the interface. TiC layer exists in the interface and it's thickness is variational
with the varying of processing condition such as peak heating temperature, keeping time and so on.
New compound TiC accretes with the surface atoms of diamond in a special section, and particular
orientation relationships are occasionally observed by examining the fracture section. TiCu layer
near TiC exists in the interface. It is worth notice that too much TiC and TiCu in interface could
weaken join strength because TiC and TiCu are brittle.
Abstract: Method of Lines (MOLs) is introduced to solve 2-Dimension steady temperature field of
functionally graded materials (FGMs). The main idea of the method is to semi–discretized the
governing equation of thermal transfer problem into a system of ordinary differential equations
(ODEs) defined on discrete lines by means of the finite difference method. The temperature field of
FGM can be obtained by solving the ODEs with functions of thermal properties. As numerical
examples, six kinds of material thermal conductivity functions, i.e. three kinds of polynomial
functions, an exponent function, a logarithmic function, and a sine function are selected to simulate
spatial thermal conductivity profile in FGMs respectively. The steady-state temperature fields of
2-D thermal transfer problem are analyzed by the MOLs. Numerical results show that different
material thermal conductivity function has obvious different effect on the temperature field.