Abstract: This study contains several estimation methods of the static buckling load for the spacer
grid of nuclear fuel assembly in pressurized water reactor. Three different estimation methods were
proposed for the calculation of the static buckling loads of spacer grid. The linear and non-linear
static buckling analyses were performed to estimate the static buckling load of the spacer grids
using ANSYS program. The analyses results were compared with the static buckling test results.
Based on the analysis and test results, the applicability of the proposed estimation method for the
static buckling load of the spacer grid was investigated.
Abstract: The precision diagnosis of subway electric multiple units (EMUs) was conducted with
various types of engineering analysis techniques for the current performance and wear evaluation.
The evaluation was conducted on detailed parts of EMUs, such as car bodies, bogies, braking
systems, and electrical systems of EMUs. Several characterization means including nondestructive
evaluation techniques, corrosion testing, and three-dimensional measurements, were employed for
the evaluation of car bodies and bogies. For braking system, degradation and performance tests
were conducted, while the functional and degradation tests were performed on electrical system in
order to identify the actual performance of the system. Moreover, stress and structural analyses
using commercial finite element method (FEM) software provided important information on stress
distribution and load transfer mechanisms. In this investigation, various advanced engineering
analysis techniques for the safety analysis of subway EMUs have been introduced and the analysis
results have been used to provide the critical information for the criteria of safety assessment.
Abstract: During fuel irradiation tests of material and fuel rods, all parts of cylindrical shells with
multiple holes act as heat sources due to fission heat and γ-flux. The thermal stress is induced by a
temperature difference among the heat sources. In this study, the thermal stress of the cylindrical
structure is minimized by using an optimization method about the geometric variables. The circular
shapes of the multi-specimens are investigated. For the thermal analysis of the structure, the finite
element method code, ANSYS 8.1 is used. A sub-problem approximation method is used for the
structural design optimization.
Abstract: The difference in the Coefficient of Thermal Expansion (CTE) between the chip and the
substrate generate thermal displacement in the solder joint. It seems to be a main cause of failure in
the solder joint when the chip and the substrate are heated repeatedly. The failure of the solder
joints by thermal fatigue is known to be influenced by varying boundary conditions such as the
difference in CTE, the height of solder, the Distance of the solder joint from the Neutral Point
(DNP) and the temperature variation. In this paper, the effects of varying boundary conditions on
the failure probability of the solder joint are studied by using the probabilistic approach methods
such as the First Order Reliability Method (FORM) and the Second Order Reliability Method
Abstract: The resonance phenomenon is suppressed by adjusting the damping of the comb
accelerometer structure to widen the frequency bandwidth of the capacitive accelerometer. The
capacitive accelerometer with asymmetrical combs, fabricated with DRIE and anodic bonding, is
presented. The damping category of the accelerometer is introduced, in which the squeeze-film
damping coefficient and the damping ratio factor are detailed. The damping ratio factor of the
accelerometer, measured by a vibration method, is 0.17. The damping ratio factor of the optimized
structure is calculated of 0.15 to 0.18 with the change of experiential modulus C from 25 to 30,
Abstract: Pressure steel pipings in a water power plant have been in service for over fifty years. In
order to assess the safety of the piping, whole check and tests for the piping were carried out. The
material for some piping is ST3 from former USSR, the other is A3 made in China. The mechanical
properties were investigated by tests and were compared with the original material properties. The
result shows the yield strength and tensile strength of serviced steels are less than those of original
materials. The surfaces of the piping were checked to investigate the corrosion, surface defects. The
flaws in the welds and near the welds of the pipings were detected by UT and MT, and several weld
flaws were found. Based on the test and NDT investigation results, the strength, fracture and fatigue
life of the pipings are assessed according to Chinese standard GB/T19624-2004 and British standard
BS7910-2000. The assessment results show that the strength of the piping is enough, and the pipings
with these flaws does not fracture. The piping can be safe in service under the normal operating
condition for 104 to 106 cycles.
Abstract: The measurement of crack propagation in solids is of vital importance for the research of
the fatigue characteristic of solid materials. By analysis of the image based measurement technique,
a contact-free crack measurement approach was proposed based on image cross correlation
algorithm. Experiment was performed to verify the validity of this method and it was found that the
method is of high precision. The approach distinguished itself from traditional methods by several
characteristics: it has relatively high measuring accuracy, the crack propagation can be continuously
measured with this method, the amount of information that the approach provide is much more
abundant than that of other methods. The method is proved to be an efficient method for crack
measurement and can be applied in fatigue induced material cracking researches.
Abstract: The corrosion behaviors of thixoformed AZ91D alloy immersed in 3.5% NaCl aqueous
were studied by using the weight lose method and observed by scanning electron microscopy and
analyzed by electron probe micro-analysis.The results showed that corrosion rate of thixoformed
AZ91D alloy was higher in initial stages and decreased as the immersion time increased. Compared
with the thixoformed alloy, the change of corrosion rate of permanent mould cast (PMC) alloy was
smoothly. The observation on the corrosion surfaces showed that the primary αphase spherical
particles were first suffered from corrosion during corrosion testing, and then the eutecticαgrains.
the composition of primaryαphase particles in the thixoformed alloy was quite uniform, and thus the
protective film of the corrosion products on the alloy surface was more intact. The amount of the
eutectic β phase in the inter-particle eutectics was relatively higher and the distribution was more
uniform, so the protective film consisted by eutectic β phase was also more intact. That is to say the
protective role from the surface film on the thixoformed alloy was better than that on the PMC alloy
which was the cause of lower corrosion rate of the thixoformed AZ91D alloy.
Abstract: The paper deals mainly with the corrosion of 16Mn steel under the condition of three
different high temperatures and in NACE solution saturated with H2S at 1MPa partial pressure of
CO2, by means of autoclave, SEM, XRD, weight loss method and electron-probe micro-analysis.
The result showed: under the experimental conditions, the serious CO2/H2S corrosion happened to
16Mn steel ,so that the main corrosion films, ferrous sulfide, could be clearly found on both sides of
the samples; at 60°C, characteristics of pitting corrosion manifested centered chiefly around CO2
corrosion ; at 90°Cand 120°C, around H2S ones . It was the cooperating effects of both the
hydrogen damage and pitting corrosion caused by CO2/H2S corrosion that formed the special
corrosion features on the surface of steel to a certain degree. It was indicated that the corrosion of
CO2/H2S was the result of interaction of multi-factors.
Abstract: Since the construction method of tailings dams determines the uneven distribution of
tailings, a reliability theory is introduced to analyze the stability of tailings dams. Based on the limit
equilibrium method and reliability theory, the sensitivity and reliability of a typical tailings dam are
analyzed. Reliability analyses with different types of the variable probability distribution types
show that the effect of the probability distribution type on reliability analysis can almost be ignored.
Besides, the sensitivity analyses of different variables show that the strength indexes and density of
tailings will affect the analysis results of stability reliability. Therefore the strength indexes c, φ
and density ρ must be considered as basic variables to analyze the stability reliability of tailings