Abstract: The fatigue life of hexagon head and socket head bolts, attached to vehicle a wheel, is
assessed and the estimation of the residual life of existing bolts in vehicle wheel is investigated. Fieldmeasured
load histories were applied in this test. Tensile tests and fatigue tests were performed to
evaluate the effect of tightening torque and to obtain the basic experimental data. Miner’s rule was
used to predict the fatigue life of bolts. The results indicate the prediction of fatigue life of the bolts
was in good agreement with the real life of vehicle wheel bolts in this test.
Abstract: For strain-softening materials with different elastic modulus of tensile compression, two
controlling parameters were introduced to take into account the different modulus and strainsoftening
properties. By means of twin shear unified strength theory, unified solutions calculating
stress and displacement fields of expansion of cylindrical cavity were derived. The effects caused
by different elastic modulus in tensile and compression, different models and strain-softening rates
on stress and displacement fields, development of plastic zone were analyzed. The results show the
ultimate expansion pressure, stress and displacement fields and development of plastic zone vary
with the changes of different elastic modular, different models and strain-softening properties.
Abstract: Partially High Percentage Fiber Reinforced Concrete (PHPFRC) is a kind of cement
composite in which fibers are concentrated with high volume fraction in the tension region of the
component under bending. Therefore, PHPFRC possesses much higher load bearing capacity,
rigidity, fatigue and fracture properties than conventional steel fiber reinforced concrete (SFRC)
while its cost is similar to that of SFRC. In this paper, the fatigue test of PHPFRC is carried out to gain
its flexural fatigue damage evolution rule. It is found from the test that, PHPFRC have long
post-crack fatigue life and its fatigue damage is tough damage. Based on the continuum damage
mechanics and fatigue behavior of the specimens, a fatigue damage variable D for PHPFRC is
defined and the elementary form of damage evolution function is determined. For the specimens in
which average fiber volume fraction are 1.2% and local fiber volume fraction are 10%, the function
parameters and the damage threshold value are given according to the test results.
Abstract: Based on the classic laminate theory, a progressive damage model has been incorporated
into the composite structure analysis by using a commercial code, ABAQUS, via one of its
user-defined subroutine, UGENS. The developed user subroutine can be applied to simulate fiber
and matrix damage processes in the general composites structures. The responses of flat laminate
subjected to static contact crush have been studied to verify the efficiency of the presented damage
method. The predicted load-displacement relationships, damage distribution were obtained and
compared with the corresponding experiments, and the results were found to be in good agreement.
Abstract: A crack in the tooth root, which often leads to failure in gear unit operation, is the most
undesirable damage caused to gear units. This article deals with fault analyses of gear units with real
damages. Numerical simulations of real operating conditions have been used in relation to the
formation of those damages. A laboratory test plant has been used and a possible damage can be
identified by monitoring vibrations. The influences of defects of a single-stage gear unit upon the
vibrations they produce are presented. Signal analysis has been performed also in concern to a
non-stationary signal, using the Time Frequency Analysis tools. Typical spectrograms, which are the
result of reactions to damages, are a very reliable indication of the presence of damages.
Abstract: This paper presented the results for experimental investigations and numerical analysis
performed with the aim of studying on fatigue life of hobbed and cold forged bevel gears used in
automobiles. To evaluate the bending fatigue strength improvement by cold forging process, fatigue
test and analysis were performed. For the monotonic fatigue loading, bending fatigue test and
analysis were carried out. To simulate the real driving condition, random fatigue loading was
defined here, and the random fatigue analysis was also performed. It was concluded that fatigue life
and crack initiation sites of automotive bevel gear were well agreed with the test results. Fatigue
lives for hobbed and cold forged bevel gear from experimental and analytical investigation were
also presented and compared.
Abstract: Electro-Active Paper (EAPap) materials based on cellulose are attractive for many
applications because of their low voltage operation, lightweight, dryness, low power consumption,
bio-degradability. The construction of EAPap actuator has been achieved using the cellulose paper
film coated with thin gold electrode layers. This actuator showed a reversible and reproducible
bending movement. In order to improve both force and displacement of this, efforts are made to
construct hybrid EAPap actuators using cellulose paper coated with carbon nanotubes (CNT). To
coat the CNT, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes
(MWCNT) are dispersed in polyaniline (PANI) matrix, and the solution is coated on the EAPap by
using a spin coater. It is expected that the use of CNT can improve the force output by enhancing
the stiffness of the hybrid EAPap actuator. Furthermore, the presence of the PANI may improve the
actuation performance of the EAPap material. The performance of hybrid EAPap actuators is tested
in an environmental chamber in terms of free displacement, blocked force and electrical power
consumption. The performance of hybrid actuators is investigated for bio-mimetic applications.
Abstract: The fatigue behaviour of the welded beam-to-column connections of steel moment
resisting frame in seismic area must be evaluated. The cohesive zone model is an efficient solution
to study such connections by finite elements. It respects the energetic conservation and avoids
numerical issues. A three-dimensional cohesive zone model element has been implemented in the
home made finite element code Lagamine . It is coupled with the fatigue continuum damage
model of Lemaître and Chaboche . The cohesive parameters are identified by the inverse method
applied on a three points bending test modelling.
Abstract: The influence of fatigue ratio on the low cycle fatigue damage of nodular cast iron was
investigated by measuring the elastic modulus. The results indicated that the elastic modulus of
nodular cast iron is a sensitive parameter to the fatigue damage at low cycle. The fatigue damage
variable of nodular cast iron increases with cycle ratio. At the beginning and end period of cycling,
the damage of nodular iron increases sharply, and in the range of 0.2- 0.8 cycle ratio, the fatigue
damage grows gradually.
Abstract: In this paper, the strength of the singular stress field near the ends of the CNTs in
composites was analyzed to clarify the effects of the CNT length on stress filed in the CNT reinforced
composites when studying the fracture toughness. The singular stress field was separated into two
types of singularities, symmetric and skew-symmetric, near the ends of CNTs according to the
deformation and loading types. The stress intensity factors of the singular stress field were calculated
for these two types of singularities. The effects of the CNT length in CNT reinforced composites on
these stress intensity factors were investigated.