Misan Journal of Engineering Sciences

There are a considerable number of fatigue damage estimation theories and fatigue life prediction of
mechanical components. The most popular one is Palmgren-Minor (P-M) theory. This theory has been used in
the standards for selecting the bearing –as a component subject to fatigue loading- and for expecting the
bearings lives. In Wind Turbine Gearboxes (WTGs), the bearings were selected to be without maintenance for
20 to 25 years; however, in real service life, the bearing suffer from premature failure within a life span of
quite less than the design life (1 to 5 years). A new applicable methodology and a procedure of calculation for
damage estimation due to fatigue loading and predicting the life has been suggested and tested. Results of 20
rolling and sliding tests which conducted under severe contact loading are used to test this method. The
suggested method depends on calculating the number of operating cycles under a specific contact loading
level to an equivalent number of loading cycles under the average loading level. This method depends on the
area under the S-N curve without any correction or loading factors and can be used to predict the WTG
bearings failure to manage the maintenance because the current life prediction standards have very high
percentages of error (> 400%). The reliability of this approach can be further verified by utilizing actual
operational data from Supervisory Control and Data Acquisition (SCADA), used for overseeing wind turbine
operations. Additional examinations are necessary to confirm the dependability of this novel method.

This paper presents a comprehensive analysis of the performance of the Genetic Algorithm
Probabilistic Roadmap (GA-PRM) algorithm in both simulated and real-world robotic environments.
The GA-PRM algorithm is a promising approach for robot path planning, and understanding its behavior
in different settings is crucial for its practical applications. In simulations, we explore the advantages of
controlled and reproducible test conditions, allowing for extensive parameter tuning and algorithm
improvement. Real-world testing is employed to validate the algorithm\'s performance in actual robotic
environments, taking into account the inherent complexities and uncertainties present. In our
comparative analysis, we found that the GA-PRM algorithm demonstrates significant improvements in
real-world scenarios compared to simulations. Specifically, the algorithm produced shorter paths in real-
world robot testing, with an average length of 21.428 cm, as opposed to 25.6235 units in simulations.
Moreover, the computational efficiency of the algorithm was notably enhanced in the real-world
environment, where it took only 0.375 seconds on average to plan paths, compared to 0.6881 seconds
in simulations. The algorithm also exhibited higher path smoothness in the real world, with an average
smoothness score of 0.432, compared to 0.3133 in simulations. These results underscore the algorithm\'s
adaptability to real-world conditions and its potential for efficient navigation in practical healthcare and
automation applications. Our research bridges the gap between simulation and reality, facilitating the
development of more reliable and adaptable robotic systems. The insights gained from this comparative
evaluation contribute to a deeper understanding of the GA-PRM algorithm\'s behavior and its potentials.

Earthquakes are wide-ranging vibrations resulting from the movement of tectonic plates,
causing damage to buildings. In this study, a multi-story steel building is designed using the ETABS
v16 software under vertical loads only. Subsequently, seismic performance was enhanced by
employing five different Mega braced frames (MBFs) systems in two cases: in the first case, the five
bracing systems are placed within a frame located 6 meters away from the outer frame, while in the
second case; the bracing systems were placed within a frame located 12 meters away from the outer
frame. The building was then analyzed using nonlinear time history analysis with SAP 2000 V20
software, utilizing seismic data from the El-Centro earthquake available in SAP 2000 V20. The results
were compared based on various parameters such as maximum roof displacement, maximum inter-
story drift ratio, and maximum base shear. The findings demonstrated an improvement in the
building's response, in the first case maximum roof displacement reduction ranging from 36.08% to
48.29% in both directions, and from 36% to 44% for maximum roof displacement in the second case.
Maximum inter story- drift ratio also reduced by percentages ranging from 25% to 46% in the first
case and 25% to 39% in the second case. From the analysis results, it is evident that the best pattern
in the first case is pattern5, while in the second case pattern4 is the best.

This study examined the impact of replacing the cement weight in concrete with
nanomaterials (mix (C) 1% Carbon Nanotube CNT, mix (T) 2.5% Nano Titanium and mix (S) 3% Nano
Silica) on the concrete mechanical properties through experimental investigations and comparison with
normal concrete to show the extent of the effect of adding nanomaterials on the properties of concrete.
The differences and increasing in the compressive strength for the mix (T) by comparison with the mix
(N) and the mix (S) in the age of 7 days the increasing was 17% and 80% for the mix (S) and (T)
respectively, In the age of 28 days the increasing was 44% and 60% with the mix (S) and (T) respectively
and in the age of 56 days the increasing was 32% and 36% with the mix (S) and (T) respectively. The
compressive strength for mix (C) was decreased 39%, 22%, 13% compared with the compressive
strength for mix (N) at 7, 28 and 56days, respectively. The best improvements in compressive strength
and splitting tensile strength for the mix that was added Nano Titanium (T) replacement by (2.5%) from
weight of cement. For the mixes with nano material, a highest unit weight was observed at the age of 28
days. Referring to the results of SEM (Scanning electron microscope), the effect of nano Silica on the
durability and mechanical properties of concrete can be explained by microstructure and from measuring
X-ray diffraction (XRD) of concrete samples with the added Nano materials, these materials added to
the concrete have clearly affected on the crystalline and chemical structure of the cement mortar
components.

ow variations in fiber ratio impact the structural performance of both solid and hollow
reinforced concrete beams when subjected to pure torsion. Polyolefin fiber was utilized in this study. To
achieve this objective, a total of sixteen specimens of fiber-reinforced concrete beams were
manufactured. Among these, eight were solid beams, while the remaining eight were hollow beams, all
featuring rectangular cross-sections. These specimens were constructed employing polyolefin fiber. The
findings indicated that incorporating polyolefin fiber into the concrete mixture led to improved
mechanical properties in the cured concrete. The most significant enhancements were observed in the
splitting tensile strength and flexural strength tests conducted on the specimens. Both solid and hollow
beams exhibited notable enhancements in their torsional performance. These enhancements occurred as
the polyolefin fiber percentage increased from zero to 1.5%, while the transverse and longitudinal
reinforcement ratios remained constant. Furthermore, the reduction ratio of torsional strength becomes
more noticeable when comparing solid and hollow sections in high-strength beams, as opposed to
normal-strength beams.

This study aims to test a concrete specimen with replacement partially of 15 % of the coarse
aggregate by pieces of tires and volcanic aggregates and reduce 5% of the water/cement ratio by substituting
with 4% percentages of styrene butadiene rubber (SBR) and 1% of superplasticizer. The main concrete
components (cement: sand: gravel) were used in weight ratios (1:1.5:3) and a water to cement 0.45 was used
and it was considered as a reference sample (Mix1). A water to cement ratio 0.40 was depended for the
modified mixtures. Samples were cast for testing the compression strength with sizes 150 ×150 ×150 mm for
ages 7 and 28 days. the absorption rate, with a size of 100 ×100 ×100 mm at age 28 days. Moreover, 150
×150×150 mm for depth of penetration test at the age of 28 days.
Briefly, the observed results were exhibited that the partial replacement of normal aggregate in concrete with
volcanic aggregate affects negatively on the workability, so 4% of the polymer SBR and 1% of the
superplasticizer have improved the workability. The improvement in the workability of concrete contributed
to reducing the ratio of water to cement required for mixing compared to ordinary concrete, and this in turn
led to an improvement in performance of hardened concrete. In addition, the reduction of the permeability
level. The results also illustrated that the replacement of the gravel in the modified mixtures (Mix 3 and Mix
2) reduces the weight of hardened concrete by (10-12%) and (7-9%) compared with conventional concrete,
respectively, which makes it suitable for use in mediumweight concrete applications.
Moreover, it can be concluded that the strength properties of the modified mix with volcanic aggregate
improved by 19-20% compared to that of the unmodified concrete. While the modified concrete by cutting
tires showed significant deterioration in the concrete's resistance 21% despite the reduction of concrete
permeability.