Essam Lauibi Esmail

Compound power-splitting mechanisms (CPSMs) are inadequately studied due to closed-loop kinematic models limitations and lonely computational tools for exploring huge configuration spaces. This study proposes a symbolic and computational framework to kinematically analyze, classify, and assess the performance of comparable continuous passive motion systems (CPSMs) that harness dual planetary gear trains (PGTs). In MATLAB, the technique automatically obtains symbolic expressions for the speed ratio function as a function of gear parameters (for instance, pinion tooth count) opening up the quick enumeration of potential structures. In this work, we generated 144 CPSM configurations and classified their motion regimes for twelve classes according to the speed constraints. We also assess performance across a dense range of parameters, filtering out singularities and infeasible regions, and visualize feasible solutions as 3D maps of the leading speed ratio. Structurally, the 30 combined power splitting mechanisms with |R_(z,y)^j |> 25, and 18 with |R_(z,y)^j |> 25 and R_(z,y)^x> 1 represent commonalities indicative of torque amplification/motor coordination. The patented CPSM serves to validate the model, confirming prediction accuracy. The framework is a high-level method to categorize and synthesize multi-planetary mechanisms found in automobiles, industrial robotics, and power transmission.

This paper presents a comprehensive study on the structural synthesis and classification of planetary gear mechanisms (PGCMs), which combine the advantages of planetary gear trains (PGTs) and cam mechanisms to produce precise, intermittent, or variable-speed motions. These mechanisms are particularly suitable for high-performance industrial applications, such as indexing tables, path generation systems, and rigid body guidance. The work begins by detailing the kinematic and structural characteristics of PGCMs and identifying possible configurations based on degrees of freedom, link types, and joint arrangements. Using graph theory, rooted graph representations are developed to systematically enumerate two-degree-of-freedom PGCMs, up to seven links. A spanning-tree-based synthesis method is used to generate candidate structures, followed by genetic compatibility analysis to identify viable PGCM configurations. The proposed method produces a set of functionally and structurally distinct PGCMs, including a novel five-link mechanism that achieves precise path generation with minimal complexity. This study not only enhances the theoretical framework for PGCM design, but also provides a practical basis for its application in modern mechanical systems.

Planetary gear mechanisms (PGMs) are commonly employed in mechanical applications. Graph theory is a useful tool for synthesizing PGM structures to develop new transmission systems. The synthesis of 1- and 2-degree-of-freedom (DOF) planetary gear trains received a lot of attention. Nevertheless, the synthesis results are inconsistent because previous graph representations were insufficient for the synthesis processes. This paper proposes a graph model that improves upon earlier models, introducing the concept of type-2 pseudo-isomorphic graphs. The vertex levels are used to construct PGM-spanning trees and define geared graphs. This approach avoids pseudo-isomorphic graphs and maintains a one-to-one correspondence between PGM elements and the graph. The 6-link 2-DOF PGM synthesis demonstrated the current graph representation, yielding 24 non-isomorphic mechanisms of 11 or more than previously reported. Possible explanations for the inconsistency of synthesis results with earlier studies are investigated, and the advantages of the modified graph over existing approaches are discussed in detail.

This study has been explored the enhancement of the mechanical, physical, and thermal properties of a polymeric matrix by incorporating fiberglass, multi-wall carbon nanotubes (MWCNTs), and also, their hybrid combinations. Composite materials have been fabricated with different filler concentrations and have been evaluated for tensile strength, thermal conductivity, compressive strength, and the coefficient of thermal expansion (CTE). The results have shown that the addition of 3 wt% of the glass fibers has significantly increased the compressive strength by approximately 29%, while 3 wt% of the MWCNT effectively maintains the tensile strength and significantly improves the thermal conductivity and dimensional stability. The incorporation of the MWCNT has increased the thermal conductivity by 125% and has significantly decreased the CTE, indicating limited mobility of the polymer chain, and has improved the thermal performance. Conversely, the hybrid composites did not exhibit synergistic effects and often performed poorly compared to the single-reinforcement systems. Because of the poor dispersion and agglomeration of nanoparticles, in addition to interface mismatch, the results for each type of reinforcement demonstrated distinct advantages and emphasized the need for improved processing strategies to achieve functional synergies in hybrid nanocomposite materials for various applications.

Electric vehicles (EVs) are known for their power efficiency and lower pollution levels compared to traditional vehicles. The design of dual-motor EV systems, utilizing planetary gear trains, is a significant area of research. The impact of power circulation on losses in novel and patented planetary gear mechanisms has not been extensively explored in previous configuration design studies, despite its importance as a key component of the mechanism. Accurately understanding the power distribution in a dual-motor system seems to be crucial for fully comprehending an invention. This paper explores the positive aspects and drawbacks of PGT configuration, with a focus on efficiency, which may affect competitiveness in real-world applications. If power flow estimation is not possible or if operating constraints prevent it, it is likely that the patent was not thoroughly examined or the inventor lacked experience in the subject matter. A nomograph is a graphical tool used to analyze the relationships between variables in power-split systems, including power flow and efficiency. A systematic approach is proposed for evaluating the performance and power loss of PGTs. Analytical formulas for powers, losses, and efficiency are derived. A parametric study on a wheel hub motor reveals that a higher gear ratio enhances efficiency and performance, with power flow analysis indicating power circulation and amplification. Controlling gear ratios precisely can change power flow direction, enhancing efficiency. Criteria for no power circulation are established, leading to a new configuration.

The Rubber-carbon black composite material-based product is the main matrix used in domestic and industrial applications in the last decades. This study proposes replacing the reinforcing carbon with matrix-neutral rubber with epoxy resins to reduce the carbon footprint and lower the environmental impact while enhancing the product's mechanical properties. Five additive percentages of carbon--epoxy, starting from 100-50% Carbon-black and 0-50% Epoxy, were studied using a hybrid experimental-numerical approach. Experimentally, the extension fatigue, flexural fatigue, and elongation modulus testing were completed using the universal testing machines with a low loading rate (quasi-static process). Numerical, the finite element analysis by the commercial software ABAQUS-SAE within the built-in hyperelastic constitutive model was utilized to visualize the full-field stresses. The experimental nominal stress-strain data was used as input for the numerical model, and Ogden's formula was applied to simulate the mechanical response of the specimens. The stress field and stress concentration of different experimental tests are given. The effect of increasing the additive epoxy on the rubber-carbon mechanical response and the fatigue life under repeated loads were identified and discussed. Furthermore, the results show that a small amount of epoxy can be used as a reinforcing material for a rubber compound and it improves the mechanical properties. This along with more results are shown in the result section

Planetary gear trains (PGTs) structural synthesis can aid in the evolution of novel transmission systems in machinery. The synthesis of 1-DOF PGTs has received a lot of attention over the last half-century. However, the majority of works on PGT synthesizing are limited to single-planet gear trains. Based on parent graphs and permutation group theory, this article describes a systematic technique for synthesizing PGTs. To begin, we define the PGT adjacency matrix. Then, using the permutation groups, we propose an algorithm for assigning values to adjacency matrix elements to generate the characteristic equations. The characteristic equation for each family is determined in order to synthesize 1-DOF graphs. These equations result in no isomorphic configurations being generated. The link assortments for seven-link 1-DOF PGTs are generated automatically. Finally, for each link assortment family, parent graphs are synthesized. To the best of our knowledge, the synthesis method of the 7-link 1-DOF PGT is a novel method that has not yet been published in the literature.