This paper is a review of the literature about CFD modeling and analysis of journal, thrust, and aerostatic bearings; the advantages and disadvantages of each are specified, and the bearing problems that have been analyzed are discussed to improve their designs and performance. A CFD transient analysis of journal bearings was conducted using the dynamic mesh method together with movement algorithms while keeping a structured mesh of a good quality in the ANSYS Fluent software to determine the equilibrium position of the journal and calculate the dynamic coefficients. Finally, areas of opportunity for analyzing and designing fluid film bearings to improve their performance are proposed.

Nowadays, the use of biomechanical devices in medical processes and industrial applications allows us to perform tasks in a simpler and faster way. In the medical field, these devices are becoming more and more common, especially in therapeutic applications. In the design and development of orthopedic devices, it is essential to consider the limbs’ kinematic, kinetic, and anthropometric conditions, as well as the implementation of control strategies (robust, PID, fuzzy, and impedance, among others). This work presents a virtual prototype of a knee orthosis and the implementation of a control system to follow a desired trajectory. Results are presented with the virtual prototype through a co-simulation between MSC Adams and MATLAB Simulink with fuzzy control, virtually replicating the gait cycle.

En este trabajo se presenta una revisión exhaustiva de los diferentes tipos de amortiguadores regenerativos utilizados para mejorar la reducción del consumo de combustible y de las emisiones contaminantes (principalmente el CO2) en vehículos comerciales. En primera instancia, se describe la interacción entre el tren motriz y el sistema de suspensión automotriz, incluyendo los ciclos de velocidad de conducción como el enlace principal. Posteriormente, se presenta un esquema gráfico del proceso de regeneración de energía vibratoria mediante amortiguadores regenerativos, considerando el sistema de almacenamiento de energía. Además, se discuten los avances tecnológicos recientes de los diferentes tipos de amortiguadores regenerativos, sopesando principalmente la filosofía de diseño del mecanismo de rectificación de energía vibratoria. Finalmente, se presentan las conclusiones y tendencias futuras sobre las aplicaciones de estos dispositivos en diferentes disciplinas de la ingeniería.

This work focused on the design, development and construction of a new low cost soldering iron that works by means of induction heating. The amount of electronic components has been minimized in order to reduce production costs. Additional tests were undertaken to determine the ideal tips for soldering, and the adaptations necessary to guarantee self-regulation using a nickel foil shield (due to its low curie temperature) are suggested. The new device contains a resonant inverter able to generate alternating magnetic fields of 100 kHz at the center of an 18-turn coil; the inverter is controlled only using an astable oscillator circuit. The paper examines criteria to select suitable soldering-tips by experimentally determining their equivalent resistance heating it within the resonant inverter or well, another one by using a rapid magnetic test. The system represents a good tool, suitable for the manufacture of development boards or electronic tasks.

The vibration control in structural design has long been a critical area of study, particularly in mitigating undesirable resonant vibrations using dynamic vibration absorbers (DVAs). Traditional approaches to tuning DVAs have relied on complex mathematical models based on Newtonian or Euler–Lagrange equations, often leading to intricate systems requiring simplification of the analysis of multi-degree-of-freedom structures. This paper introduces a novel modeling approach for analyzing DVAs based on the concept of global admittance, which stems from mechanical admittance and network simplifications. This model streamlines the representation of structures with DVAs as one-degree-of-freedom systems coupled with a global admittance function, which emulates additional damping coupled to the primary structure. In this work, global admittance functions are determined by the independent analysis of the mechanical networks of the DVA, restructuring the process of obtaining the system’s transfer function. The model was validated using different classical DVA configurations, demonstrating total accuracy in its applicability across designs concerning conventional modeling. Our most remarkable finding was that the dimensionless function, ${\gamma }_g\left(\mathsf{\Omega }\right)$, resulting from the global admittance, partially decouples the dynamics of the DVAs from the primary structure, facilitating the implementation of passive vibration control strategies in more realistic structural models. Additionally, this work establishes a significant advancement in vibration control analysis, providing a flexible tool for control strategies in real-world structural systems.

Nowadays, the inerter device has become one of most popular mechanical devices in the vibration absorption field for both stationary and non-stationary mechanical structures. One of the problems commonly reported in the literature is the force transmission control in the foundations that support the machines, which is generally addressed by using either isolators or classic dynamic vibration absorbers (DVAs). However, the mechanical energy dissipation capability of these two solutions is still limited. This work focuses on improving the control performance for the conventional absorber using the inerter’s inertial mass amplification and negative stiffness effects. In order to fairly evaluate the control performance of the DVA based on grounded inerter, the and optimization criteria are proposed. When the dimensionless frequency response function (FRF) of the transmissibility is minimized at the resonant peaks, the criterion reveals an improvement of 29.74% in mitigating harmonic vibration. Finally, the total vibration energy transmitted to the foundation is minimized via criterion that provides an improvement of 33.03%. Hoy en día, el inersor se ha convertido en uno de los dispositivos mecánicos más populares en el campo de absorción de vibración tanto en estructuras mecánicas estacionarias como no estacionarias. Uno de los problemas comúnmente reportados en la literatura es el control de transmisión de fuerza en los cimientos que soportan a las maquinas, que generalmente se atacan utilizando ya sea aisladores o absorbedores dinámicos de vibración (DVAs). Sin embargo, la capacidad de disipación de energía mecánica de estas dos soluciones es aún limitada. Este trabajo se centra en mejorar el rendimiento de control del absorbedor convencional utilizando los efectos de amplificación de masa inercial y el de rigidez negativa del inersor. Para evaluar justamente el rendimiento de control del DVA basado en inersor conectado a tierra, se proponen los criterios de optimización y . Cuando se minimiza la función de respuesta en frecuencia adimensional de la transmisibilidad en los puntos resonantes, el criterio revela un mejoramiento del 29.74% de atenuación de vibración. Finalmente, se minimiza la energía total de vibración transmitida a los cimientos a través del criterio que proporciona un mejoramiento del 33.03%.