Designing a Stand for Machine Tool Energy Efficiency, With Pump Embodied Energy Tradeoff Case Study

Energy consumption of machine tools needs to be investigated and decomposed to determine areas for improvement. Motors are one key area of energy consumption, and the analysis of motors, including pump motors is useful for long term energy saving. The following paper describes the static and dynamic analysis of a machine tool stand and an energy analysis to compare manufacturing the stand against using the pump motor. The stand needed to be designed that would both withstand the static load of the machine and minimize vibrational excitation caused during grinding experiments. A review of life cycle inventories for induction motors was then undertaken to evaluate the manufacturing energy consumption of pump motors. A breakeven time was determined for the energy investment of replacing a coolant pump with a stand to conserve energy via gravity-fed coolant recirculation. The simulations were performed as worst-case scenarios and are not necessarily indicative of regular use. Results indicate that the stand as designed will not transmit any significant harmonic vibrations. Results of the energy comparison identify that fractional horsepower coolant pumps operating continuously can be replaced with a stand and the energy to produce the stand will break even within two to three years depending on operating schedule.

Experimental and numerical investigations on longitudinal vibration of suspended monorail trains induced by bogie pitching motion

The longitudinal harmonic vibrations found in the suspended monorail train (SMT) seriously affected the ride quality and dynamic behaviour. In this work, the experimental and simulated analyses are carried out to reveal the essential phenomenon, occurring mechanism and possible solutions to this issue. Firstly, the ride quality and vibration transmission of the tested SMT system are investigated. It is found that the longitudinal vibrations with the frequency of 2.7Hz occur to the carbody, bogie frame and suspension of the train system. Due to the secondary suspension is lower than the gravity center of the bogie frame, the bogie pitch motion with low damping ratio can be easily excited. The longitudinal components of the bogie pitch motion will transfer to the carbody and wheelset through traction rod and primary suspension, respectively. After that, the multibody dynamic model of a suspended monorail train is developed. Based on the numerical model, some parametric simulations, e.g. rubber stiffness, traction rod height and secondary damping, etc., are carried out to propose solutions to relieve the longitudinal vibrations. Finally, the field tests for the SMT arranging the longitudinal dampers are conducted to verify its improvement to longitudinal vibrations.

CALCULATION OF PARAMETERS OF BRANCHED MECHANICAL SYSTEMS WITH HARMONIC VIBRATIONS. Continuation

Parallel-series and series-parallel connections of mechanical power consumers are considered. According to the known parameters of systems and the disturbing harmonic effect, the velocities of the elements of mechanical systems and the forces applied to them are algebraically determined. For the considered branched mechanical schemes, the classical methods based on solving second-order differential equations become many times more complicated and require solving systems of equations that reduce to higher-order differential equations. The use of a symbolic (complex) description of mechanical processes and systems makes it possible to use instead simple and compact algebraic methods, the complexity of which is ten times less. Vector diagrams, not being a necessary component of the study of mechanical systems, are of significant methodological importance, since they show quantitative and phase relationships between the parameters of systems.

CALCULATION OF PARAMETERS OF MECHANICAL SYSTEMS WITH HARMONIC VIBRATION

Parallel and series connections of mechanical power consumers are considered. According to the known parameters of systems and the disturbing harmonic effect, the velocities of the elements of mechanical systems and the forces applied to them are algebraically determined. Attention is paid to resonant modes, incl. resonance of forces and resonance of speeds. The use of a symbolic (complex) description of mechanical systems with forced harmonic vibrations (in a steady state) made it possible to abandon the extremely cumbersome and laborious calculation algorithm associated with solving differential equations and replace it with simple and visual algebraic operations. Due to this, the calculation time is reduced significantly. Vector diagrams, not being a necessary component of the study of mechanical systems, are of significant methodological importance, since they show quantitative and phase relationships between the parameters of systems.

Pengembangan Modul Praktikum Fisika Berbasis Open Ended Problem Pada Pokok Bahasan Getaran Harmonis

This study aims to develop and test the feasibility of physics practicum modules based on open ended problems on the subject of harmonic vibrations. This research type is research and development (R & D) by Sugiyono using 8 stages, namely potential and problems, data collection, product design, validation of practicum modules, improvement of practicum modules, practicum module trials, revision of practicum modules, and final products. The feasibility test for practicum module based on open ended problem uses a Likert scale questionnaire with validation by two validators. Research subjects MIPA MAN 5 Cirebon students, amounting to 9 students. The instrument used in the form of practical modules and questionnaire responses of students. The results of this research and development analysis were produced by practicum module products based on open ended problems on the subject of harmonic vibrations with an average validator score of 5.00 or (100%) with the Very Good (SB) category and the average score of students 4, 02 (80.40%) included in the Good category (B). So it can be concluded that the development of physics modules based on open ended problems is feasible to be used as practical teaching materials.