Optimization and fast prototyping of polymer parts exposed to cyclic loading

Many mechatronic systems operate with parts made of polymers. This cost-effective solution is also easy to design. Manufacturing is trivial for producers who produce millions of parts. The solution is more complicated when the fatigue and loading is a significant factor. The paper describes the development of polymer parts that are loaded by cyclic operation. The number of cycles in a specific application can be around 1 million. The specific case also deals with a corrosion environment around these components. Gasses in the environment cause degradation of material and failure of parts made of specific polymers. This interaction limits the choice of suitable materials. The mechanism operates in two directions which define the opening of a valve and free turn. Two variants of elastic valves were analysed. Loading states were simulated by final element methods. Internal stresses and contact stresses were analysed. Results were compared with long-term test results. The material creep and other material properties define the function of elastic parts after thousands of cycles. The technology of mould fabrication was analysed considering simplification and general effectivity of production. Prototype valves were printed by FDM 3D printer and tested. Prototype moulds were printed by SLA 3D printer, which produces high-temperature stable polymer. This procedure shows cost-effective prototype development and test procedures.

Modeling Battery Connections in the Electronic Lab

The paper deals with the modeling of the processes of charge-discharge of battery assemblies taking into account their degradation. The results of simulating the cyclic operation of battery assemblies in the Electronics Workbench electronic laboratory are presented, possible schemes of inclusion are given, and options for re-switching batteries during operation are considered as well as connecting additional elements to extend the life of the connection. The simulation took into account the presence of one defective battery in the assembly. The operation of the assembly with a defective battery and a reference battery was compared. As a result of the analysis of parallel-serial and serial-parallel battery connections, the first one is considered preferable. For an assembly with a parallel-serial connection, the time parameters of operation remained almost unchanged, but the differences in the voltages of the defective and other batteries changed more than twice as compared with a serial-parallel connection. The changes in charge, voltage and current of assemblies with a degraded battery and a reference battery are analyzed. Timing diagrams are shown for batteries connected in parallel and in series with defective batteries. Power losses in a defective battery are reduced by choosing a parallel-series assembly, while switching a connection from a serial-parallel connection to a parallel-series one does not lead to compensation for the degradation of battery parameters. Changing the switching time intervals in a wide range does not contribute to increasing the capacity of a defective battery. Degradation of battery parameters leads to sharper surges in voltage, charge and current. The additional power recharge of the defective battery maintains the performance of the entire assembly. Recharge can be performed by connecting in parallel a defective additional battery or a capacitor, which is equivalent to replacing a degraded battery with a new one.

Thermal Profiling of Automotive Turbochargers in Durability Tests

A major portion of the development of an automotive powertrain system is devoted to robustness and durability testing to ascertain the viability of the design. For turbochargers, thermo-mechanical fatigue is often considered as life limiting failure mechanism for the turbine section, therefore, these tests involve repeated and continuous cycling of the turbocharger for hundreds of hours. The Thermal History Coatings (THC) can offer a new and unique solution. THCs are applied to the surface of a component and, when heated, the coating permanently changes according to the maximum temperature of exposure. The technique has been used in several turbomachinery, and other applications to capture the spatial temperature distribution of critical components. However, the turbocharger durability test presents new challenges for the technique. It has not been tested in this type of application and repeated cycling operation can test the response of the coating on the temperature measurements. In this paper, the capability of the THC for this application was investigated. For the first time, the effect of cyclic operation on the THC is reported. The measurement capability was demonstrated on two turbine housings tested on a gas stand, one for a single cycle, another for 10 cycles. The results show that the surface temperature profile of the two turbine housings can be accurately recorded and the results are validated against the installed thermocouples. The demonstration indicates that the THC can be used to acquire accurate and detailed spatial temperature distributions. This information improves the interpretation of a durability test.

Theoretical Study on a Novel Temperature Breakpoint Cyclic Operation to Enhance Desiccant Packed Bed Performance

In a conventional desiccant packed bed dehumidification, the adsorption and desorption operations switched at a constant cycle. However, this Conventional Steady Cyclic (CSC) operation was not performed well under disturbances. Therefore, a Temperature Breakpoint Cyclic (TBC) operation is proposed. A numerical model of the desiccant packed bed dehumidification system has been constructed and validated. The model was then used to assess the desiccant packed bed dehumidification performances in term of moisture removal capacity (MRC) and dehumidification coefficient of performance (DCOP) under various cycle times and temperature factors. The calculation results showed that under CSC, larger amounts of energy were required in the desorption operation, while the TBC exhibited higher performances in term of both MRC and DCOP. Notably, at a high regeneration temperature, the MRC of the TBC was 10% higher than the CSC’s; moreover, the DCOP of the TBC was twice higher than the CSC’s. In other words, at high recovery temperature, both operations exhibited comparable capacities while the energy cost was halved under TBC operation.

Agree, Move and the Scope of the Phase Impenetrability Condition

This paper addresses a certain contradiction in the application of the Phase Impenetrability Condition (PIC) to domains involving the long-distance Genitive of Negation (GoN) and wh-movement in Polish. It appears that in syntactic domains of the tensed sentence including an infinitive complement, there is a tension between a long-distance dependency (holding between NEG in the main clause and the embedded object in genitive) and a cyclic operation of wh-movement. The operation of wh-movement, a classic example of Chomsky’s Move, observes cyclicity and the PIC, judging by the standard tests based on reconstruction (Chomsky 1995; Heycock 1995; Fox 1999; Safir 1999; Legate 2003; Witkoś 2003; Lebeaux 2009), while the Agree-based case marking requires the PIC to be inoperative in exactly the same context and in the same domain. Both operations place contradictory requirements on the PIC, which implies that this condition does not apply to them in the same manner: it always holds of Move but does not always hold of Agree.

Oil submersible pumps reliability during cyclic operation

The ESP reliability analysis was conducted to determine the correlation between ESP operation mode and ESP component reliability. The analysis was based on operation data of more than 700 ESP. The reliability of operating mode-dependent ESP components was analyzed. ESP and seal section test results under cyclic and constant operation conditions were shown. As a result, it was determined that periodic operation negatively affect ESP components lifetime. Recommendations for ESP cyclic operation were proposed.