Prosjekt H.J.O.R.T

Bakgrunnen for denne bachelor oppgåva var å finne ei løysning på problemstillinga rundt hjortepåkøyrslar. Etter oppdrag frå Statens Vegvesen blei det spesifikke testområdet ved hjortegjerdet på Myrmel, mellom Lunde og Sande. Prosjektet arbeidet blei delt opp i to delar. Den eine delen var å undersøkje sensorar og moglegheitane for å detektere hjorten samt rapportere dataen vidare til database på server. Dette i tillegg til å planleggje med oppdragsgjevar og samarbeidspartnarar, NAF og Tryg Forsikring. Den andre delen gjekk ut på å teste om den føreslegne løysninga fungerte i praksis, dette ved å ha ein testperiode der vi fortlaupande analyserte utstyret og resultata og gjorde eventuelle endringar eller forslag til framtidige utbetringar. Resultatet av prosjektet var eit system som var bevist fungerande, men med mykje potensial for utbetring. Systemet var ikkje i god nok standard til å settast i full drift i trafikken, men prosjektet har lagt grunnlaget for noko som kan vere med på å revolusjonere sikkerheita på veg

Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR) system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when utilizing heat from the exhaust gas recirculation system of a truck engine. The results showed that the boiler’s pinch point necessitated trade-offs between maintaining adequate boiling pressure while achieving acceptable cooling of the EGR and superheating of the water. The expander used in the system had a geometric compression ratio of 21 together with a steam outlet timing that caused high re-compression. Inlet pressures of up to 30 bar were therefore required for a stable expander power output. Such high pressures increased the pump power, and reduced the EGR cooling in the boiler because of pinch-point effects. Simulations indicated that reducing the expander’s compression ratio from 21 to 13 would allow 30% lower steam supply pressures without adversely affecting the expander’s power output

Dynamiskt belastade tribologiska system under plastisk formning, del II --- analyserade genom akustisk emission

The dynamic friction process and contact surface between tool and working material in a plastic forming process is hard to describe in mathematical form and hard to monitor and control in real time. High production speed and highly optimised forming operations result in great demands on the control equipment. Especially if the influence from variations due to the tool, work material and the friction surfaces between working material and tool can not be minimised and are essential for the quality of the product. Friction surfaces can be monitored with acoustic emission (AE) and the AE-signal depends on the lubrication between the friction surfaces. The power of the AE-signal increases with ungreased friction surfaces compared in more effectively lubricated surfaces. Differences in detected acoustic emission between different lubricants can be measured and this information can be used to classify different lubricants and the performance in the investigated forming operation. Acoustic emission from a forming operation contains measurable information from events as galling (welded work material on tool), wear of tool, penetration of lubricant, stick-slip, wrinkling necking of sheet material and cracking in tool-material or working material. The detected acoustic emission is directly proportional to the mechanical power consumption in a friction surface and can therefore be used to estimate the forces on the friction surfaces. A change in the tribological parameters, as material in contact, the efficiency of lubricants, the roughness of the friction surfaces, relative velocity between the friction materials and contact pressure can be monitored with acoustic emission. Mounting and adjusting of tool parts or correction of holding forces in deep drawing operations can be optimised by minimising acoustic emission due to influence of boundary layer friction and wrinkling. Critical friction surfaces can be monitored with consideration to the wear of the friction surfaces. The momentary acoustic emission contains information about the status of wear at the friction surfaces and if the wear is a wear-in or a wear-out process. A further development of the acoustic emission monitoring, primarily regarding methodology, the performance of the measurement equipment and methods of analysing measured data, should lead an increased implementation of the method, measuring and monitoring different forming operations and production lines. This will in the end result in new ways to increased production quality and improved quality check. This work is divided in two volumes, ''Dynamically loaded tribo-systems in plastic forming operations, part I --- actuated by cyclic mechanical stress'' and ''Dynamically loaded tribo-systems in plastic forming operations, part II --- monitored by acoustic emission''. Part I deal with the subjects magnetostrictive actuators, vibration actuated tribosystems and vibration assisted wire drawing. Part II deals with the monitoring of tribosystems using acoustic emission

Forming and trimming of 2-mm thick DP600 sheet steel in tools and dies 3D-printed in maraging steel by laser-based powder bed fusion

In a previous investigation, 3D-printed solid and topology optimized semi-industrial tools for forming and trimming of 2-mm thick hot-dip galvanized DP600 were certified. This certification required 50,000 strokes in U-bend forming and 100,000 strokes in trimming/cutting/blanking. The present paper focuses on the tool wear, the U-bend sheet surfaces, the shear and fracture zone lengths in trimming, and the punch forces in this certification. The 3D-printed tools behave as conventional tools do. Although small, there seems to be a difference in wear at the profile radius between the solid and topology optimized U-bending tool halves 3D-printed in maraging steel DIN1.2709

Static and Dynamic Friction Processes Under the Influence of external Vibrations

The influence of external vibrations on the frictional force has been studied, using different frequencies, amplitudes, loads and materials. The results show that it is possible to affect the frictional force between two surfaces in contact through vibration. The frictional force can be weakened chiefly through a separation of the surfaces or strengthened by welding phenomena in the contact surfaces. Experiments have shown that either an increase or a decrease in the frictional forces can be obtained when one of the parameters, surface pressure, frequency or amplitude, is changed. Surface roughness, vibration direction, relative speed and materials may also play a determining role. With vibration assistance, the tendency to stick-slip is decreased or eliminated

Indication of cracking during pressing of advanced thin plates using an AE-based monitoring system

The acoustic emission that is detectable in the forming of complex thin part plates contains information about the quality of the pressed plates. The information can be used as process control and to filter out advanced thin plates with defects such as cracks. The article describes the results obtained in a try-out pressing process in special developed punch-die pairs with different pressing depths in a press at Alfa Laval in Lund. At the trials two module testing tools called SE30 and SE25 were used to create a different degree of formability by different surface enlargement in the same complex original design. Used sheet materials were stainless steel and two qualities of titanium. The used measuring system was based on a PC with AE-sensor of model 8152 from Kistler. The results of experiments show that it is possible to detect and distinguish the plates that fracture during the forming operation. For a large number of plates detectable signals from areas close to cracks with only local necking were also obtained. This local necking cannot or can hardly be detected by light-test or light detecting equipment. The left figure shows a metal sheet with fractures and the right figure describes measured acoustic emission as a function of time and the number of the details. In this example the first four plates are fractured and the last five plates are without any fractures. There are several differences between the two types of signals of acoustic emission. The signal that indicates cracking of the plate differs by a sudden high acoustic emission and also a slightly lower level before the crack formation is started. Before the fracture occurs the sheet metal is stretched out and the lower level of acoustic emission also indicates less movement of the sheet metal just before the time of fracture. The purpose of the conducted experiment was to find out whether the selected approach was appropriate. The obtained result shows unambiguously that the chosen approach is pertinent and that an AE-based monitoring system can be used as a process control system to ensure the quality of production of advanced thin plates in stainless steel and titanium. Information can be saved from the main forming operation and can be used to see trends both long and short term

A non-invasive approach to study lifetime exposure and bioaccumulation of PCBs in protected marine mammals: PBPK modeling in harbor porpoises

In the last decade, physiologically based pharmacokinetic (PBPK) models have increasingly been developed to explain the kinetics of environmental pollutants in wildlife. For marine mammals specifically, these models provide a new, non-destructive tool that enables the integration of biomonitoring activities and in vitro studies. The goals of the present study were firstly to develop PBPK models for several environmental relevant PCB congeners in harbor porpoises (Phocoena phocoena), a species that is sensitive to pollution because of its limited metabolic capacity for pollutant transformation. These models were tested using tissue data of porpoises from the Black Sea. Secondly, the predictive power of the models was investigated for time trends in the PCB concentrations in North Sea harbor porpoises between 1990 and 2008. Thirdly, attempts were made to assess metabolic capacities of harbor porpoises for the investigated PCBs. In general, results show that parameter values from other species (rodents, humans) are not always suitable in marine mammal models, most probably due to differences in physiology and exposure. The PCB 149 levels decrease the fastest in male harbor porpoises from the North Sea in a time period of 18†years, whereas the PCB 101 levels decrease the slowest. According to the models, metabolic breakdown of PCB 118 is probably of lesser importance compared to other elimination pathways. For PCB 101 and 149 however, the presence of their metabolites can be attributed to bioaccumulation of metabolites from the prey and to metabolic breakdown of the parent compounds in the harbor porpoises