A mechatronic system of actuators, sensors, and analog circuits is demonstrated to control the self-excited oscillations known as chatter that occur when single-point turning a rigid workpiece with a flexible tool. The nature of this manufacturing process, its complex geometry, harsh operating environment, and poorly understood physics, present considerable challenges to the control system designer. The actuators and sensors must be rugged and of exceptionally high bandwidth and the control must be robust in the presence of unmodeled dynamics. In this regard, the qualitative characterization of the chatter instability itself becomes important. Chatter vibrations are finite and recognized as limit cycles, yet modeling and control efforts have routinely focused only on the linearized problem. The question naturally arises as to whether the nonlinear stability is characterized by a jump phenomenon. If so, what does this imply for the "robustness" of linear control solutions? To answer our question, we present an advanced hardware and control system design for a boring bar application. Initially, we treat the cutting forces merely as an unknown disturbance to the structure which is essentially a cantilevered beam. We then approximate the structure as a linear single-degree-of-freedom damped oscillator in each of the two principal modal coordinates and seek a control strategy that reduces the system response to general disturbances. Modal-based control strategies originally developed for the control of large flexible space structures are employed; they use second-order compensators to enhance selectively the damping of the modes identified for control. To attack the problem of the nonlinear stability, we seek a model that captures some of the behavior observed in experiments. We design this model based on observations and intuition because theoretical expressions for the complex dynamic forces generated during cutting are lacking. We begin by assuming a regenerative chatter mechanism, as is common practice, and presume that it has a nonlinear form, which is approximated using a cubic polynomial. Experiments demonstrate that the cutting forces couple the two principal modal coordinates. To obtain the jump phenomena observed experimentally, we find it necessary to account for structural nonlinearies. Gradually, using experimental observation as a guide, we arrive at a two-degree-of-freedom chatter model for the boring process. We analyze the stability of this model using the modern methods of nonlinear dynamics. We apply the method of multiple scales to determine the local nonlinear normal form of the bifurcation from static to dynamic cutting. We then find the subsequent periodic motions by employing the method of harmonic balance. The stability of these periodic motions is analysed using Floquet theory. Working from a model that captures the essential nonlinear behavior, we develop a new post-bifurcation control strategy based on quench control. We observe that nonlinear state feedback can be used to control the amplitude of post-bifurcation limit cycles. Judicious selection of this nonlinear state feedback makes a supplementary open-loop control strategy possible. By injecting a harmonic force with a frequency incommensurate with the chatter frequency, we find that the self-excited chatter can be exchanged for a forced vibratory response, thereby reducing tool motions. / Ph. D.

The work presented is a master’s thesis at the track Machine Design at KTH Royal Institute ofTechnology. The project was commissioned by Epiroc AB through Svea Teknik AB. Epiroc’s Easer L is a highly versatile and flexible mobile raise boring machine used to drill opening holes and media holes. A drill string handling system is used to construct and deconstruct the drill string during a raise. Currently, the Easer utilizes a lifting arm to move the drill string components between a pipe rack and the derrick. A pipe loader, which is a second arm mounted on the derrick, is used to align the components with the drill string. This work aims to examinethe possibility to replace this system with a more compact and preferably automatable solution. The work had its main focus on a concept generation and evaluation process, where a wide range of possible means of handling the drill string handling system’s sub functions were methodically mapped in function means trees. Several concepts were synthesized using a morphological method and brain storming in a diverging process and their variants were explored and mapped. An iterative screening process utilizing a Pugh Matrix and GATEs converged the ideas until a final concept selection was performed. The resulting conceptual drill string handling system consist of a new crane and gripper solution and a new pipe loader, all modified to lift pipes horizontally instead of vertically. The pipe racks were modified to enable better interaction with the gripper module, even if racks are inclined. A sliding mechanism was integrated in the crane mounting bracket to eliminate the need for remounting the crane, reducing down times. The resulting conceptual drill string handling solves many of the challenges of the existing system and increases the flexibility, automation and productivity of the Easer L. / Detta är ett examensarbete på masterspåret Maskinkonstruktion på Kungliga Tekniska Högskolan. Arbetet utfördes på uppdrag av Epiroc AB genom Svea Teknik AB. Epirocs Easer L är en mångsidig och flexibel mobil stigortsmaskin som används till öppningshål och mediehål. Borrsträngskomponenternas hanteringssystem används för att gradvis montera och demontera borrsträngen under drift. Dagens hanteringssystem inkluderar en kran med en gripanordning som flyttar borrsträngskomponenter mellan deras förvaringsställning och borrtornet. En borrörsladdare, vilken är en ytterligare arm monterad på borrtornet, används för att placera borrsträngskomponenter i linje med borrsträngen. Arbetet syftar till att undersöka möjligheteratt byta ut detta hanteringssystem mot ett mer kompakt och automatiserbart alternativ. Arbetets huvudfokus låg på konceptutveckling, där ett brett utbud av lösningar på hanteringsystemets delfunktioner kartlades metodiskt i funktions­medelträd. Detta följdes av en divergerande process där syntes av en bred mängd koncept utfördes genom morfologisk metod och idéspåning och konceptens variationer kartlades noggrant. En iterativ gallringsprocess kovergerade antalet koncept med hjälp av en Pughmatris och GATEr tills ett konceptval kunde utföras. Slutresultatet är ett konceptuellt hanteringssystem för borrsträngskomponenter beståendes av en kran och gripenhet med tillhörande borrörsladdare, vilka anpassades för att hantera borrsträngskomponenter i horisontellt läge. Detta möjliggör en mer kompakt arbetsvolym. Förvaringsställningarna modifierades för bättre interaktion med gripenheten, även vid ojämn mark. En linjärenhet integrerades i kranens fästpunkt, vilket gör att kranen inte behöver monteras om vilket tidigare orsakade ställtider. Det nya alternativet löser flertalet problem med det nuvarande hanteringssystemet, vilket gör Easer L mer flexibel och automatiserad och ökar därmed produktiviteten.

Esta tese apresenta um estudo com base em zoneamentos de parâmetros geotécnicos provenientes de sondagens rotativas, realizadas no maciço basáltico, localizado na área das obras de Usina Hidrelétrica de Itaipu (Foz do Iguaçu - PR). Estes zoneamentos foram realizados a partir de interpolação dos dados por meio de krigagem ordinária e equações multiquádricas. Os dados provenientes de sondagens rotativas analisados nesta pesquisa são: Rock Quality Designation (RQD), grau de alteração, grau de consistência e grau de fraturamento. Os métodos de interpolação foram avaliados para o parâmetro de RQD, pois tais métodos apresentam características matemáticas similares, assim, foram comparadas interpolações realizadas com krigagem ordinária e equações multiquádricas, sendo comprovada a similaridade destes métodos com dados reais. Sendo assim, os demais parâmetros, por se caracterizarem como variáveis categóricas e, portanto, discretas, e apresentarem complexidade para realização da análise variográfica dos dados (semivariograma experimental e modelagem do semivariograma), foram interpolados apenas pelo método das equações multiquádricas. A validação dos dados interpolados foi realizada a partir de um estudo de caso relativo ao comportamento hidrogeotécnico do maciço rochoso, o qual é monitorado por piezômetros do tipo standpipe. Esta validação mostrou que os métodos utilizados para obter os zoneamentos e os parâmetros de modelagem considerados foram adequados, pois se verificou alta correlação entre as tendências de comportamento obtidas pelas interpolações dos parâmetros geotécnicos do maciço rochoso e o comportamento revelado pelo conjunto de piezômetros instalados no mesmo local. Este trabalho teve como etapa primordial o levantamento de dados históricos relativos às investigações geológico-geotécnicas da área das obras de Itaipu, a partir destes dados foi composto um mapa interativo de localização dos diferentes tipos de investigação realizados no substrato rochoso e terroso. Tal documento permite uma busca rápida e dinâmica das informações geotécnicas, pois apresenta como referência a própria planta da barragem de Itaipu. Cada ponto de investigação está vinculado ao perfil geotécnico. As investigações utilizadas neste mapa são: sondagem rotativa, sondagem à percussão (SPT), ensaio de cone (CPT) e poço manual. Sendo assim, o resgate das informações históricas obtidas nas campanhas de investigação geotécnica na área das obras de Itaipu, resultou na compilação dos dados de forma digital, em que foi elaborado um conjunto de planilhas com formato capaz de ser utilizado em diferentes Sistemas de Informação Geográfica e de interpolação de dados georreferenciados. / This thesis presents a study based on the zoning of geotechnical parameters resulting from core boring, carried out in the basaltic bedrock located in the area of the Itaipu Hydroelectric Power Plant (Foz do Iguaçu - PR). These zonings were carried out based on the interpolation of the data by means of ordinary kriging and multiquadric equations. The data provided by core boring analyzed in this research are: Rock Quality Designation (RDQ), degree of alteration, degree of consistency and degree of fracturing. The interpolation methods were evaluated for the RQD parameter, since such methods present similar mathematical characteristics; therefore, comparisons were made between interpolations resulting from ordinary kriging and multiquadric equations, demonstrating the similarity of these methods with real data. In this manner, the remaining parameters due to being categorized as categorical variables and, therefore, discrete, and presenting complexity for the execution of the variographic analysis of the data (experimental semi-variogram and modeling of the semi-variogram), were interpolated only by the method of the multiquadric equations. The validation of the interpolated data was carried out on the basis of a case study relating to the hydrogeotechnical behavior of the bedrock mass, which is monitored by standpipe piezometers. This validation showed that the methods employed to obtain the zonings and the modeling parameters chosen were adequate, since a high correlation was verified between the behavior trends obtained by the interpolations of the geotechnical parameters of the bedrock mass and the behavior revealed by the set of piezometers installed in the same site. The primordial stage of this job was the acquisition of historical data relating to the geological-geotechnical investigations in the area of Itaipu Dam. This data served as a starting point for the composition of an interactive map showing the location of the different types of investigations carried out in the rock and earthen masses. The resulting document permit a rapid and dynamic search through the geotechnical information, since it presents as its reference the plan view of the Itaipu dam itself. Each point of investigation is linked to the geotechnical profile. The investigations utilized in this map are: core boring, standard penetration test (SPT), cone penetration test (CPT) and manual pit. In this manner, the recovery of the historical information obtained by the geotechnical investigation the Itaipu Dam area resulted in data compilations in digital format, based upon which, a set of tabular forms was obtained of a type capable of being utilized in different Systems of Geographical Information and of interpolation of geo-referenced data.

Uma implementação computacional baseada nos conceitos da mecânica do contato e no Método dos Elementos de Contorno é desenvolvida para simular a interação entre discos de corte e maciço rochosos. Simula-se o contato considerando-se inicialmente uma superfície potencial de contato que é atualizada durante um processo de carregamento incremental, podendo conter elementos separados, em contato sem deslizamento ou com deslizamento parcial. A cada passo do carregamento incremental estima-se a configuração do modelo e os dados obtidos neste passo serão utilizados como parâmetros no passo seguinte até que todo o carregamento esteja aplicado. O modelo em estudo consiste em dois discos de corte paralelos atuando sobre uma base sólida com característica elástica linear. São feitas duas simulações com os discos de corte. Na primeira delas, compara-se a penetração dos discos utilizando-se como parâmetro os valores calculados em uma análise por elementos finitos. No segundo caso, estuda-se a distribuição de tensões no maciço quando se altera o espaçamento entre os discos para um mesmo carregamento. Além desta análise, duas outras comparações são feitas utilizando como parâmetros soluções analíticas e numéricas de modelos clássicos da mecânica do contato. São estes: cilindro e pilar em base elástica. / A computational implementation based on contact mechanics and on the Boundary Element Method is developed in order to simulate the interaction between disc cutters and rock mass. The contact simulation considers initially a potential contact area which is updated during an incremental load process, in such way the surface can include elements in separation, stick or partial slip. At each incremental load step the configuration of the model shall be evaluated and the values computed at such step are used as parameter to the next load step until the end of the loading process. The investigated model consists in two parallel cutter discs on a flat elastic foundation. In the first simulation the penetration of the discs are studied and the results are compared against a finite element simulation. In the second simulation, the stress distribution in the rock mass is evaluated considering different spacing between the disc cutters by keeping the same load. In addition, two benchmark problems of contact mechanics, such as the cylinder and the flat punch on a elastic foundation, were modeled in order to validate the proposed algorithm. The obtained results were compared against analytical and numerical solutions.

Esta tese apresenta um estudo com base em zoneamentos de parâmetros geotécnicos provenientes de sondagens rotativas, realizadas no maciço basáltico, localizado na área das obras de Usina Hidrelétrica de Itaipu (Foz do Iguaçu - PR). Estes zoneamentos foram realizados a partir de interpolação dos dados por meio de krigagem ordinária e equações multiquádricas. Os dados provenientes de sondagens rotativas analisados nesta pesquisa são: Rock Quality Designation (RQD), grau de alteração, grau de consistência e grau de fraturamento. Os métodos de interpolação foram avaliados para o parâmetro de RQD, pois tais métodos apresentam características matemáticas similares, assim, foram comparadas interpolações realizadas com krigagem ordinária e equações multiquádricas, sendo comprovada a similaridade destes métodos com dados reais. Sendo assim, os demais parâmetros, por se caracterizarem como variáveis categóricas e, portanto, discretas, e apresentarem complexidade para realização da análise variográfica dos dados (semivariograma experimental e modelagem do semivariograma), foram interpolados apenas pelo método das equações multiquádricas. A validação dos dados interpolados foi realizada a partir de um estudo de caso relativo ao comportamento hidrogeotécnico do maciço rochoso, o qual é monitorado por piezômetros do tipo standpipe. Esta validação mostrou que os métodos utilizados para obter os zoneamentos e os parâmetros de modelagem considerados foram adequados, pois se verificou alta correlação entre as tendências de comportamento obtidas pelas interpolações dos parâmetros geotécnicos do maciço rochoso e o comportamento revelado pelo conjunto de piezômetros instalados no mesmo local. Este trabalho teve como etapa primordial o levantamento de dados históricos relativos às investigações geológico-geotécnicas da área das obras de Itaipu, a partir destes dados foi composto um mapa interativo de localização dos diferentes tipos de investigação realizados no substrato rochoso e terroso. Tal documento permite uma busca rápida e dinâmica das informações geotécnicas, pois apresenta como referência a própria planta da barragem de Itaipu. Cada ponto de investigação está vinculado ao perfil geotécnico. As investigações utilizadas neste mapa são: sondagem rotativa, sondagem à percussão (SPT), ensaio de cone (CPT) e poço manual. Sendo assim, o resgate das informações históricas obtidas nas campanhas de investigação geotécnica na área das obras de Itaipu, resultou na compilação dos dados de forma digital, em que foi elaborado um conjunto de planilhas com formato capaz de ser utilizado em diferentes Sistemas de Informação Geográfica e de interpolação de dados georreferenciados. / This thesis presents a study based on the zoning of geotechnical parameters resulting from core boring, carried out in the basaltic bedrock located in the area of the Itaipu Hydroelectric Power Plant (Foz do Iguaçu - PR). These zonings were carried out based on the interpolation of the data by means of ordinary kriging and multiquadric equations. The data provided by core boring analyzed in this research are: Rock Quality Designation (RDQ), degree of alteration, degree of consistency and degree of fracturing. The interpolation methods were evaluated for the RQD parameter, since such methods present similar mathematical characteristics; therefore, comparisons were made between interpolations resulting from ordinary kriging and multiquadric equations, demonstrating the similarity of these methods with real data. In this manner, the remaining parameters due to being categorized as categorical variables and, therefore, discrete, and presenting complexity for the execution of the variographic analysis of the data (experimental semi-variogram and modeling of the semi-variogram), were interpolated only by the method of the multiquadric equations. The validation of the interpolated data was carried out on the basis of a case study relating to the hydrogeotechnical behavior of the bedrock mass, which is monitored by standpipe piezometers. This validation showed that the methods employed to obtain the zonings and the modeling parameters chosen were adequate, since a high correlation was verified between the behavior trends obtained by the interpolations of the geotechnical parameters of the bedrock mass and the behavior revealed by the set of piezometers installed in the same site. The primordial stage of this job was the acquisition of historical data relating to the geological-geotechnical investigations in the area of Itaipu Dam. This data served as a starting point for the composition of an interactive map showing the location of the different types of investigations carried out in the rock and earthen masses. The resulting document permit a rapid and dynamic search through the geotechnical information, since it presents as its reference the plan view of the Itaipu dam itself. Each point of investigation is linked to the geotechnical profile. The investigations utilized in this map are: core boring, standard penetration test (SPT), cone penetration test (CPT) and manual pit. In this manner, the recovery of the historical information obtained by the geotechnical investigation the Itaipu Dam area resulted in data compilations in digital format, based upon which, a set of tabular forms was obtained of a type capable of being utilized in different Systems of Geographical Information and of interpolation of geo-referenced data.

<p>Denna rapport är en jämförande studie av utvalda konsolidanter som används till att stabilisera nedbrutet insektsangripet trä. Av de trägnagande skadeinsekter vi har i Sverige är det främst<em> </em>den<em> </em>strimmiga trägnagaren som är intressant i möbelsammanhang. I rapporten beskrivs den strimmiga trägnagaren, en liten skadeinsekt<strong> </strong>som kan åstadkomma stor skada om den får verka ostörd. Insekten finns utspridd i hela Europa och är ett stort problem då den angriper alla typer av träslag. Nedbrutet insektsangripet trä<strong> </strong>förlorar sin styrka och kan behöva konsolideras genom att injicera konsolidanter in i träet. Studien är tänkt att jämföra styrkan på de vanligast förkommande och använda konsolidanterna. Urval av dessa har dels gjorts genom att intervjua konservatorer i Sverige, Norge och Danmark, dels utifrån tillgänglig litteratur och forskning. I studien injiceras de utvalda konsolidanterna in i provbitar av artificiellt konstruerat insektsangripet trä som sedan utsätts för hållfasthetsprover. Provbitarna är utformade i kuber av björk, 45x45x45 mm och är borrade med 2 mm stora hål för att efterlikna angripet trä. Två olika typer av hållfasthetsprov har använts för att mäta styrkan hos de olika konsolidanterna, tryckhållfasthet tvärsfiber och skjuvhållfasthet. Resultaten av hållfasthetsproverna visar inga tydliga tecken på att de injicerade konsolidanterna gett någon direkt styrka till provbitarna. I tryckhållfasthets tvärsfiber finns en dock en tendens tillförhöjda värden. För att kunna dra någon slutsats bör ytterligare studier genomföras.</p> / <p>This report is a comparative study of a chosen set of consolidating agents used to stabilize wood suffering from the infestation of wood boring insects. When considering furniture, the most common wood boring insect in Sweden is the Furniture Beetle. This report discusses the Furniture Beetle, a small insect which if left alone, achieves a great amount of damage. This particular beetle can be found in all of Europe and is a sizable problem, since it can attack all species of wood. Infested wood is destabilized by the beetles boring a web of internal tunnels throughout, which results in a loss of strength. This wood is then commonly injected with a consolidation agent to compensate for its internal weakness. The study is made to compare the strength of the most commonly used consolidating agents. These lection of agents was determined by interviewing conservators in Sweden, Norway and Denmark, as well as from accessible literature and research. In the study the selected consolidating agents are injected into trial pieces of artificially compromised wood which are in turn exposed to strength testing in a laboratory setting. The trial pieces are squares of birch wood measuring 45x45x45mm which have several 2mm holes drilled into them lengthwise, to simulate the beetle's pathways. Two types of strength testing were carried out to test the consolidation agents and their effect. One testmeasures the strength by compression across the grain, while the other puts pressure on either side, forcing the piece to fail along the grain. The results of the testing do not distinctively show that the consolidating agents impose any significant strength to the trial pieces. There is however a tendency of increased strength shown in the cross grain compression tests. To draw any firm conclusions, additional research is required.</p>

Denna rapport är en jämförande studie av utvalda konsolidanter som används till att stabilisera nedbrutet insektsangripet trä. Av de trägnagande skadeinsekter vi har i Sverige är det främst den strimmiga trägnagaren som är intressant i möbelsammanhang. I rapporten beskrivs den strimmiga trägnagaren, en liten skadeinsekt som kan åstadkomma stor skada om den får verka ostörd. Insekten finns utspridd i hela Europa och är ett stort problem då den angriper alla typer av träslag. Nedbrutet insektsangripet trä förlorar sin styrka och kan behöva konsolideras genom att injicera konsolidanter in i träet. Studien är tänkt att jämföra styrkan på de vanligast förkommande och använda konsolidanterna. Urval av dessa har dels gjorts genom att intervjua konservatorer i Sverige, Norge och Danmark, dels utifrån tillgänglig litteratur och forskning. I studien injiceras de utvalda konsolidanterna in i provbitar av artificiellt konstruerat insektsangripet trä som sedan utsätts för hållfasthetsprover. Provbitarna är utformade i kuber av björk, 45x45x45 mm och är borrade med 2 mm stora hål för att efterlikna angripet trä. Två olika typer av hållfasthetsprov har använts för att mäta styrkan hos de olika konsolidanterna, tryckhållfasthet tvärsfiber och skjuvhållfasthet. Resultaten av hållfasthetsproverna visar inga tydliga tecken på att de injicerade konsolidanterna gett någon direkt styrka till provbitarna. I tryckhållfasthets tvärsfiber finns en dock en tendens tillförhöjda värden. För att kunna dra någon slutsats bör ytterligare studier genomföras. / This report is a comparative study of a chosen set of consolidating agents used to stabilize wood suffering from the infestation of wood boring insects. When considering furniture, the most common wood boring insect in Sweden is the Furniture Beetle. This report discusses the Furniture Beetle, a small insect which if left alone, achieves a great amount of damage. This particular beetle can be found in all of Europe and is a sizable problem, since it can attack all species of wood. Infested wood is destabilized by the beetles boring a web of internal tunnels throughout, which results in a loss of strength. This wood is then commonly injected with a consolidation agent to compensate for its internal weakness. The study is made to compare the strength of the most commonly used consolidating agents. These lection of agents was determined by interviewing conservators in Sweden, Norway and Denmark, as well as from accessible literature and research. In the study the selected consolidating agents are injected into trial pieces of artificially compromised wood which are in turn exposed to strength testing in a laboratory setting. The trial pieces are squares of birch wood measuring 45x45x45mm which have several 2mm holes drilled into them lengthwise, to simulate the beetle's pathways. Two types of strength testing were carried out to test the consolidation agents and their effect. One testmeasures the strength by compression across the grain, while the other puts pressure on either side, forcing the piece to fail along the grain. The results of the testing do not distinctively show that the consolidating agents impose any significant strength to the trial pieces. There is however a tendency of increased strength shown in the cross grain compression tests. To draw any firm conclusions, additional research is required.

With the goal to continue interplanetary exploration and search for past or existent life on Mars, software and hardware for unmanned subsurface drills are being developed. Unlike drilling on Earth, interplanetary exploration drills operate with very low available power and require on-board integrated health monitoring systems, with quick-response recovery procedures, under complete autonomous operations. As many drilling faults are not known a priori, Earth-based direction and control of an unmanned interplanetary drilling operation is not practical. Such missions also require advanced robotic systems that are more susceptible to structural and mechanical failures, which motivates a need for structural health monitoring techniques relevant to interplanetary exploration systems. Structural health monitoring (SHM) is a process of detecting damage or other types of defects in structural and mechanical systems that have the potential to adversely affect the current or future performance of these systems. Strict requirements for interplanetary drilling missions create unique research problems and challenges compared with SHM procedures and techniques developed to date. These challenges include implementing sensors and devices that do not interfere with the drilling operation, producing "real-time" diagnostics of the drilling condition, and developing an automation procedure for complete autonomous operations. Thus, the completed thesis work presents basic research leading to the dynamic analysis of rotating structures with specific application to interplanetary subsurface drill systems, and the formulation of an autonomous, real-time, dynamics-based SHM technique for drilling applications. This includes modeling and validating the structural dynamic system, with and without damage or faults, for a prototype interplanetary subsurface drill, exploring the use of Laser Doppler Velocimeter sensors for use in real-time SHM, developing signal filters to remove inherent harmonic components from the dynamic signal of rotating structures, developing an automation procedure with the associated software, and validating the SHM system through laboratory experiments and field tests. The automated dynamics-based structural health monitoring technique developed in this thesis presents advanced research accomplishments leading to real-time, autonomous SHM, and it has been validated on an operating dynamic system in laboratory and field tests. The formulated SHM and drilling operation also met or exceeded all specified requirements. Other major contributions of this thesis work include the formulation and demonstration of real-time, autonomous SHM in rotating structures using Laser Doppler Velocimeter sensors.

Thèse (D.Ing.) -- Université du Québec à Chicoutimi, 2005. / Bibliogr.: f. 240-252. Document électronique également accessible en format PDF. CaQCU

Made available in DSpace on 2016-06-02T19:31:54Z (GMT). No. of bitstreams: 1 3590.pdf: 1498556 bytes, checksum: e35a7d27b705eabeb03c860c8df85ec0 (MD5) Previous issue date: 2011-03-04 / Universidade Federal de Sao Carlos / Riparian vegetation is source of wood debris in streams so variation in vegetation type promote difference in biomass and richness of these substrates, which affect composition and abundance of insects associated with submerged wood. Aquatic Coleoptera associated with submerged wood debris is pointing out to it importance in the wood breakdown. For evaluated if the vegetation type influences community of aquatic Coleoptera associated with submerged wood debris, we collected submerged wood in eight Atlantic Rainforest streams, eight Cerrado streams and we include two Semideciduous Forest streams. We applied different statistical analysis (redundancy analyses, PERMANOVA and partitioning variation) to test if the taxonomic composition in Cerrado streams was different from Atlantic Rainforest streams and to verify what cause this possible difference, environmental variables, spatial variables or both. We found 1617 organisms distributed in 12 families and 29 genus. We found two boring genus of submerged wood debris for Neotropical region, Lutrochus and Stegoelmis, which play important role to food chain of streams, due to availability of nutrients and microhabitats at wood. The results of taxonomic composition of aquatic Coleoptera associated with submerged wood debris showed differences between Atlantic Rainforest and Cerrado streams, exhibiting that the vegetation type is important factor for the composition of this community. We argued that this is because of differences in composition and structure of vegetation, which cause differences in richness and biomass of submerged wood in streams. / A mata ripária é fonte de troncos e galhos para os córregos, de modo que variações nessa vegetação geram diferenças na biomassa e na riqueza desses substratos, interferindo na composição e abundância de insetos associados a troncos submersos. Coleoptera aquáticos associados a troncos submersos se destacam no processo de decomposição de troncos submersos, através de comportamento alimentar (raspar), que favorece a instalação de micro-organismos e consequentemente aumenta a riqueza e abundância de macroinvertebrados em troncos. Para testar se o tipo de vegetação interfere na fauna de Coleoptera aquáticos associados a troncos submersos nós coletamos este substrato em 18 córregos, oito em áreas de Cerrado, oito em áreas de Mata Atlântica e em outros dois de Floresta Estacional Semidecidual. Aplicamos diferentes análises estatísticas (análise de redundância exploratória, PERMANOVA e análise de partição de variância) para testar se a composição taxonômica dessa fauna em córregos de Cerrado difere daquela de Mata Atlântica e para verificar se essa possível diferença se deve a variáveis ambientais, variáveis espaciais ou ambas. Encontramos 1617 organismos, distribuídos em 12 famílias e 29 gêneros, com destaque para dois gêneros minadores de troncos para a região Neotropical, Lutrochus e Stegoelmis, que desempenham função importante para a cadeia trófica dos córregos, pela disponibilização de nutrientes e pela capacidade de produzir ranhuras e galerias. Constatamos diferenças na composição taxonômica de Coleoptera aquáticos associados a troncos, indicando que o tipo de vegetação é importante na composição dessa fauna, principalmente devido a diferenças na composição e na estrutura da vegetação, que refletem diferenças na riqueza e na biomassa de troncos submersos em córregos.