Elevators serve a critical function in essential facilities such as hospitals and need to remain operational during and after earthquakes. However, they are still known to malfunction during earthquakes even after several design and sensing improvements required by the current code have been incorporated. Most of the damages were experienced or caused by the rail-counterweight system. Being the heaviest component of an elevator, the counterweight induced strong dynamic effects to the guiding system sometimes even collided and damaged the passenger car. A realistic analytical model of rail-counterweight system of an elevator that includes details of the supporting system is developed in this study. The nonlinearities caused by closing of the code specified clearances play an important role in determining the dynamic behavior of the system, and are thus included in this study. Also included are the acceleration inputs from different floor of building and the effect of different location of the counterweight along the guide rail. Parametric study is carried out to investigate the effect of different parameters on the seismic responses of the rail-counterweight system. In order to improve the seismic performance of the rail-counterweight system, several protective schemes are investigated. One simple approach is to increase the damping of the system using additional discrete viscous dampers. However, there is not much space available for installing the devices, and placement parallel to the spring at the roller guide assemblies is not quite effective due to contact between the restraining plate at the roller guide assemblies and the rail that makes the roller guides ineffective. Another method is to convert the top part of the weights into a tuned mass damper. This method can reduce the maximum stress in the rail if designed properly. The effectiveness of the passive tuned mass damper can be improved further by using it in an active mode by installing an actuator between the mass damper and the counterweight frame. The numerical results that confirm the effectiveness of such an active tuned mass damper are presented. As an alternative to the fully active control scheme, a semi-active control scheme using a magnetorheological damper device between the mass damper and the frame is also studied. This control approach is found to be as effective in reducing the seismic response as a fully active scheme. Since this MR damper can be operated using a simple battery, the external power requirements for implementation of this approach are quite minimal. / Ph. D.

Cranes are often the most conspicuous machines on a construction site. This is due to their large size, in addition to the important role they have in transporting heavy payloads vertically and horizontally. There are two major families of construction cranes: tower cranes and mobile cranes. Mobile cranes that are mounted on tracks are a subgroup referred to as ``crawler cranes''. Crawler cranes are widely used on construction sites, and are a backbone of the United States construction industry, thus a detailed study of these cranes' behavior is essential. This research studies the tip-over stability of crawler cranes in heavy-lifting applications. Two major applications are discussed: crawler cranes using movable counterweights and crawler cranes in tandem lifting.

The aim of the diploma thesis was the conceptual design of a service lift driven by the rigid chain. The introduction part focuses on a general description of lifts and existing issues. The following chapters contain the created lift design, construction of important design elements and functional calculations. In the conclusion, evaluation compared with hydraulic lifts and evaluation of speed of the lift, starting and braking to exact stop are performed.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-04T17:53:19Z No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T16:21:57Z (GMT) No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) / Made available in DSpace on 2016-07-13T16:21:58Z (GMT). No. of bitstreams: 1 leonardocoelhopertence.pdf: 1941969 bytes, checksum: f7f3753c2825d1dfd1c727018b9807ec (MD5) Previous issue date: 2012-06-15 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do presente estudo foi investigar os efeitos da aplicação contrapesos no VO2, FC e PE durante a pedalada unilateral. Participaram do estudo 11 ciclistas (31 ± 8 anos, 176 ± 8 cm, 70,6 ± 10,8 Kg, 22,7 ± 2,1 Kg.m2, e 64 ± 9 ml.kg-1.min-1). Os ciclistas compareceram ao laboratório em 7 dias diferentes. No primeiro dia, foram submetidos à avaliação antropométrica, a um teste de pedalada bilateral (PB) em carga constante nas potências de 60 e 100 W e cadências de 60, 75 e 90 rpm, seguido por um teste de PB incremental. Do segundo ao sétimo dia, foram realizados os testes de pedalada unilateral (PU) com o membro inferior dominante utilizando os contrapesos de 2,5 kg ou 5,0 kg ou sem contrapeso nas potências de 60 e 100 W. O VO2, FC e PE foram medidos em todos os testes de PB e PU. Os dados foram apresentados por média ± desvio padrão. Foi utilizada ANOVA para medidas repetidas e posteriormente a plotagem de Bland-Altman para verificar a concordância entre a PU e a PB. Na potência de 60 W, a PU pode ser executada sem a necessidade de aplicação de contrapesos. Na potência de 100 W, durante a PU, tanto o contrapeso de 2,5 quanto o de 5,0 Kg equipararam o VO2 com o da PB, independentemente da cadência utilizada. Para a frequência cardíaca e percepção do esforço, o uso de contrapesos na potência de 60 W mostrou-se efetivo em reproduzir a PB. Entretanto, na potência de 100 W, a aplicação de contrapesos tanto para a frequência cardíaca quanto para a percepção do esforço, não foi um método eficaz para tornar a PU similar a PB. / The aim of this study was to investigate the effects of applying counterweight on VO2, HR and RPE during single-leg cycling. The study included 11 cyclists (31 ± 8 years, 176 ± 8 cm, 70.6 ± 10.8 kg, BMI 22.7 ± 2.1 and 64 ± 9ml.kg-1.min-1). The experimental design was divided into 7 different days. On the first day, the volunteers were submitted to anthropometric evaluation, a double-leg test of cadences in powers of 60 and 100 W and cadences of 60, 75 and 90 rpm followed by a double-leg incremental test. From the second to the seventh day, were performed single-leg tests with dominant leg using the counterweight 2.5 kg or 5kg or noncounterweight and in the 60 W and 100 W powers. The VO2, HR and RPE values were measured in all tests. The data were presented by mean ± standard deviation. We used, ANOVA for repeated measures and subsequently the Bland-Altman plot to assess the agreement between single-leg and double-leg cycling. The PU60 was not different from PB60 from the point of view of oxygen uptake. At 100 W workload, both the counterweights 2.5 Kg and 5,0 Kg matched the oxygen uptake, enabling single-leg cycling to be performed with the same metabolic cost of double-leg cycling. However, at 100 W workload, the counterweight apparatus was not effective to make similar single-leg and double-leg cycling based on HR and RPE comparisons.

The master thesis encompasses the possibilities of position evaluation and drive control with the aid of SMI work enviroment. Furthermore the thesis is directed to create a program through a designed control algorithm. The work is realised on the elevator model with electronically commuted motor. An incremental scanner is used as the position sensor. The motor control unit is set up and programmed in the SmartMotorInterface software. In the next part, measurements with altered parameters are conducted. On the basis of these measurements the influence of parameters on the positioning process and its accuracy is evaluated. At the conclusion of the work, a design of laboratory task for educational purposes is created. The laboratory task is composed in such a way, that students would become familiar with the SMI work enviroment and would be able to practicaly test the setup of incremental position sensor and motor control with the aid of entered algorithm.