Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 215-224).

A real-time dynamic feedback control system is developed. An improved PID algorithm, called the integral separated piecewise PID scheme, is used in the control system. This algorithm is able to limit the contribution of the integral component in the PID calculation to avoid integral windup. In addition, it could use different PID parameters to adapt to different segments within one punch motion cycle. Hence, the error of the punch motion, either resulting from the machine assembly or from the machine dynamics, can be compensated by tuning the velocity of the servomotor. This is a unique feature of the new press that ensures its accuracy. / Based on the novel structure, the detailed design is then carried out, which includes the mechanical design, kinematics and inverse kinematics analysis, static force analysis, parametric design and the other related designs. A calibration method based on the experiment and computer simulation is proposed for the new press, which is also useful for the parallel mechanisms. Cooperated with Guangdong Metal Forming Machine Works Co. Ltd., a 250 KN prototype has been built and tested. / In order to ensure the desirable performance, dynamic control is necessary. The thesis uses two dynamic modeling methods to study the dynamics of the press. One is the kineto-static method. It is also called D'Alembert principle which rearranges Newton's second law and transfers a dynamic problem to an equivalent static problem by adding the inertial forces and inertial torques onto the system. The model can then be analyzed easily and exactly as a static system subjected to the inertial forces and torques and the external forces. The other method is the Lagrangian method which derives the dynamic model from the energy perspective. Based on the model, the dynamics of the press is studied by means of computer simulation and is validated experimentally. / In this thesis, a controllable hybrid mechanical metal forming press is developed, which is driven by a CSM with a flywheel and a servomotor. From a mechanism point of view, it is a closed-loop 2-DOF parallel planar five-bar mechanism with four resolute joints and one prismatic joint. Thanks to the usage of the servomotor, the punch motion of the new press can be controlled by tuning the velocity of the servomotor. Accordingly, desired punch motions for different stamping processes can be obtained. In other words, the new press is flexible and controllable like the servo mechanical press and the hydraulic press. Moreover, the CSM with flywheel provides the main power during the stamping operation, and hence, it is energy efficient. In addition, it is not expensive to build, as it uses only a small servomotor. / Metal forming is one of the oldest production processes and yet, is still one of the most commonly used processes today. Everyday, millions of parts are produced by metal forming ranging from battery caps to automobile body panels. Therefore, even a small improvement may add to significant corporative gain. / The thesis also describes the trajectory planning method for the press, which is based on the combination of the inverse kinematics and cubic spline interpolation. The trajectory is optimized under multiple constraints on velocity, acceleration and jerk of the servomotor. It guarantees the new press is controllable and energy efficient. / Two typical stamping processes, drawing and forging, are taken as examples for the operations of the new press. The results of the simulation and the experiment match well. Based on the simulation and experiments, it is found that the CSM provides the main power for the metal forming operations, while the servomotor is mainly responsible for overcoming the inertia forces to realize the desired punch motion. The experiments show that the new press is energy efficient, fast, controllable and inexpensive to build. It combines the advantages of both mechanical press and hydraulic press and has a good performance. It is expected the new press will have a great potential for the metal forming industry. (Abstract shortened by UMI.) / He, Kai. / "February 2008." / Adviser: Ruxu Du. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1902. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 147-149). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Mechanical Engineering. Title from title-page of electronic thesis. Bibliography: leaves 162-172.

In a world where fuel economy and crash safety is becoming an important factor in the automotive industry, the need for materials with very high strength-to-weight ratio is growing rapidly. One of the materials used for this purpose is the boron steel 22MnB5. Since the material has very high mechanical yield limit it is hard to produce parts using cold forming, which is the standard procedure for sheet metal forming. Therefore, the use of hot stamping is increasing. Hot stamping enables manufacturing of boron steel parts with good dimensional accuracy and low spring back. However, some amount of spring back is still present during the process. In this thesis, spring back of a hot formed 22MnB5 A-pillar is investigated using computer simulations in the software LS-DYNA. The main focus was to develop a process for simulating spring back in hot stamping. The work started with simulations of the forming and quenching stages of the hot stamping process, both on a full size and on a smaller section of the blank. Simultaneously as the simulations, a literature study was also conducted. The literature study was aimed at finding hints and information on how to build the simulations. Furthermore, interviews were made with experts on both LS-DYNA and hot stamping. A process for spring back evaluation was then created and written as an LS-DYNA keywordfile. In the developed spring back simulation, the part is taken out of the press right after the quenching is finished and placed in a space where it can cool and move freely. The simulation is conducted until the part reaches room temperature. After the quenching is done, data containing temperatures, stresses and strains of the part is exported. This data is then included in the spring back simulation where the part is cooled to room temperature. During the cooling, the stresses, strains and temperatures are equalized until the spring back reaches a steady state. The results indicate that the developed method for spring back evaluation can be used to foresee shape deviations for the intended part and process.

Ng Yiu Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 110-114). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Diagnosis concept based on thermal energy distribution --- p.6 / Chapter 1.1.1 --- A cup drawing example --- p.8 / Chapter 1.2 --- Need for 3D infrared thermal distribution measurement --- p.10 / Chapter 1.3 --- Outline of the Thesis --- p.11 / Chapter 2. --- Approach --- p.15 / Chapter 2.1 --- Similarity and extreme temperature analysis --- p.15 / Chapter 2.2 --- Thermodynamics for FEA in sheet metal stamping --- p.17 / Chapter 2.3 --- Acquisition of 3D thermal distribution --- p.20 / Chapter 3. --- Implementation of the Diagnosis System --- p.23 / Chapter 3.1 --- Thermograph acquisition --- p.23 / Chapter 3.2 --- Diagnosis system setup --- p.24 / Chapter 3.3 --- Perspective camera model --- p.25 / Chapter 3.4 --- System calibration --- p.27 / Chapter 3.4.1 --- LEDs calibration board --- p.27 / Chapter 3.4.2 --- Net-and-board calibration box --- p.29 / Chapter 3.5 --- Reconstruction algorithm --- p.33 / Chapter 3.6 --- Summary --- p.37 / Chapter 4. --- Consistency from Different Viewpoints --- p.38 / Chapter 4.1 --- Summary --- p.42 / Chapter 5. --- Visual Reconstruction of Objects --- p.44 / Chapter 5.1 --- Visual camera calibration --- p.45 / Chapter 5.2 --- Results --- p.49 / Chapter 5.2.1 --- "Cartoon model ""SiuSun""" --- p.49 / Chapter 5.2.2 --- Stamping disc --- p.51 / Chapter 5.3 --- Summary --- p.53 / Chapter 6. --- Thermal Distribution Reconstruction of Stamping Workpieces --- p.54 / Chapter 6.1 --- Infrared camera calibration --- p.54 / Chapter 6.2 --- Results --- p.57 / Chapter 6.2.1 --- Air conditioner cap --- p.57 / Chapter 6.2.2 --- Deep drawing cup --- p.59 / Chapter 6.2.3 --- Stamping cylinder from KS Factory --- p.61 / Chapter 6.3 --- Summary --- p.65 / Chapter 7. --- Infrared Camera on a Robotic Arm --- p.66 / Chapter 7.1 --- Robotic arm system setup --- p.67 / Chapter 7.2 --- System calibration --- p.68 / Chapter 7.3 --- Results --- p.77 / Chapter 7.3.1 --- Image sequence from horizontal viewpoints --- p.77 / Chapter 7.3.2 --- Image sequence from inclined viewpoints --- p.80 / Chapter 7.3.3 --- Image sequence from arbitrary viewpoints --- p.83 / Chapter 7.4 --- Comparison of the three different viewpoints --- p.85 / Chapter 7.5 --- Summary --- p.87 / Chapter 8. --- Compensation of Temperature Fade-out Problem --- p.88 / Chapter 8.1 --- Causes of temperature fade-out --- p.88 / Chapter 8.2 --- Solutions --- p.90 / Chapter 8.3 --- Summary --- p.91 / Chapter 9. --- Other Applications --- p.92 / Chapter 9.1 --- Automotive industry --- p.92 / Chapter 9.1.1 --- Background --- p.93 / Chapter 9.1.2 --- Experiment and result --- p.94 / Chapter 9.2 --- General heat transfer analysis --- p.97 / Chapter 9.3 --- Summary --- p.98 / Chapter 10. --- Conclusions --- p.99 / Chapter 10.1 --- Summary --- p.99 / Chapter 10.2 --- Future work --- p.104 / Chapter A. --- Transformation Matrices of the System --- p.106 / Bibliography --- p.110

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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Digital data distribution systems are widely used in Aerospace and Defense products to allow devices to communicate with one another. In many cases it is desirable to monitor the data traffic flowing between two points in a copper or fiber based Operational or Onboard Network System (ONS) for Flight Test Instrumentation (FTI) purposes because these ONS systems may carry important data which can be used without duplicating/installing a specific FTI data acquisition system to receive this data. The two types of network taps that can be used are Inline Network Taps and network end-point taps. This paper examines the usage of Inline Network Taps for FTI applications and how they can support network access strategies and objectives. An Inline Network Tap is a hardware device which allows access to data flowing across a network. These devices are typically active/powered and have a number of ports: a first tap port, a second tap port, and one or more mirror ports. An in-line network tap inserted between the first and second tap port passes all data traffic through unimpeded but also copies that same data to one or more mirror ports. Some Inline Network Tap devices may also pass packets when the tap is not powered or a malfunction is detected on the device via an integrated by-pass function. If the Inline Network Tap device goes offline the unit automatically bypasses the tap connection and data traffic is directed through the bypass directly to network devices. This capability is crucial for inline usage on mission critical network segments that cannot afford the risk of losing the network connection. An in-line network tap can either be based on copper or fiber technology and as a "filterable" network tap can also provide advanced packet filtering capabilities. These filterable network taps can selectively pass data, e.g., based on VLAN ID or other parameters, to a mirror port for deep analysis, monitoring and recording. Another advanced tap function that is presented in this paper is the support for inserting time stamps at the tap level in monitored packets which provides a reference time when the data content of a given packet was generated at a data source. This capability is a significant feature for FTI applications as most ONS systems do not provide time stamped data.

Hot stamping and die quenching (HS/DQ) process of AA7075 aluminum alloy is one of attractive forming techniques for producing high strength automotive structural components to encounter their poor formability at room temperature. In this technique, quenching rate of this alloy is very crucial as it affects precipitation kinetics after artificial ageing of part formed, which in turn determines the final in-service mechanical properties and corrosion performance of part. Thermal contact resistance (TCR) between two solid surfaces is the main parameter that controls heat transfer between hot AA7075 sheet and cold steel dies, and thus affects quenching rate of part formed. Therefore, the final properties of automotive parts produced by hot stamping is indirectly influenced by TCR. The common methods of determining TCR in HS/DQ are often impracticable as they require thermocouples to be inserted into complex-shaped stamping dies, punches and thin aluminum sheet (blank) to be formed. A potential mechanistic approach for determining TCR could be an attractive alternative due to its avoidance of embedded thermocouples into the tooling and blank. The mechanistic method emphasizes on physical mechanisms (roughness etc.) governing interfacial heat transfer between cold forming tools and hot blank. The proposed work focuses on utilizing the mechanistic method to predict TCR between multiple cylindrical asperities on a nominally flat (and heated) AA7075 blank surface and a rigid, flat, asperity-free (and cold) steel die surface. The asperities were considered to deform elastoplastically, increasing contact area. Subsequently, TCR correlation as a function of temperature, contact load, and contact area was formulated. To validate the mechanistic model, a series of surface asperity flattening experiments using thermocouple-embedded AA7075 blank and polished stainless steel planar dies were carried out. Good agreement between mechanistic model predictions and experimental results in term of contact area and TCR as a function of contact load were observed. / Thesis / Doctor of Philosophy (PhD)

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