ADAMS2: A SPARSE MATRIX APPROACH TO THE DYNAMIC SIMULATION OF TWO-DIMENSIONAL MECHANICAL SYSTEMS

1978 ◽  
Author(s):  
N. Orlandea ◽  
J. C. Wiley ◽  
R. Wehage
2020 ◽  
Vol 6 (2) ◽  
pp. 90-97
Author(s):  
Sagir Masanawa ◽  
Hamza Abubakar

In this paper, a hybrid intelligent system that consists of the sparse matrix approach incorporated in neural network learning model as a decision support tool for medical data classification is presented. The main objective of this research is to develop an effective intelligent system that can be used by medical practitioners to accelerate diagnosis and treatment processes. The sparse matrix approach incorporated in neural network learning algorithm for scalability, minimize higher memory storage capacity usage, enhancing implementation time and speed up the analysis of the medical data classification problem. The hybrid intelligent system aims to exploit the advantages of the constituent models and, at the same time, alleviate their limitations. The proposed intelligent classification system maximizes the intelligently classification of medical data and minimizes the number of trends inaccurately identified. To evaluate the effectiveness of the hybrid intelligent system, three benchmark medical data sets, viz., Hepatitis, SPECT Heart and Cleveland Heart from the UCI Repository of Machine Learning, are used for evaluation. A number of useful performance metrics in medical applications which include accuracy, sensitivity, specificity. The results were analyzed and compared with those from other methods published in the literature. The experimental outcomes positively demonstrate that the hybrid intelligent system was effective in undertaking medical data classification tasks.


Author(s):  
Claudio Braccesi ◽  
Filippo Cianetti ◽  
Luca Landi

The evaluation of the fatigue damage performed by using the Power Spectral Density function (PSD) of stress and strain state is proving to be extremely accurate for a family of random processes characterized by the property of being stationary. The present work’s original contribution is the definition of a methodology which extracts stress and strain PSD matrices from components modelled using a modal approach (starting from a finite element modelling and analysis) within mechanical systems modelled using multibody dynamic simulation and subject to a generic random load (i.e. multiple-input, with partially correlated inputs). This capability extends the actual stress evaluation scenario (principally characterised by the use of finite element analysis approach) to the multibody dynamic simulation environment, more powerful and useful to simulate complex mechanical systems (i.e. railway, automotive, aircraft and aerospace systems). As regards the fatigue damage evaluation, a synthesis approach to evaluate an equivalent stress state expressed in terms of the PSD function of Preumont’s “equivalent von Mises stress (EVMS)”, starting from the complete stress state representation expressed in terms of PSD stress matrix and easily usable in the consolidated spectral methods, is proposed. This approach allows and has allowed the use of the above methods such as the Dirlik formula as a damage evaluation method. An additional result is the conception and implementation of a frequency domain method for the component’s most probable state of stress, allowing quickly identification of the most stressed and damageble locations. The described methodologies were developed and embedded into commercial simulation codes and verified by using as a test case a simple reference multibody model with a simple flexible component.


2018 ◽  
Vol 41 (3) ◽  
pp. 875-882 ◽  
Author(s):  
Jian-Feng Wu ◽  
Shang-Shang He ◽  
Feng Wang ◽  
Yu Wang ◽  
Xin-Gang Zhao ◽  
...  

In the readout circuits of the two-dimensional (2-D) resistive sensor arrays, various auxiliary electrical components were used to reduce their crosstalk errors but resulted in increased circuit complexity. Readout circuits with low-complexity structures were necessary for wearable electronic applications. With only several resistors and a microcontroller, readout circuit based on resistance matrix approach (RMA) achieved low complexity but suffered from small resistance range and large measurement error caused by the output ports’ internal resistances of the microcontroller. For suppressing those negative effects, we firstly proposed an improved resistance matrix approach (IRMA) by additionally sampling the voltages on all driving row electrodes in the RMA. Then the effects of the output ports’ internal resistances and the analog-to-digital converter’s accuracy for the RMA and the IRMA were simulated respectively with NI Multisim 12. Moreover, a prototype readout circuit based on the IRMA was designed and tested in actual experiments. The experimental results demonstrated that the IRMA, though it required more sampling channels and more computations, could be used in those applications needing low complexity, small measurement error and wide resistance range.


Author(s):  
Ke Liu ◽  
Madelyn Kosednar ◽  
Tomohiro Tachi ◽  
Glaucio H. Paulino

Abstract Origami-inspired mechanical systems are mostly composed of two-dimensional elements, a feature inherited from paper folding. However, do we have to comply with this restriction on our design space? Would it be more approachable to achieve desired performance by integrating elements of different abstract dimensions? In this paper, we propose an integrated structural system consisting of both two-dimensional and one-dimensional elements. We attach elastic strings onto an origami design to modify its mechanical behavior and create new features. We show that, by introducing elastic strings to the recently proposed Morph pattern, we can obtain bistable units with programmable energy landscape. The behavior of this integrated origami-string system can be described by an elegant formulation, which can be used to explore its rich programmability.


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