Analysis Of Dynamic Processes Research Articles

The Modal Analysis and Modeling Study of the Spacecraft Payload Load-Bearing Floor Structure

As space industry and technology develop, the spacecraft structure systems become increasingly complex and the scales become much larger. Early in the project stage, finite element analysis is required to rapidly and accurately analyze and forecast dynamic characteristics of spacecraft. Based on this, the optimized structural design of spacecraft is then determined. Theoretical analysis done, the effect of both the type and size of shell elements and solid elements on calculation result is discussed during the dynamic analysis process. Shell elements and solid elements are respectively used for the study on load-bearing structure of spacecraft payload instrument. The purpose is, based on meeting the requirement of accuracy, to quickly conduct finite element dynamic analysis of the structure in the early payload structural design and provide a reference for the optimized design of spacecraft structure.

Research on Verification and Analysis of Micro-Gyroscope Measuring System Based on Dynamic Response

Micro-gyroscope is a typical representative of MEMS development, and relative measuring and testing may acquire some important performance parameters, which facilitate analysis and mastery of the operating characteristics further. However, accuracy and reliability of the results or data from measuring system become the key problem for almost all measuring systems. Based on results produced by micro vision measuring, principles about driving and operating of micro-gyroscope are analyzed, and the theory function between input excitation and vibration response is established. With further study on the whole process of dynamic response analysis, resonant amplitude and frequency are finally defined as two decisive factors influencing the accuracy of micro-gyroscope measuring system. Focusing on experiment design and calculation analysis of the two parameters, accuracy and reliability of the system are well verified, which presents important references for other relative measuring systems of micro-gyroscope.

Effect of Material Property in Foundation during Earthquake on the Embankment

The dynamic analysis process started after any loss of embankment with associated huge damages like cracks during the earthquake. Literature review indicated that the maximum displacement during the earthquake is conducted to the crest and interface between the embankment with water reservoir, and foundations were cased. This paper evaluated the effect of material properties of the foundation for the two conditions so the result is related at the end of construction with supplying water. Numerical analyses of models were performed by finite element with plane strain method and ANSYS13 software. Earthquake recording as Nagan with 5.02 seconds and peak ground acceleration equal to PGA=0.65 is used. Results indicated that with a comparison of horizontal and vertical displacement, shear strain and shear stress so nonisotropic behavior of embankment especially in the up to part of the structure was obvious. It is required to consider an improvement of dynamic settlement with reinforcement structure in the future.

Finite-Element Comparative Analysis of Two Kinds of Meshing Rotor

This paper mainly introduces two kinds of internal mixer rotor. The professional visco-elastic fluid software--Polyflow is used to obtain dynamic simulation analysis process of the two different types of meshing rotors. The transient flow field model’s simulation results of the two intermeshing rotors which have rotated for 180 seconds are used to analyze the performance of the two rotors. And these analyses can be theoretical references for optimal design of the rotor.

Assessing the impact of lentiviral vector integration on splicing of cellular genes at the genome-wide level

Oncogenesis induced by insertional mutagenesis with gene therapy vectors occurs mainly by activation of proto-oncogenes found at or nearby the insertion site. This activation often occurs by an enhancer-mediated mechanism or by a process of splicing capture which generates chimeric transcripts comprising portions of vector and cellular mRNAs. Although the activation of oncogenes may be reduced by the use of self-inactivating design and moderate cellular promoters, how to reduce genotoxic splicing capture events and aberrant transcript formation triggered by vector integration is still unclear. We developed a modified Linear Amplification-Mediated (LAM) PCR technique, named cDNA LAM PCR (cLAM-PCR), aimed at retrieving, from the whole transcriptome of LV-transduced cells aberrantly spliced mRNAs that contain lentiviral vector (LV) sequences fused with cellular transcripts in a high-throughput fashion. The sequences of cLAM-PCR products were obtained by 454 pyrosequencing and analyzed by dedicated high-throughput computational pipeline running in a computer cluster that use a dynamic analysis process composed by different steps based on a map-reduce parallelization model. Thus, chimeric LV-genome sequences are recognized, the nucleotide position of the fused sequence is identified (the splice site), and the remaining portion mapped on the appropriate genome assembly by BLAST. We identified several established and previously unknown splice sites within the LV backbone that participate in the aberrant splicing process with variable efficiency. Results obtained with different LV designs show that integrated LVs can perturb the processing of cellular transcripts by interacting with the cellular splicing machinery and fusing with its own splice sites to cellular splice sites both upstream and downstream the integration site. So far, 70 different fusion transcripts could be identified in total, 84% of which were fused to known splice sites of gene exons, 6% were fused to uncharacterized cryptic splice sites located in introns and the remaining 10% were fused to genomic sequences not corresponding to any annotated gene. This analysis allows identifying also several different slice sites within the LV backbone that participated to the aberrabt splicing process. Quantitative PCR on different LV portions within the LV backbone allow measuring the relative contribution to the aberrant splicing process of each splice site identified. Interestingly, the amount of transcription occurring in regions outside the expression cassette reaches the 3% of the entire transgene expression. The cLAM-PCR technique, coupled to high-throughput sequencing and the computational power of our specialized data analysis pipeline allows gaining insights into the biology of vector-mediated splicing alteration. Since this process could induce neoplastic transformation by the generation of aberrant oncogenic protein, its in-depth characterization is instrumental in the development of next-generation LV with a higher safety profile.

Dynamics Analysis and Cam Profile Optimal Design of the Valve Train in the Diesel Engine with High Specific Power

The study carries out optimal design for the cam profile of the valve train in a high-specific-power diesel engine. The dynamic analysis on the original cam reveals that the original one, which leads to adequate fullness coefficient, is designed far from the material margins. The fullness coefficient and time area value are selected as the optimization objective, and the piecewise fucntion method is utilized to optimally design the cam profile. The restrictive contidons are applied to each section on the cam. Thus the function and the optimal coeficients are obtained. Then the dynamic analysis and working process simulation on the optimal valve train are carried out, and it proves that the dynamic and intake port performaces of the optimized one are greatly impoved.

Time series behavior of average dynamic conditional correlations in European real estate securities markets

PurposeThe purpose of this paper is to investigate the time series behavior of co‐movements among 11 European real estate securities markets, with each other as well as between country‐averages, over the sample period from January 1999 to January 2010 by utilizing the asymmetric dynamic conditional correlation (ADCC) technique, long‐memory tests and multiple structural break methodology.Design/methodology/approachFirst the ADCC from the multivariate GJR‐GARCH model is used to estimate the pair‐wise conditional correlations between the 11 securitized real estate markets. Then, the 11 country‐average conditional correlation series is subject to a battery of four long‐memory tests to form an “on the balance of evidence” picture; the semi‐parametric Geweke and Porter‐Hudak procedure and Robinson test, as well as the non‐parametric Hurst‐Mandelbrot R/S and Lo's modified R/S tests. Finally, the Bai and Perron's multiple structural break methodology seeks to test whether the average conditional correlations are subject to regime switching via the detection of breaks in the co‐movements of real estate securities returns.FindingsLow to moderate conditional correlations are found for these European real estate securities market and a higher level of correlation in the aftermath of the global financial crisis. The long‐memory correlation effect is present for nine European real estate securities markets. In addition, the conditional correlations are subject to regime switching with two structural breaks in four country‐average correlation series. Across the regimes, a higher level of correlation is linked to a higher level of volatility and a lower level of return, and this happened around the global financial crisis period.Research limitations/implicationsThe findings that national real estate securities correlations exhibit time‐varying and asymmetric behavior can help investors understand how real estate securities will co‐move in different market scenarios (e.g. “crisis” and “non‐crisis” times). Moreover, the process of dynamic covariance analysis and forecasting (the ultimate objective in portfolio management) should not rely too much on short‐term autoregressive moving average models. Instead, a combination of some appropriate long‐range dependence models and regime‐switching specifications is needed.Originality/valueThis paper offers useful insights into the time series behavior of average dynamic conditional correlations in European public property markets.

A Feature-Based CAD-CAE Integrated Approach of Machine Tool and its Implementation

An analysis feature-based CAD-CAE integrated approach was proposed to solve the problems of rapidly CAE modeling for static and dynamic analysis process of machine tool. Firstly, analysis features were defined in CAD system and analysis feature library was constructed for machine tool and its structural components. Secondly, analysis feature model was constructed by attaching analysis feature to CAD model interactively. Finally, ANSYS parametric design language (APDL) file was generated automatically by mapping analysis features to APDL codes, which realized the integration of CAD system and ANSYS system. Based on application programming interface (API) of SolidWorks, a parametric CAD-CAE tool oriented to static and dynamic analysis of machine tool was developed, which realized parametric modeling and automatic analysis of machine tool and improved design efficiency and quality of machine tool.

The Simulation and Fatigue Life Prediction of a Cable Harness in an Industrial Robot

This paper presents a method to simulate the behavior of the cable harness using the absolute nodal coordinat formulation (ANCF) and to predict the fatigue life while computing the strain time history of the point of interest. Rigid body dynamics is applied for the robot system, while ANCF is used for the cable harness. The simulation is performed by using the dynamic analysis process. The material property of the cable is obtained by a test. A simplified model is prepared. With these data, the behavior of the cable is simulated and the fatigue life is predicted.

Software Specifications Mining using Transaction Mapping Algorithm

Specification mining is a dynamic analysis process aimed at automatically inferring suggested specifications of a program from its execution traces. In software development it would be preferable if all programs and software projects are developed with clear, precise and documented specifications. But due to hard deadlines and `short-time-to-market' requirement, software products often come with project oriented, incomplete and even without any documented specifications. This situation is further motivated by a phenomenon termed as software evolution. As software evolves the documented specification is often not updated. This might render the original documented specification of little use after several cycles of program evolution. The above factors have contributed to high software maintenance costs. In this paper a novel technique to efficiently mine software specifications, called TM_TraceMiner is proposed which mines software specifications from program execution traces. To address the limitations of Apriori-like methods and FP-growth methods, a mining paradigm has been proposed, which uses Transaction Mapping algorithm.

Dynamic analysis of planar geared linkage mechanisms

A general approach to the dynamic analysis of planar geared linkage mechanisms (GLMs) is presented based on their structural topological characteristics and the theory of type transformation. First, the geared linkage Assur group (GLAG) turned out to be not only a kinematical determinate system but also a force determinate system. A method of force analysis for multiple joints is proposed. A systematic method for the dynamic analysis of GLAGs is obtained through decomposing a GLAG into a series of sequential independent kinematic units, such as simple links and dyads. Then, the unity and mutual reversibility between kinematic and dynamic analysis of GLAGs are revealed. The dynamic analysis models and explicit solutions for the basic kinematic units are derived from force determination and the process of dynamic analysis of GLMs is established in an algorithmic fashion. Finally, an application program has been developed through which the complete process from kinematic analysis to dynamic analysis can be accomplished automatically for any GLM. An example is given to illustrate the process.

Fatigue life prediction of a cable harness in an industrial robot using dynamic simulation

The cable which transfers the signal and power in an industrial robot has a problem of fatigue fracture like steel components. Since the cable is very flexible compared to other components of the system, it is difficult to estimate its motion numerically. Some studies have been done on a large deformation problem, especially in a cable, and a few attempts have been made to apply the absolute nodal coordinate formulation (ANCF), which can simulate a large deformation. Only researches about the fatigue life of structural cables or comparative studies of FEM and ANCF simulations can be found. This paper presents a method to simulate the behavior of the cable harness using the ANCF and to predict the fatigue life while computing the strain time history of the point of interest. Rigid body dynamics is applied for the robot system, while ANCF is used for the cable harness. The simulation is performed by using the dynamic analysis process. The material property of the cable is obtained by a test. A simplified model is prepared. With these data, the behavior of the cable is simulated and the fatigue life is predicted.

Dynamic mechanical properties of filled styrene butadiene rubber compounds: comparison of tensile and shear data

AbstractMost rubber articles are prepared from filler‐elastomer compounds and dynamic mechanical data can give valuable insight into behavior of such systems. The aim of this study was to compare complex tensile modulus E* and complex shear modulus G* using seven types of vulcanized filled rubbers and two testing devices.Carbon black and clay filled styrene butadiene rubber (SBR) compounds were tested. The E* value was measured using a dynamic mechanical analyzer (DMA DX04T from R.M.I.) and the G* value using a rubber process analyzer (RPA 2000 from Alpha Technologies) at 1 Hz, 30°C and at small deformation amplitudes common to both devices. For characterization of tested materials absolute values of complex modulus |E*| and |G*| were used together with values of loss factor tan δ.The highest values of |E*|, |G*| and tan δ in tested carbon blacks were obtained for type N330. The highest values of |E*|, |G*| and tan δ in tested clay fillers were found for organoclay Cloisite 93A.Maximum at the dependence tan δ/amplitude, obtained in a broader shear amplitude range, was found to be smaller for carbon black filled compounds than expected and maximum at this dependence for clay filled compounds was not observed.The amplitude dependences of analogous dynamic mechanical characteristics from dynamic mechanical analysis (DMA) and rubber process analysis (RPA) measurements seem to be similar. Between the analogous dynamic mechanical characteristics from DMA and from RPA usually a linear relationship exists with high correlation coefficient.Conclusions derived from DMA and RPA testing on the same series of rubber compounds seem to be the same. Copyright © 2006 John Wiley & Sons, Ltd.

Seismic Retrofit of the Oakland City Hall, Oakland, California

The seismic repair and retrofit construction of the Oakland City Hall, originally constructed in 1914, has been completed, making it now the tallest seismically isolated building in the world. The steel frame building with masonry infill walls experienced extensive damage in the 1989 Loma Prieta earthquake, and has since been the focus of an intensive process of testing, historical evaluation, dynamic analysis, retrofit design, and construction, culminating with the installation of seismic isolation. Because there were no specific applicable code provisions to guide the analysis or strengthening of steel frame structures with fenestrated masonry infill, the design approach was based on the measured capabilities of the existing materials, and on the unreduced seismic response of the isolated superstructure. This "performance-based’ approach was used throughout the design phase. The governing criteria was life safety during a strong earthquake.