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Influence of Process Parameters and Sr Addition on the Microstructure and Casting Defects of LPDC A356 Alloy for Engine Blocks 被引量:10
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作者 Giulio Timelli Daniele Caliari Jovid Rakhmonov 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第6期515-523,共9页
The effects of Sr addition and pressure increase on the microstructure and casting defects of a low-pressure die cast (LPDC) AISi7Mg0.3 alloy have been studied. Metallographic and image analysis techniques have been... The effects of Sr addition and pressure increase on the microstructure and casting defects of a low-pressure die cast (LPDC) AISi7Mg0.3 alloy have been studied. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes and the amount of porosity occurring at different Sr levels and pressure parameters. The results indicate that an increase in the filling pressure induces lower heat dissipation of the liquid close to the die/core surfaces, with the formation of slightly greater dendrite arms and coarser eutectic Si particles. On the other hand, the increase in the Sr level leads to finer microstructural scale and eutectic Si. The analysed variables, within the experimental conditions, do not affect the morphology of eutectic Si particles. Higher applied pressure and Sr content generate castings with lower amount of porosiW. However, as the filling pressure increases the flow of metal inside the die cavity is more turbulent, leading to the formation of oxide films and cold shots. In the analysed range of experimental conditions, the design of experiment methodology and the analysis of variance have been used to develop statistical models that accurately predict the average size of secondary dendrite arm spacing and the amount of porosity in the low-pressure die cast AISiTMg0.3 alloy. 展开更多
关键词 Aluminium alloys engine block Microstructure Casting defects Sr addition Process parameters
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Vibration-based feature extraction of determining dynamic characteristic for engine block low vibration design 被引量:2
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作者 杜宪峰 李志军 +3 位作者 毕凤荣 张俊红 王霞 邵康 《Journal of Central South University》 SCIE EI CAS 2012年第8期2238-2246,共9页
In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition (EMD) and wavelet analysis was p... In order to maintain vibration performances within the limits of the design, a vibration-based feature extraction method for dynamic characteristic using empirical mode decomposition (EMD) and wavelet analysis was proposed. The proposed method was verified experimentally and numerically by implementing the scheme on engine block. In the implementation process, the following steps were identified to be important: 1) EMD technique in order to solve the feature extraction of vibration signals; 2) Vibration measurement for the purpose of confirming the structural weak regions of engine block in experiment; 3) Finite element modeling for the purpose of determining dynamic characteristic in time region and frequency region to affirm the comparability of response character corresponding to improvement schemes; 4) Adopting a feature index oflMF for structural improvement based on EMD and wavelet analysis. The obtained results show that IMF of signal is more sensitive to response character corresponding to improvement schemes. Finally, examination of the results confirms that the proposed vibration-based feature extraction method is very robust, and focuses on the relative merits of modification and full-scale structural optimization of engine, together with the creation of new low-vibration designs. 展开更多
关键词 feature extraction dynamic characteristic finite element model empirical mode decomposition diesel engine block
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DYNAMIC DESIGN OF INTERNAL COMBUSTION ENGINE BLOCK STRUCTURE
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作者 Yu, Ming Huang, Rongqing Lou, Yutao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1998年第1期39-43,共5页
Several main steps of internal combustion engine block structure dynamic design,such as model set up,structure dynamic response analysis,optimizing design and vibration and noise control,are discussed for the type of... Several main steps of internal combustion engine block structure dynamic design,such as model set up,structure dynamic response analysis,optimizing design and vibration and noise control,are discussed for the type of EQ6100 gasoline engine block 展开更多
关键词 engine block Dynamic design ICE
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Fatigue characteristics of sand-cast AZ91D magnesium alloy 被引量:2
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作者 Zhenming Li Alan ALuo +3 位作者 Qigui Wang Hui Zou Jichun Dai Liming Peng 《Journal of Magnesium and Alloys》 SCIE EI CAS 2017年第1期1-12,共12页
The fatigue characteristics of the AZ91D-T6 alloy samples taken from engine blocks have been investigated at 20℃ and elevated temperature(150℃).The fatigue strength and cyclic stress amplitude of the alloy significa... The fatigue characteristics of the AZ91D-T6 alloy samples taken from engine blocks have been investigated at 20℃ and elevated temperature(150℃).The fatigue strength and cyclic stress amplitude of the alloy significantly decrease with the increase of the test temperature,although cyclic hardening occurs continuously until failure for both temperatures.With the increase of the temperature,the decreased fatigue life of the alloy tested at the same stress amplitude is mainly attributed to the decreased matrix strength and the increased hysteresis energies.Fatigue failure of the engine blocks made of AZ91D-T6 alloy is mainly controlled by casting defects.For the defect-free specimens,the crack initiation behavior is determined by the single-slip(20℃)and by environment-assisted cyclic slip(150℃)during fatigue,respectively.The low-cycle fatigue lives of the alloy can be predicted using the Coffin-Manson relation and Basquin laws,the three-parameter equation and the energy-based concepts,while the high-cycle fatigue lives of the alloy fitted well with the developed long crack life model and MSF life models. 展开更多
关键词 Magnesium alloy engine blocks Fatigue properties Cyclic deformation behavior TEMPERATURE Fatigue life prediction
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Studies on Thermal Contraction of Crankshaft Bearings under Extreme Low Temperatures 被引量:4
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作者 Sever-Alexandru Haba Gheorghe Oancea 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第5期496-501,共6页
This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components h... This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components have complex geometries and to obtain the thermal contractions, in the research, used the method of finite element analysis. The phenomena of thermal contractions are studied for the cold-start situations at extreme low temperature, knowing that the cold-start phase of an internal combustion engine is the main factor that determines moving rotational and translational parts wear life. Checking the proper choice of clearance is particularly important, as the use of inappropriate values of it leads to rapid operation destruction of the engine group components. The results obtained for the thermal clearances of crankshaft bearings are mathematically modeled and the relations can be used for calculating the clearances. The mathematical models are also useful for implementing in different software tools. 展开更多
关键词 engine engine block Crankshaft bearings Thermal contraction FEA
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