Prediction and validation of dynamic characteristics of a valve train system with flexible components and gyroscopic effect

Hu, Bo; Zhou, Changjiang; Wang, Hongbing; Yin, Lairong

doi:10.1016/j.mechmachtheory.2020.104222

Cited by 23 publications

(12 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Osteochondroma is a three-layer typical structure: (1) the surface layer is collagen connective tissue with scarce blood vessels, which is connected with the surrounding periosteum and is closely attached to the underlying tissue; (2) the middle layer is gray-blue transparent cartilage, that is, “cartilage cap,” which is similar to normal cartilage and often calcified; (3) the base layer is the main body of the tumor, and the bone marrow containing yellow bone marrow is connected to the affected bone. In theory, osteochondroma can occur in any bone with cartilage internalized bone, an ossified form [ 12 ].…”

Section: Discussionmentioning

confidence: 99%

“…Virchow et al proposed that a single osteochondroma is a tumor formed when the epiphyseal cartilage plate is separated and grows laterally outside the bone during development. Lithtenstein et al believe that the periosteum develops abnormally, and the displaced cartilage nest continues to grow [10][11][12][13]. Osteochondroma is a three-layer typical structure: (1) the surface layer is collagen connective tissue with scarce blood vessels, which is connected with the surrounding periosteum and is closely attached to the underlying tissue; (2) the middle layer is gray-blue transparent cartilage, that is, "cartilage cap," which is similar to normal cartilage and often calcified;…”

Section: The Etiology and Pathological Basis Of Osteochondromamentioning

confidence: 99%

“…(3) the base layer is the main body of the tumor, and the bone marrow containing yellow bone marrow is connected to the affected bone. In theory, osteochondroma can occur in any bone with cartilage internalized bone, an ossified form [12].…”

Section: The Etiology and Pathological Basis Of Osteochondromamentioning

confidence: 99%

See 2 more Smart Citations

Computed Tomographic Image Processing and Reconstruction in the Diagnosis of Rare Osteochondroma

Zhao

2021

Computational and Mathematical Methods in Medicine

View full text Add to dashboard Cite

Objective. We applied computed tomography (CT) to explore the imaging manifestations of rare parts of osteochondroma. Based on the medical images, deblurring using a convolutional neural network (CNN), and three-dimensional (3D) reconstruction of the images is performed in order to improve the image diagnosis. Methods. Twelve cases of osteochondroma in rare locations confirmed by surgical pathology or clinical long-term dynamic observation were retrospectively analyzed using medical imaging and image reconstruction. There are 7 males and 5 females, with an average age of 43 years. CT examinations were performed in all cases. Image deblurring via the GAN model is performed followed by the 3D reconstruction of the higher quality images is implemented. A retrospective study was performed on the imaging manifestations of the above cases; the imaging characteristics were summarized. Results. The imaging features are the following lesions, including 4 cases of the proximal radius, 4 cases of the scapula, 2 cases of the pelvis, and 2 cases of the proximal ribs. The cartilage caps, cortex, and sternum were typical structures of the bone surface of the studied cases. In the continuous imaging features, calcification was visible in some cases, and no significant enhancement was seen in enhanced scans; there was no obvious direction of lesion growth. The image processing techniques that we performed are useful in enhancing the quality of the medical diagnosis. Conclusions. Rare site osteochondroma has certain imaging features. In most cases, we can accurately diagnose rare site osteochondroma through these features via the image processing methods that are proposed in this paper.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: The Etiology and Pathological Basis Of Osteochondromamentioning

confidence: 99%

See 1 more Smart Citation

Computed Tomographic Image Processing and Reconstruction in the Diagnosis of Rare Osteochondroma

Zhao

2021

Computational and Mathematical Methods in Medicine

View full text Add to dashboard Cite

show abstract

“…It consists of a series of components that are prone to deformation. The dynamics and kinematics performances of these components affect engine performance indices, including output power, economy, reliability, noise and vibration [ 1 , 2 ], especially at high cam rotation speeds. Therefore, developing a dynamic model that analyses the kinematics and dynamics performances of the valve strain system accurately is important.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Analysis of Dynamic Characteristics for a Valve Train System

Yin

2021

Sensors

Self Cite

View full text Add to dashboard Cite

The valve train is one of the main sources of engine vibration, and its dynamic performance is crucial for output power and fuel consumption. The flexibilities of slender bars and beams should be emphasised in the design of valve trains to develop high-power and high-speed engines with industrial applications. A flexible dynamic model of a valve train system is proposed. In the proposed model, the components, except the cam and gear bodies, are modelled as flexible bodies with multidirectional deformations. The gyroscopic effects of the camshaft, cams and gear discs are also considered to predict dynamic responses at high speeds accurately. Gear meshing, the friction of the cam–tappet pair, the centrifugal force of the cams and valve clearance are also considered. Experiments on housing vibration and pushrod stress are conducted to validate the proposed model. Results show that the proposed model can predict the dynamic stress of the flexible components well and predict the trend shown by the housing vibration. The proposed model shows that excessive cam rotation speed and valve clearance will cause intense bounce and jump phenomena. The proposed model can be an important reference for designing engine work speed, adjusting valve clearance and improving component durability.

show abstract

“…Their findings can provide a new perspective for temperature variable selection and coefficients adjustment. In addition, more factors were taken into account in the predicted model of temperature filed, such as cooling and lubrication [23,20], thermal contact resistance (TCR) [24][25][26][27]20], heat transfer coefficient [28], dynamic effect [29,30], etc.…”

mentioning

confidence: 99%

Thermal network model and experimental validation for a motorized spindle including thermal–mechanical coupling effect

Zhou

et al. 2021

Int J Adv Manuf Technol

Self Cite

View full text Add to dashboard Cite

Thermal deformation caused by temperature rise have an influence on the dynamic performance of a motorized spindle. In turn, the change in the dynamic performance will affect the temperature rise and thermal deformation of the system. However, the latter was rarely focused on in the previous literature. Therefore, a thermal network model of motorized spindle is enhanced by considering the thermal-mechanical coupling effect. Then, an iterative method is presented to solve the coupled equations, and a temperature test rig of the motorized spindle is set up to verify the proposed model. The relative error between the predicted and experimental results at two test points decreases by 9.56% and 3.44% after considering the thermal-mechanical coupling effect. The comparison with the experimental results shows that the proposed model with thermal-mechanical coupling effect can obtain a more accurate temperature field than the previous model. Key words: Motorized spindle; Thermal network model; Thermal-mechanical coupling; Temperature field IntroductionMotorized spindle is a core functional component of computer numerical control (CNC). High transmission accuracy is implemented by the spindle system because the spindle is driven by the motor directly. However, the thermal deformation of the spindle system, caused by uneven temperature rise, reduces machining precision and reliability of a motorized spindle [1]. Temperature affects not only the execution accuracy of the mechanical system [2], but also the machining accuracy of the machine tool [3]. To compensate for the error induced by the thermal deformation, an accurate temperature field prediction model of the motorized spindle is essentially studied.The temperature rise of the spindle system usually focuses on thermal characteristics. To date, considerable efforts have been dedicated on the thermal characteristics of the spindle system. As the bases of calculation for the temperature in the spindle system, a thermal-dynamic model of bearings was established by Palmgren [4] and the frictional heat of bearings was calculated by Jones [5]. Thereafter, the thermal characteristics of the spindle system have attracted increasing attention. The temperature in the spindle system was determined through the finite difference model (FDM) by Harris [6], but the thermal deformation of the spindle system was not included in their model. Later, a thermal characteristic model with thermal deformation was developed [7]. The finite element method (FEM) was also used to predict the temperature field of the spindle system [8][9][10].Recently, motorized spindles as a core part of CNC have been concerned. A finite difference model with heat transfer mechanism of motorized spindle was proposed by Bossmanns [11], and the temperature at several locations matched the measured values. Chen et al. [12] developed a thermal error model of motorized spindle and found that spindle temperature has the characteristics of time-varying, nonlinearity, and strong dependence on rotation speed. Affected by...

show abstract

Prediction and validation of dynamic characteristics of a valve train system with flexible components and gyroscopic effect

Cited by 23 publications

References 25 publications

Computed Tomographic Image Processing and Reconstruction in the Diagnosis of Rare Osteochondroma

Computed Tomographic Image Processing and Reconstruction in the Diagnosis of Rare Osteochondroma

Theoretical and Experimental Analysis of Dynamic Characteristics for a Valve Train System

Thermal network model and experimental validation for a motorized spindle including thermal–mechanical coupling effect

Contact Info

Product

Resources

About