Simulation of forced vibration in milling process considering gyroscopic moment and rotary inertia

2016 ◽  
Vol 89 (9-12) ◽  
pp. 2821-2836 ◽  
Author(s):  
Mohammad Mahdi Jalili ◽  
Jamal Hesabi ◽  
Mohammad Mahdi Abootorabi
Keyword(s):  
Forced Vibration ◽  
Milling Process ◽  
Rotary Inertia ◽  
Gyroscopic Moment

Wave-Induced Vibrations of an Axial-Loaded Immersed Timoshenko Beam Carrying an Eccentric Tip Mass with Rotary Inertia

2010 ◽  
Vol 54 (01) ◽  
pp. 15-33
Author(s):  
Jong-Shyong Wu ◽  
Chin-Tzu Chen
Keyword(s):  
Closed Form ◽  
Timoshenko Beam ◽  
Forced Vibration ◽  
Natural Frequencies ◽  
Closed Form Solution ◽  
Form Solution ◽  
Rotary Inertia ◽  
Mode Shapes ◽  
Mode Superposition Method ◽  
Tip Mass

Under the specified assumptions for the equation of motion, the closed-form solution for the natural frequencies and associated mode shapes of an immersed "Euler-Bernoulli" beam carrying an eccentric tip mass possessing rotary inertia has been reported in the existing literature. However, this is not true for the immersed "Timoshenko" beam, particularly for the case with effect of axial load considered. Furthermore, the information concerning the forced vibration analysis of the foregoing Timoshenko beam caused by wave excitations is also rare. Therefore, the first purpose of this paper is to present a technique to obtain the closed-form solution for the natural frequencies and associated mode shapes of an axial-loaded immersed "Timoshenko" beam carrying eccentric tip mass with rotary inertia by using the continuous-mass model. The second purpose is to determine the forced vibration responses of the latter resulting from excitations of regular waves by using the mode superposition method incorporated with the last closed-form solution for the natural frequencies and associated mode shapes of the beam. Because the determination of normal mode shapes of the axial-loaded immersed "Timoshenko" beam is one of the main tasks for achieving the second purpose and the existing literature concerned is scarce, the details about the derivation of orthogonality conditions are also presented. Good agreements between the results obtained from the presented technique and those obtained from the existing literature or conventional finite element method (FEM) confirm the reliability of the presented theories and the developed computer programs for this paper.

A Pole/Zero Placement Approach to Reducing Structure Vibration in End Milling

Manufacturing ◽  
2003 ◽  
Author(s):  
J.-J. Junz Wang ◽  
C. Y. Huang
Keyword(s):  
Forced Vibration ◽  
End Milling ◽  
Cutting Parameters ◽  
Milling Process ◽  
Depth Of Cut ◽  
Milling Force ◽  
Structure Dynamics ◽  
Vibration Model ◽  
Structure Vibration ◽  
The Fourier Transform

Forced vibration or the steady state vibration in a milling process inevitably occurs due to the periodic excitation of the intermittent cutting engagement of the milling cutter on the work and the structure, and it almost always exist even in the absence of chatter in a stable milling system, leading to dimensional and surface error and premature wear in tool and machine components. In this paper, an analytical model for the forced vibration in an end milling process is derived and criteria in selecting cutting conditions to reduce the forced vibration are presented. The analytic expression for the forced vibration due to the periodic milling force is obtained as the product of the Fourier transform of the milling force and the frequency transform of the structure dynamics. Analysis of the vibration model shows that the structure vibration can be reduced by selecting cutting parameters so that the zeroes of the frequency transform of the milling process function are near the poles of the structure dynamics. A design equation in terms of cutter geometry, axial depth of cut and structure natural frequency is obtained for the conditions when the forced vibration can be minimized. The presented analysis is illustrated through numerical simulation and verified by experimental results.

scholarly journals An updated Simpson-Based Method for Chatter Stability Prediction in Milling

2021 ◽  
Author(s):  
Zhenghu Yan ◽  
Changfu Zhang ◽  
Jianli Jia ◽  
Baoji Ma ◽  
Xinguang Jiang ◽  
...  
Keyword(s):  
Forced Vibration ◽  
Degrees Of Freedom ◽  
Computation Time ◽  
Milling Process ◽  
Small Time ◽  
The State ◽  
Stability Lobe ◽  
The Stability ◽  
The One ◽  
Delay Differential

Abstract An updated Simpson-based method (USBM) is presented for milling stability analysis. Firstly, the delay differential equation (DDE) is employed to describe the milling process mathematically. Then, the tooth passing period is divided into two subintervals, i.e., the free and forced vibration intervals. Only the forced vibration interval is divided into many equal small-time intervals. Subsequently, the DDE in the state space is solved based on direct integration. By combining the two-step Simpson method and the semi-discretization method, the state transition matrix of the milling system is constructed. The comparison of convergence rate is conducted to validate the accuracy of the proposed method. The results show that the proposed method converges faster than the benchmark methods. The stability lobe diagrams for the one degree of freedom (one-DOF) and two degrees of freedom (two-DOF) milling systems are also obtained by different methods for further evaluation. Meanwhile, the computation time analysis is also carried out. It is revealed that the proposed USBM has advantages in both accuracy and efficiency. Besides, the proposed method can accurately and efficiently predict the stability of milling with both large and low immersion conditions.

Study of The Pharmacological Activity and Heavy Metal Content of Eichhornia Crassipes Extract

2019 ◽  
Vol 2 (2) ◽  
pp. 91-95 ◽  
Author(s):  
Jimmy Jimmy ◽  
Diah Indriani Widiputri ◽  
Paulus Gunawan
Keyword(s):  
Heavy Metal ◽  
Pharmacological Activity ◽  
Water Hyacinth ◽  
Metal Content ◽  
Eichhornia Crassipes ◽  
High Light Intensity ◽  
Milling Process ◽  
Heavy Metal Content ◽  
Solvent Ratio ◽  
Negative Impacts

Eichhornia crassipes is well-known as water hyacinth. Water hyacinth grows rapidly in the nutrient-rich water and high light intensity places. The uncontrollable growth of water hyacinth has caused many negative impacts to the environment. For instance, interrupted water transport and decreased population of aquatic lives. The capacity of utilising water hyacinth is slower than water hyacinth growth and water hyacinth is still considered as a threat to theecosystem. This work was focused on the study of the pharmacological activity and heavy metal content of water hyacinth in Lake Cipondoh, Tangerang. Fresh water hyacinth was pre-treated through oven-drying and milling process. After that, each part of the plant was macerated by using multiple extraction method with 96% ethanol/water and three variations of sample-to-solvent ratios (1:30, 1:50, and 1:75 w/v). The result of the experiment showed thatwater hyacinth leaves produced an extract with lowest IC 50 (55.76 ± 6.73 ppm) compared toother parts. The most optimum solvent used to achieve this result was 96% ethanol/water (1:1 v/v). In order to obtain the lowest antioxidant activity, the sample to solvent ratio used was 1:50 and the heavy metal in the extract was very low. With this result, it was concluded that there is a promising opportunity to apply the water hyacinth growing in Lake Cipondoh, Tangerang as herbal medicine ingredient. Through this utilization, the overall number of water hyacinth in Indonesia can be reduced or at the least be controlled, so that the environmental problem caused by this plant can be minimized.

INCREASE OF THE ELECTRIC DRIVE LOAD UNDER ACTION OF GYROSCOPIC MOMENT

2016 ◽  
Vol 2016 (6) ◽  
pp. 44-49
Author(s):  
A. Antonov ◽  
◽  
V. Kireyev ◽  
I. Petukhov ◽  
◽  
...  
Keyword(s):  
Electric Drive ◽  
Gyroscopic Moment
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