scholarly journals The Influence of Wood Modification on Transfer Function of a Violin Bridge

2020 ◽  
Vol 71 (2) ◽  
pp. 163-169
Author(s):  
Miran Merhar ◽  
Miha Humar

The violin bridge is an important component of a violin since it transmits the excitation forces from the string to the violin body. Depending on its structure, at a certain frequency spectrum, the bridge acts as a damper or amplifier of excitation forces, which depends on its transfer function. In the study, transfer functions in the range from 400 Hz to 7000 Hz in vertical directions of 3 bridges were measured. The bridges were made from maple wood and supplied by different manufacturers. The bridges were then thermally modified, and the transfer functions were measured again. To determine the influence of thermal modification on material properties, a sample of maple wood was also modified together with the bridges, and the modulus of elasticity and shear modulus before and after the modification were measured. Using Ansys software, a bridge was modelled by the finite element method, by which natural frequencies and transfer functions before and after the modification were calculated. It can be confirmed from the research that wood modification influences the bridge transfer function and that the finite element method can be used to determine the dynamic properties of the bridge by knowing the wood material properties and, therefore, to predetermine the transfer function of the violin bridge before its production.

2015 ◽  
Vol 1096 ◽  
pp. 417-421
Author(s):  
Pei Luan Li ◽  
Zi Qian Huang

By the use of finite element method, this paper predicts the effects of the shapes of reinforcements with different ductility (Co) on the effective elastic response for WC-Co cemented carbide. This paper conducts a comparative study on the material properties obtained through theoretical model, numerical simulation and experimental observations. Simulation results indicate that the finite element method is more sophisticated than the theoretical prediction.


Author(s):  
Hiroshi Utsunomiya ◽  
Michael P. F. Sutcliffe ◽  
Hugh R. Shercliff ◽  
Pete S. Bate ◽  
Dan B. Miller

Roughening of the matt surface of pack rolled aluminium foil has been modelled. The model is based on the finite element method using isotropic plasticity. A distribution in material properties has been used to simulate the distribution of orientations through the material. The predictions of roughness show good quantitative agreement with the experiments.


2021 ◽  
Vol 26 (3-4) ◽  
pp. 255-264
Author(s):  
E.Y. Chugunov ◽  
◽  
A.I. Pogalov ◽  
S.P. Timoshenkov ◽  
◽  
...  

In the context of increasing the electronic components integration level, growing functionality and packaging density, as well as reducing the electronics weight and size, an integrated approach to engineering calculations of parts and assemblies of modern functionally and technically complex microelectronic products is required. Of particular importance are engineering calculations and structural modeling using computer-aided engineering systems, and also assessment of structural, technological and operational factors’ impact on the products reliability and performance. This work presents an approach to engineering calculations and microelectronic products modeling based on the finite-element method providing a comprehensive account of various factors (material properties, external loading, temperature fields, and other parameters) impact on the stress-strain state, mechanical strength, thermal condition, and other characteristics of products. On the example of parts and assemblies of products of microelectronic technology, the approximation of structures was shown and computer finite-element models were developed to study various structural and technological options of products and the effects on them. Engineering calculations and modeling of parts and assemblies were performed, taking into account the impact of material properties, design parameters and external influences on the products’ characteristics. Scientific and technical recommendations for structure optimization and design and technology solutions ensuring the products resistance to diverse effects were developed. It has been shown that an integrated approach to engineering calculations and microelectronic products modeling based on the finite-element method provides for the determination of optimal solutions taking into account structural, technological, and operational factors and allows the development of products with high tactical, technical and operational characteristics.


1999 ◽  
Vol 594 ◽  
Author(s):  
A. Wikström ◽  
P. Gudmundson ◽  
S. Suresh

AbstractIt is well known that curvature measurements may be used to obtain volume averaged stresses in thin continuous films and unpassivated lines without knowledge of the material properties of the film or lines. However, recently a method was presented which makes it possible to use curvature measurements also for the determination of volume averaged stresses in passivated lines. Since the problem is statically indeterminate the method requires knowledge of the material properties of the lines and passivation. The sensitivity of the method to uncertainties in material properties and curvature data is here investigated by utilizing the finite element method for anisotropic Cu or Al lines embedded in SiO2 passivation. Furthermore, the method is extended to cover the case of different stress-free temperatures for the lines and passivation respectively.


Author(s):  
Valeriya A. Pshenichkina ◽  
Vyacheslav V. Drozdov ◽  
Sergey I. Strok

Relevance. The study of the interaction of buildings and structures with the base during an earthquake is one of the most important tasks of the theory of earthquake resistance. The response of the structure to seismic impact depends to a large extent on the ratio of the stiffness characteristics of the soil, foundation, and foundation structure. Moreover, taking into account a rather high degree of statistical variability of the characteristics of the soil foundation, it is possible to ensure the required level of safety of a structure only through the use of probabilistic models and a quantitative assessment of the reliability of the construction-base system as a whole. At present, for the calculation of the construction - base system for seismic loads, deterministic discrete models of the finite element method are mainly used. But these models are poorly adapted for probabilistic calculations and require extensive statistical data, which are currently insufficient. Therefore, in problems of reliability assessment, it is advisable to use simplified analytical models, which make it possible to derive the value of the statistical variability of its reaction with relatively small initial information about the system. The aim of the work - based on the well-known solution for the single-mass model to present an analytical solution in the matrix form of the problem of free horizontal vibrations of a multi-mass cantilever rod on the foundation specified by the elastic half-space model. Methods. A study was made of the effect of the compliance of the soil foundation on the frequencies and forms of horizontal vibrations of the structure. A comparison of the results with the calculation performed by the finite element method is given. Results. The obtained solution is intended to conduct a probabilistic calculation of the construction-base system under seismic loads and evaluate its reliability.


2011 ◽  
Vol 71-78 ◽  
pp. 1383-1387 ◽  
Author(s):  
Wen Juan Yao ◽  
Wu Yang ◽  
Xiao Yu Liu

Taking Tianjin Yonghe bridge for example, the finite element method is adopted to simulate each stages of cable replacement process, the dates of tension, the alignment of main beam and the change of stress before and after cable replacement are compared and analysed, The measured value is greatly consistent with calculated value, Stress state of the bridge has been greatly improved, the weight of main beam bearing by the cable will be shared by a few closed cable after unloading, so the cables which are more serious corroded should be replaced.


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