Applied Mechanics and Materials Vols. 752-753

Abstract: The article deals with dynamic and acoustic characteristics of the temporary steel bridge structures. Their construction is usually associated with the need of temporary replacement of the permanent bridge structures which were damaged or completely destroyed due to natural disasters or by human forces during the military operations or terrorist attacks. If some area is affected such this disaster, it usually gets into the difficult economic situation and it is not possible to recover the permanent construction in real time. In many cases there arises a situation that the temporary structure performs its function for years or permanently. In view of this fact, it is necessary to solve a number of defects, especially with regard to the long-term dynamic stresses in the structure and to excessive noise, which arises due to the traffic, because this structure is not primarily designed for it.

Abstract:

As the sensing element and a driving element for vibration control using smart materials, the structural vibration control is very active field for research and application. This paper mainly study the characteristics of piezoelectric self-sensing vibration .Through the action analysis of research on Piezoelectric Actuator establish a self-sensing piezoelectric vibration damper and a model of self-sensing piezoelectric absorber . Then through the experiment and simulation, get the study on its characteristics.

Abstract: The floor impact sound is a structure-borne sound that is propagated not only to the apartment directly below but also to various other locations. This study identifies how much floor impact sound, which is perceived as a problem for the whole apartment building rather than a problem for just the upper and lower floors, is propagated to surrounding apartments. Further, this study derives various variables for the cause of noise occurring in the apartment building. The measurement results indicate that most of the energy (38–54%) is propagated to the lower floor, which is an apartment directly underneath, for the noise produced when the floor slab is excited. Furthermore, it is found that the noise is propagated simultaneously to the apartments on the upper floor, as well as to the left and right sides.

Abstract: The review of the main physical and mechanical characteristics of steel and nonmetallic composite reinforcements is presented in the article. Also there are complex studying, analysis and synthesis of available information. Much attention is paid to recommendations for designing building constructions of different functions with nonmetallic composite reinforcements. Scopes of nonmetallic composite reinforcements in the construction industry in Russia and abroad are considered.Information about main producer and the official distributor of composite reinforcements is provided in the article. This company is the official distributor in the Northwest of the Russian Federation. Their production is successfully used on many objects under construction in Russia. Materials of the article are based on the real photographic materials provided by personal archive of the company.

Abstract: The purpose of this study was to develop an environmental database for construction finish materials organized by building element as part of an effort to develop an environmental effect assessment program for buildings. To this end, a classification system has been developed for building elements that satisfies the demands from construction project stakeholders to acquire environmental information. Furthermore, among the construction materials, an environmental database of the finish materials has been developed for each building element based on reference substances and the impact indexes of six environmental effect categories of the national LCI DB.

Abstract: Composite concrete beams made of prefabricated prestressed or non-prestressed element and cast-in-place reinforced concrete slab became very popular in present-day civil engineering practice. Two concrete composite parts of beam are cast at different times. Different moduli of elasticity, consecutive load application, and differential creep and shrinkage cause unequal strains and stresses in two adjacent fibers of construction joint. The requirement is to ensure that both parts act fully compositely, because the bending and shear designs of composite members are based on this assumption. Therefore the level of shear stresses at the interface between two parts must be limited. The objective of the paper is to review the methods for the calculation of shear stresses in construction joint, and to evaluate the influence of different age of two concrete composite parts on the level of shear stresses. Calculation method alternative to Eurocode 2 method is proposed and tested. It is recommended to calculate the shear stress from difference of normal forces acting on sectional components in two neighboring sections of the element. It was observed that differential shrinkage of concrete components can significantly affect the stress distribution. Numerical studies were performed based on real-life examples of composite beams.

Abstract: In this work, study on impact damage FEM model of composite sandwich structure was performed. Sandwich structure configuration is made of carbon-epoxy face sheets and foam cores. From the finite element method analysis results of sandwich composite structure, it was confirmed that the results of analysis was reasonable. The velocity of impactor to initiate damage was estimated, and in order to investigate the damage at the predicted velocity, impact analysis using finite element method was performed. According to the impact analysis results of sandwich structure, it was confirmed that the damage was generated at the estimated impact velocity. Finally, the comparison of the numerical results with those measured by the experiment showed good agreement.

Abstract: The purpose of this paper is to study the nonlinear responses of equipment fixed on the light-weight partition wall (LWPW). The center-point flexure test (CPFT) and static load test of the light-weight partition wall (LWPW) are developed. The elastic modulus and support loading of three boards can be obtained from FPFT and static loading test. The LWPW finite element model using ANSYS is used to simulate the deformations of the board subjected to external forces. Numerical simulation results are very close to the experiment results. It demonstrates the accuracy of the ANSYS model.

Abstract: Based on the matrix calculus, the generalized second moment technique and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was presented. The transfer reliability of vibration transfer path systems with uncertain path parameters including mass and stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were obtained. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most uncertain factors can be considered to solve the random problems for vibration transfer path systems.

Abstract: Dynamic mechanical behavior of geomaterials has been widely observed in tunneling, oil and gas extraction, and blasting in civil and mining applications. It is important to understand how much energy is necessary to break or fail geomaterials to optimize the design of blasting patterns, oil and gas extractions, demolition, military defense, etc. However, there is little understanding for quantifying the required energy to break geomaterials under dynamic loading. More importantly, as typical geomaterials tend to hydrate, it is necessary to understand how much energy will be needed to break the structures under water saturation. Thus, in this study, we analyzed the consumed energy used to deform geomaterials using a split Hopkinson pressure bar (SHPB), enabling to measure stress and strain responses of geomaterials under dynamic loading condition of high strain rate (10²–10⁴/sec). Two different saturation levels (dry vs. fully saturation) in two sandstone samples having different pore sizes were tested under dynamic loading conditions. Our results demonstrate that dynamic mechanical strength (maximum stress) is greater in the dry geomaterials when compared with the saturated samples, and Young’s modulus (or maximum strain) can be a useful parameter to examine porosity effects between dry and saturated geomaterials on dynamic mechanical properties.