Applied Mechanics and Materials Vol. 724

Abstract: The response surface method (RSM) is widely adopted for structural reliability analysis because of its numerical efficiency. However, the RSM is time consuming for large-scale applications and sometimes shows large errors in the calculation of the sensitivity of the reliability index with respect to random variables. In order to overcome these problems, this paper presents the improved method used to evaluate the failure probability of the system with multi-failure models which is based on the high dimensional model representation (HDMR) and response surface method (RSM).Once the limit state function is defined, the design point can be found by using HDMR method, through which the response surface can be established to calculate the failure probability. The series and parallel system are considered in this paper, a numerical example is presented to demonstrate the efficiency and the accuracy of the proposed method. It is shown that the efficiency of the RSM-HDMR are both high in terms of series system and parallel system.

Abstract: A modified Hamilton’s principle corresponding to initial value problems of dynamics is presented. Based on this principle and combined with Lagrange interpolation method, a symplectic method is constructed. The evaluations of the stability and accuracy of the proposed method are also given in this paper. With some numerical examples introduced, the proposed method is performing well and is a powerful tool for practical dynamic analyses.

Abstract: The calculation formula for the mechanical properties of TC4-6061 composite plate was deduced based on classical laminate theory. The stiffness, the strength, the specific stiffness and the specific strength for the plates was calculated by using the formula. The results show that with increasing of the relative thickness of titanium alloy layer, the tensile stiffness, the bending stiffness, the tensile strength and the bending strength increase rapidly, the tensile stiffness and tensile strength change little, the bending stiffness and specific bending strength first increase and then decrease.

Abstract: Segment floating is a common problem met in the construction of large-diameter crossing-river shield tunnel. The factors affecting segment floating are discussed first and analyzed by numerical simulation, including the properties of grouting material, the speed of shield tunneling, grouting pressure difference, the tunnel longitudinal stiffness, frictional force between segment rings and weight of the supporting system. The simulation results indicate that segment floating will reduce by shortening slurry’s initial solidification time, slowing shielding speed, improving the tunnel longitudinal stiffness as well as increasing the frictional force between segment rings. And some measures are given such as applying new rapid-setting slurries, shear pins, rubber mats with high friction coefficient and pre-stressed bolts

Abstract: A method based on the square difference of elemental modal strain was proposed to determine the damage location and damage degree. The square difference of elemental modal strain was expressed damage before and after. Simulation results show that: this method is effective to locate the single, multiple damages and light, severe damage with low-order modal information. Damage degrees can be initially determined by the values of the square difference of damaged-element modal strain. Furthermore, the result also shows that this method can accurately identify the damage location of plane truss structures with noise.

Abstract: The application in analytic hierarchy process and a second order moment method based on the practical simplified methods to analyze the reliability of existing structures, the reliability of each component in the floor according to the weight function is combined into the reliability of floor, floor of the minimum reliability as system reliability; Frame structure under the action of earthquake occurred shear failure as the main failure mode of structure, the shear capacity of column minus its share of the earthquake action is defined as the seismic reliability analysis of functions; Choose an engineering example illustrates the existing practical method for the seismic reliability analysis of frame structure.

Abstract: According to the previous experimental research on bond-slip, select push-out test as experimental method research on bond-slip between cold-formed thin-walled steel and foam concrete. Through the observation of the specimens in the push-out test, combining with the natural bonding mechanism and influencing factors summarized the failure mode and its law of composite member. The reference and basis for the experimental research and theoretical analysis of it in the future are provided.

Abstract: Analysis of methods of quality control, applied for binding systems and based materials was curried out. Also the classification of quality control methods for nanostructured binder (NB) in the light of its adaptability to this binder and composites on its basis is developed.The scheme of quality parameter control for NB and based materials in the framework of technological process "raw→binder→final composite" is developed. The basic characteristics of NB on the basis of quartz sands of different deposits are studied as well as the norms and requirements to controlled parameters when production process, allowing supplying quality of final product are determined.

Abstract: This paper studies on the compression properties of larch glum columns by building a finite element modeling. A three-dimension solid element SOLID 95 (Fig.1) of ANSYS is elected to simulate the test specimens firstly. The numerical simulation result (stress-strain curve) agrees with the experimental result. The highest stress value on the cross section is 12% of that along the grain, which is approximate with the result (10%) carried out from test. For the strain profile under the ultimate load, the strain distributes homogenous along the grain while the values of strain are almost the same at the corn of cross section. The modeling built in this paper can verify the compression test of the larch glum columns. It is reasonable to simplify the glum columns as transverse isotropy material.