Meso-Mechanics Analysis of Concrete: Generation of Random Aggregate Structure

2008 ◽  
Vol 400-402 ◽  
pp. 363-370
Author(s):  
Shao Fei Jiang ◽  
Zhao Qi Wu ◽  
Yun Fei Qiu
Keyword(s):  
Random Sampling ◽  
Progressive Failure ◽  
Aggregate Structure ◽  
Numerical Examples ◽  
Random Aggregate ◽  
Mechanics Analysis ◽  
Statistical Sense ◽  
Controlling Measures ◽  
External Loads ◽  
Aggregate Particles

In this paper, a new analytical method is proposed to generate concrete random aggregate structure (RAS) in meso-scopic level. This method is particular useful for the progressive failure of concrete under various external loads. In the meso-mechanics level, the concrete is taken as the composite material consisting of aggregate, mortar and interface between them. As a result, it is generated a random aggregate structure in which the shape, size and distribution of the aggregate particles resemble real concrete in the statistical sense using the Monte Carlo random sampling principle in this paper, and the method proposed can generate both regular aggregate particles and irregular ones in 2-Dimmension. It is should be noted that vector concept and some controlling measures are also proposed to avoid generating aggregate particles not consistent with real ones. Numerical examples are simulated to validate the proposed method finally.

scholarly journals The statistical aspect of fatigue of materials

1946 ◽  
Vol 187 (1011) ◽  
pp. 416-429 ◽  
Keyword(s):  
Distribution Function ◽  
External Load ◽  
Progressive Failure ◽  
Statistical Distribution ◽  
Macroscopic Scale ◽  
Fatigue Of Materials ◽  
Statistical Aspect ◽  
Statistical Sense ◽  
Statistical Distribution Function

The phenomenon, which is usually described as ‘fatigue’ of materials, but for which the term ‘progressive failure’ would be more adequate, is the expression, on a macroscopic scale, of the progressive destruction of the cohesive bonds as a result of the repetitive action of an external load. It has the typical features of a mass phenomenon; both the cohesive bonds and the load repetitions are collectives in a statistical sense (Mises 1931). By applying the fundamental rules of the theory of probability many of the experimentally established relations between the principal variables can be theoretically deduced from the purely formal assumption of the existence of a statistical distribution function of the separation-strength of cohesive bonds.

Development of a Rational Basis for Design of Advanced Brushing Tools

1994 ◽  
Vol 116 (3) ◽  
pp. 308-315 ◽  
Author(s):  
R. J. Stango ◽  
Chih-Yuan Shia ◽  
J. A. Henderson
Keyword(s):  
Service Life ◽  
Product Development ◽  
Iterative Procedure ◽  
General Framework ◽  
Analytical Procedure ◽  
Design Strategy ◽  
Rational Basis ◽  
Numerical Examples ◽  
Performance Requirements ◽  
Mechanics Analysis

In this paper, issues that are relevant to the design of brushing tool systems are examined and discussed. First, a general framework for brush design is presented that can provide a basis for the synthesis of advanced brushing tools, that is, brushes having predetermined performance characteristics and service life. The proposed general design strategy utilizes an iterative procedure that is based upon applicative considerations, performance requirements, and geometric/materials issues that are peculiar to a specific brush system. Next, an analytical procedure is developed that can facilitate the design of brush stiffness and brush compliance properties. This aspect of the design problem is formulated on the basis of nondimensional parameters that are associated with a quasi-static, large-displacement mechanics analysis for brush/workpart interaction. Numerical examples are presented illustrating the use of this approach for the design of brushing tools that possess unique stiffness/compliance functions. Implications that this design capability can have on the development of advanced brushing processes, as well as product development and brush manufacture, are briefly discussed.

Study on Dynamic Load Identification with Precision Integration Method

2011 ◽  
Vol 243-249 ◽  
pp. 184-187
Author(s):  
Ling Ling Jia ◽  
Li Bing Jin ◽  
Yang Han
Keyword(s):  
Discrete Time ◽  
Integration Method ◽  
Dynamic Loads ◽  
Load Identification ◽  
Precise Integration ◽  
Numerical Examples ◽  
Precise Integration Method ◽  
Random Loads ◽  
Ice Loads ◽  
External Loads

Based on the principle of precise integration method, for DOF and MDOF system, it is supposed that external loads are in linear regular within small discrete time. In further, a identification method of dynamic loads are proposed. And two real ice loads are used to study the new method. The results of numerical examples indicate that the precise integration method, with better steady and capability of resisting noise, are applicable for both steady or random loads. Otherwise, it can save more time for calculation and can be applied in real engineering.

scholarly journals On transmissible load formulations in topology optimization

2021 ◽  
Author(s):  
Hongjia Lu ◽  
Andrew Tyas ◽  
Matthew Gilbert ◽  
Aleksey V. Pichugin
Keyword(s):  
Topology Optimization ◽  
Analytical Solution ◽  
Load Application ◽  
Optimal Structure ◽  
Optimization Process ◽  
Numerical Examples ◽  
Cantilever Structure ◽  
External Loads ◽  
Surface Loads ◽  
Mohr’S Circle

AbstractTransmissible loads are external loads defined by their line of action, with actual points of load application chosen as part of the topology optimization process. Although for problems where the optimal structure is a funicular, transmissible loads can be viewed as surface loads, in other cases such loads are free to be applied to internal parts of the structure. There are two main transmissible load formulations described in the literature: a rigid bar (constrained displacement) formulation or, less commonly, a migrating load (equilibrium) formulation. Here, we employ a simple Mohr’s circle analysis to show that the rigid bar formulation will only produce correct structural forms in certain specific circumstances. Numerical examples are used to demonstrate (and explain) the incorrect topologies produced when the rigid bar formulation is applied in other situations. A new analytical solution is also presented for a uniformly loaded cantilever structure. Finally, we invoke duality principles to elucidate the source of the discrepancy between the two formulations, considering both discrete truss and continuum topology optimization formulations.

The Load Capacity of a Kagome Based High Authority Shape Morphing Structure

2004 ◽  
Vol 73 (1) ◽  
pp. 128-133 ◽  
Author(s):  
S. L. dos Santos e Lucato ◽  
A. G. Evans
Keyword(s):  
Load Capacity ◽  
Failure Mechanisms ◽  
Additional Constraint ◽  
Numerical Examples ◽  
Shape Morphing ◽  
Truss Core ◽  
Morphing Structure ◽  
The Individual ◽  
External Loads ◽  
Shape Changes

A protocol for optimizing a high authority shape morphing plate is described. The design incorporates an active Kagome back-plane capable of changing the shape of a solid face by transmitting loads through a tetrahedral truss core. The optimization assesses the required geometric dimensions and actuator specifications in order to maximize the permissible shape changes and load capacity. The critical external loads for all failure mechanisms of the individual components are calculated and used as constraints in the optimization. Resistance of the structure to actuation is presented as an additional constraint. The ensuing relations are subsequently used to choose the best material for a given application. Numerical examples of the procedure are given for a defined structure.

Analysis of frames with non-prismatic members

2000 ◽  
Vol 27 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Giray Ozay ◽  
Ahmet Topcu
Keyword(s):  
Stiffness Matrix ◽  
Beam Theory ◽  
Shear Deformations ◽  
Numerical Examples ◽  
Analysis Technique ◽  
Wide Range ◽  
Integration Techniques ◽  
Fixed End ◽  
External Loads ◽  
High Depth

This paper presents a more realistic and comprehensive static analysis technique for structures having non-prismatic members. In the proposed method a general stiffness matrix for non-prismatic members that is applicable to Timoshenko beam theory has been derived. The stiffness coefficients have been determined for constant, linear, and parabolic height variations of members, employing analytical and (or) numerical integration techniques. Uniform, triangular, and trapezoidal distributed loads over the entire member or along any part of it, concentrated loads, moments at points on the member, and any of these load combinations are taken into consideration to determine the fixed-end forces. A computer program has been coded in Fortran which analyses two-dimensional frames using the proposed stiffness matrix and fixed-end forces for a wide range of external loads. The fixed-end forces may include the effect of shear deformations. The importance of the shear deformations in non-prismatic members with high depth-to-span ratios is shown using numerical examples. The accuracy of the proposed analysis technique is verified by comparing the results of the numerical examples with those obtained from the general analysis program SAP90 using a large number of subelements. Key words: computer programs, fixed-end forces, loads (forces), non-prismatic (tapered), shear deformations, stiffness, structural analysis.

Sign in / Sign up

Export Citation Format

Share Document