Title : Calculation theories & models & methods on damage & crack in metal materials & structures
Abstract:
As is well-known, at present, those calculation formulas on damage and crack produced in materials and structures under monotonous or fatigue loading, which mathematical models are mainly obtained by means of experiments. Author is based on the genetic concepts similar in life sciences, to adopt common parameters?and material constants n b f s , , ,? ? and ' , ' , ' n f s ? ? in mechanics and engineering materials, to adopt mathematical methods, with the crack and the damage as variables, proposes a series of mathematical models (formulas). For which are: a D The threshold value of damage and the threshold size of crack; the transition value and the th D th a tr D transition size between two stages; the critical values and the critical size; the damage value tr a i D and the crack size under different loading; the strength calculation i a I ' ? ,and I ?the strength standard ] [ I I ? ?? ; also have: the evolving rate and the life prediction on damage dN da dN dD / , / N N? , and crack, which are at one stage, or two stages, or three stages, or in whole process. On the other hand, for those key parameters in calculating formulas are all give out theories explains and specific physical and geometrical definitions. In addition, also provides comprehensive curves corresponded to calculation models related material behaviors at each stage to whole process, it is as below The working importance of mentioned above consist in: σ, ” 1) These research results which are made equivalent accordance obtain calculated data from damage and crack formulas of different types; that are to have important significances for designs calculations and accident analysis for engineering structures; 2) It can reduce and shorten the long experimental cycle of fatigue, damage, and fracture crack disciplines, and it have reduce vast energy consumption of significant; 3) It can save a large amount of investment in experimental equipment, manpower, and funds; 4) It can reduce vast Carbon discharge produced from vast experiments that can contribute to global attentions; 5) It can promote the development of the discipline itself will have practical significance. Due to the universality and acceptability of genetic concepts, the above theories, mathematical models and calculation methods may be widely accepted and applied by researchers, teachers, technicians and students in materials and engineering fields.
