The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad, and to confirm a sufficient sensitivity of a nano-indentation—lo...The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad, and to confirm a sufficient sensitivity of a nano-indentation—load curve method for identifying the dependence. Topological features of a network of solidification microstructures(α phase and eutectic), formed during quench in a brazing process of aluminum alloy, influence significantly dynamic mechanical responses of resulting heterogeneous material. Nano/micro indentation depth vs load characteristics of differing phases suggest a spatially sensitive mechanical response of a re-solidified fillet in the joint zone. Hence, a spatial distribution, pattern formations and other morphological characteristics of microstructures have a direct impact on an ultimate joint integrity. Topology-induced variations of indentation—load curves was presented. A hypothesis involving microstructures’ spatial distribution vs mechanical response was formulated.展开更多
Measurement the viscoelastic properties is important for studying the developmental and pathological behavior of soft biological tissues.Magnetic resonance elastography(MRE)is a non-invasive method for in vivo measure...Measurement the viscoelastic properties is important for studying the developmental and pathological behavior of soft biological tissues.Magnetic resonance elastography(MRE)is a non-invasive method for in vivo measurement of tissue viscoelasticity.As a flexible method capable of testing small samples,indentation has been widely used for characterizing soft tissues.Using 2nd-order Prony series and dimensional analysis,we analyzed and compared the model parameters estimated from both indentation and MRE.Conversions of the model parameters estimated from the two methods were established.We found that the indention test is better at capturing the dynamic response of tissues at a frequency less than 10 Hz,while MRE is better for describing the frequency responses at a relatively higher range.The results provided helpful information for testing soft tissues using indentation and MRE.The models analyzed are also helpful for quantifying the frequency response of viscoelastic tissues.展开更多
文摘The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad, and to confirm a sufficient sensitivity of a nano-indentation—load curve method for identifying the dependence. Topological features of a network of solidification microstructures(α phase and eutectic), formed during quench in a brazing process of aluminum alloy, influence significantly dynamic mechanical responses of resulting heterogeneous material. Nano/micro indentation depth vs load characteristics of differing phases suggest a spatially sensitive mechanical response of a re-solidified fillet in the joint zone. Hence, a spatial distribution, pattern formations and other morphological characteristics of microstructures have a direct impact on an ultimate joint integrity. Topology-induced variations of indentation—load curves was presented. A hypothesis involving microstructures’ spatial distribution vs mechanical response was formulated.
基金This work was supported by the National Natural Science Foundation of China(Grant 31870941)Shanghai Science and Technology Committee(Grant 1944190700).
文摘Measurement the viscoelastic properties is important for studying the developmental and pathological behavior of soft biological tissues.Magnetic resonance elastography(MRE)is a non-invasive method for in vivo measurement of tissue viscoelasticity.As a flexible method capable of testing small samples,indentation has been widely used for characterizing soft tissues.Using 2nd-order Prony series and dimensional analysis,we analyzed and compared the model parameters estimated from both indentation and MRE.Conversions of the model parameters estimated from the two methods were established.We found that the indention test is better at capturing the dynamic response of tissues at a frequency less than 10 Hz,while MRE is better for describing the frequency responses at a relatively higher range.The results provided helpful information for testing soft tissues using indentation and MRE.The models analyzed are also helpful for quantifying the frequency response of viscoelastic tissues.
