Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Abstract

In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type material as the representative of the cardiac muscle in dynamic tests is introduced. The motivation of this study is to introduce a replacement material of the heart muscle to use in experimental studies of the leadless pacemaker. A particular test setup is developed to capture the experimental data based on the stress relaxation test method where its outputs are time histories of the force and displacement. The standard linear solid model is used for mathematical modeling of the heart muscle sample and a gel-type material specimen namely α-gel. Five tests with different strain history [Formula: see text] are performed by regarding and disregarding the influence of the initial ramp of the loading. The mechanical parameters of the standard linear solid model were identified with precise curve fitting. Consideration of the initial ramp significantly influences the consequences and they are so close to their experimental counterparts. The identified parameters of the standard linear solid model by regarding the influence of the initial ramp for the gel-type material are within an acceptable range for the viscoelastic properties of the calf heart tissue. These results show that the gel-type material has the potential to represent the cardiac muscle in the leadless pacemaker experimental studies. Dynamic mechanical analysis is used to characterize the dynamic viscoelastic properties for the gel by utilizing the identified parameters with taking into account the initial ramp in the frequency domain. Results show that Storage modulus, Loss modulus, and Loss tangent are strongly frequency-dependent especially at low-frequency around the heartbeat frequency range (0–2 Hz).

Investigating the influence of the viscoelastic material as a heart muscle simulator on the powering leadless pacemaker from heartbeats by using a piezoelectric beam

“…More explanations can be found in the currently published work from these authors. 26,32 The utilized test setup consisted of a test rig (refers to Figure 3), a stress relaxation test machine, a data logger, and a personal computer system.…”

“…More explanations can be found in the currently published work from these authors. 26,32 The utilized test setup consisted of a test rig (refers to Figure 3), a stress relaxation test machine, a data logger, and a personal computer system. Specific compression displacements were applied by the test machine via the upper movable holder to the samples and maintained constant after applying these initial displacements, and the resulting forces versus time were measured by the load cell.…”

“…Since the dead heart muscle properties change over time, hence, Siami et al 26 introduced a gel-type material that can represent the heart muscle in the dynamic tests. They identified the parameters of discrete elements of the SLS model for a calf heart muscle and GC-5 gel-type material.…”

“…Based on the proposed configuration, the mathematical modeling of the energy harvesting system is developed using the generalized Hamilton’s principle. The identified parameters by the authors in the previous work 26 for the GC-5 viscoelastic material are used for SLS components in the developed model. To study the effect of the dynamic behavior of the heart muscle on magnifying or decreasing the harvested energy, transmissibility analyses is carried out on the energy harvesting system attached on the cardiac muscle representative material.…”

Constitutive Equations for Analyzing Stress Relaxation and Creep of Viscoelastic Materials Based on Standard Linear Solid Model Derived with Finite Loading Rate

“…Nevertheless, the standard linear solid model is still one of the most common and popular viscoelastic models because of its simplicity and high applicability. The standard linear solid model has been widely applied to analyze the viscoelastic behaviors of a great variety of materials, including polymers [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ], single cells [ 61 , 62 , 63 , 64 , 65 ], blood vessels [ 66 , 67 ], heart muscles [ 68 ], cartilages [ 69 , 70 ], intervertebral discs [ 71 , 72 ], hydrogels [ 55 , 73 , 74 , 75 ], and various biomaterials, to name a few.…”