Instantaneous Elastic Modulus Research Articles

A generalized Rivlin–Thomas theory for nucleation of cracks in viscoelastic materials

Recent fracture experiments using the Rivlin–Thomas pure-shear geometry in rubbery viscoelastic materials have suggested nucleation of cracks at a critical stretch, independent on loading rate. For linear material using the rate-independent cohesive model theory, the critical elongation between grips (in a quite general testing geometry) at nucleation is instead monotonically decreasing with rate of up to the square root of the ratio between the instantaneous and relaxed elastic modulus of the material. Shrimali & Lopez-Pamies have made the assumption of a constant critical stretch to develop a theory which contrasts therefore with classical models. However, we further generalize the Rivlin–Thomas theory by assuming an arbitrary relation between nucleation stretch and loading rate, which therefore includes both models as limit cases. We present a simple case of a Double Cantilever Beam (DCB) geometry with linear standard materials, to show an analytical example.

The Biomechanics of Musculoskeletal Tissues during Activities of Daily Living: Dynamic Assessment Using Quantitative Transmission-Mode Ultrasound Techniques.

The measurement of musculoskeletal tissue properties and loading patterns during physical activity is important for understanding the adaptation mechanisms of tissues such as bone, tendon, and muscle tissues, particularly with injury and repair. Although the properties and loading of these connective tissues have been quantified using direct measurement techniques, these methods are highly invasive and often prevent or interfere with normal activity patterns. Indirect biomechanical methods, such as estimates based on electromyography, ultrasound, and inverse dynamics, are used more widely but are known to yield different parameter values than direct measurements. Through a series of literature searches of electronic databases, including Pubmed, Embase, Web of Science, and IEEE Explore, this paper reviews current methods used for the in vivo measurement of human musculoskeletal tissue and describes the operating principals, application, and emerging research findings gained from the use of quantitative transmission-mode ultrasound measurement techniques to non-invasively characterize human bone, tendon, and muscle properties at rest and during activities of daily living. In contrast to standard ultrasound imaging approaches, these techniques assess the interaction between ultrasound compression waves and connective tissues to provide quantifiable parameters associated with the structure, instantaneous elastic modulus, and density of tissues. By taking advantage of the physical relationship between the axial velocity of ultrasound compression waves and the instantaneous modulus of the propagation material, these techniques can also be used to estimate the in vivo loading environment of relatively superficial soft connective tissues during sports and activities of daily living. This paper highlights key findings from clinical studies in which quantitative transmission-mode ultrasound has been used to measure the properties and loading of bone, tendon, and muscle tissue during common physical activities in healthy and pathological populations.

Brillouin spectroscopy of medically relevant samples of bovine jugular vein and pericardium

There is the rapid growth in application of Brillouin scattering spectroscopy to biomedical objects in order to characterize their mechanoelastic properties in this way. However, the possibilities and limitations of the method when applied to tissues have not yet been clarified. Here, applicability of Brillouin spectroscopy for testing the elastic response of medically relevant tissues of bovine jugular vein and pericardium was considered. Parameters of the Brillouin peak were studied for samples untreated, diepoxide-fixed, and preserved after treatment in alcohol solutions. It was found that diepoxide cross-linking resulted to a slight tendency to increase the Brillouin position for hydrated tissues. The variations in the position and width of the Brillouin peaks, associated with local fluctuations in water concentration, were reduced after diepoxide treatment in the case of the pericardium, but not in the case of the vein wall. To obtain more information about the elastic response of the protein scaffold without the participation of water, dried samples were also studied. Brillouin spectra of the dried pericardium and vein wall revealed a significant increase in the Brillouin peak position (elastic modulus) after conservation in alcohol. In the case of the vein wall, this effect was found for both collagen and elastin-related peaks, which were identified in the Brillouin spectrum. This result corresponds to a denser packing of fibrous proteins after preservation in alcohol solutions. The ability of Brillouin spectroscopy to independently characterize the effect of treatment on the instantaneous elastic modulus of various tissue components is also attractive for its application in the development of new materials for bioimplants. A comparison of the Brillouin longitudinal and Young’s elastic moduli determined for the hydrated samples of the vein and pericardium showed that there is no clear correspondence between these material parameters. The usefulness of using both experimental methods to obtain new information about the elastic response of the material is discussed.

Viscoelastic Hertzian Impact

The problem of normal impact of a rigid sphere on a Maxwell viscoelastic solid half-space is considered. The first-order asymptotic solution is constructed in the framework of Hunter’s model of viscoelastic impact. In particular, simple analytical approximations have been derived for the maximum contact force and the time to achieve it. A linear regression method is suggested for evaluating the instantaneous elastic modulus and the mean relaxation time from a set of experimental data collected for different spherical impactors and impact velocities.

Creep behavior of dry and saturated medium-grain sandstone and its relationship with conventional mechanical properties

With the large scale mining of coal and the increase of abandoned goafs under weakly cemented aquifer strata in Western China, it is urgent to study the time dependent mechanical properties of water sensitive aquifer strata. In this paper, creep behavior of dry and saturated medium-grain sandstone, which represent two limit states affected by water, were studied and compared. The results showed that water greatly weakens the compressive strength of medium-grained sandstone, but the difference in axial strain between dry and saturated rock samples decreases with the increase of confining pressure. The creep compression volume of rocks decreases with the increase of deviatoric stress, and only under low confining pressure does the creep volume of rocks exhibit expansion. There is an order of magnitude difference in creep strain between medium grained sandstone and other common rocks. The instantaneous elastic modulus has a negative exponential relationship with deviating stress. The creep rate has a positive exponential relationship with deviating stress. Based on Burges model with exponential damage variables, the law of the influence of confining pressure on creep model parameters has been discussed. The linear relationship between elastic modulus of medium-grained sandstone and parameters of Burgers model with damage was found. The research results are conducive to the convenient prediction of creep behavior of medium grained sandstone engineering and the long-term stability control of the surrounding rock.

Effect of Cyclic Loading Treatment on the Compression Energy and Creep Properties of Machine-Harvested Seed Cotton

Machine-harvested seed cotton was taken as the research object to further clarify its creep performance, minimize its power consumption during the loading process, and obtain a better loading method. The uniaxial compression creep test was carried out using the Instron universal material test bench to apply cyclic loading treatment. The test factors included cyclic loading times, cyclic stress peak, and cyclic loading frequency. The energy consumption curve of the machine-harvested seed cotton during cyclic loading was obtained through OriginPro 2019b software, and its energy change law was analyzed. Creep strain was divided into two parts, namely, initial creep strain and creep strain increment, to elucidate the creep mechanism. The Burgers model was chosen to describe the creep strain increment. Results show that machine-harvested seed cotton exhibits energy consumption hysteresis during cyclic loading. The compression energy rapidly decreases with increasing cyclic loading times and then stabilizes. Meanwhile, the compression energy increases with increasing cyclic stress peak and cyclic loading frequency. The creep strain mechanism is also the same, which first rapidly increases and then levels off. Cyclic loading times, cyclic stress peak, and cyclic loading frequency have different effects on creep strain increment, instantaneous elastic modulus, hysteresis elastic modulus, viscosity coefficient, delay time, and relative deformation index. Finally, disregarding power consumption and interaction, extending the cyclic loading time, and increasing the cyclic stress peak while simultaneously minimizing the cyclic loading frequency can reduce the relative deformation index in the creeping stage. Accordingly, the deformation retention ability in the creep is improved, but the compression energy in the cyclic loading increases. The results can provide theoretical and data support for studying the theoretical basis of the rheological properties of machine-harvested seed cotton, the design of seed cotton baling devices, and the study of bale (mold) forming quality.

Experimental and Numerical Study of Water–Rock Coupling Creep under Uniaxial Compression

In order to study the influence of the long-term strength of the rock surrounding deep roadways under the action of groundwater on surrounding rock stability, taking the rock surrounding the deep roadway of the Wanfu Coal Mine as the main research object, uniaxial compression and uniaxial creep tests were carried out on sandstone samples under different water-content states. It was found that the water content had an obvious softening effect on short-term and long-term strength, and both strengths showed a negative exponentially declining relationship. The viscosity modulus (E¯v) was put forward to describe viscoelastic creep deformation. And damage variables corresponding to E (the instantaneous elastic modulus) and E¯v were proposed. A sticky element that can describe the accelerated creep behavior was also established to improve the Nishihara model, based on the experimental results and damage theory. A comparison of the identified parameters and the experimental curves showed that the model can describe the mechanical behavior of various creep stages well. The model was developed using the ABAQUS user subroutine function, and the uniaxial compression creep experiment was simulated. The simulation results were basically consistent with the experimental results, which provide a basis for the further long-term stable use of roadway and creep failure simulation and have important practical and guiding significance.

Creep and Hardening Characteristics of Anthracite under Graded Static–Dynamic Coupled Loading

Remaining coal pillars in remining areas exhibit clear creep characteristics, and dynamic pressure accelerates their instability and failure. The creep and hardening characteristics of coal under dynamic pressure are of great engineering significance for the stability of remaining coal pillars in remining areas and their control. To investigate the creep and hardening characteristics of anthracite under static–dynamic coupled loading, graded loading creep tests with different loading rates were conducted. In this research, the creep strain, instantaneous elastic modulus, and creep rate of anthracite were studied under different graded loading rates. The results showed that the hardening effect of the samples manifested as an increasing instantaneous elastic modulus at the loading stage and a decreasing strain rate at the creep stage. When the graded loading rate increases from 0.01 to 0.1 mm/s, the instantaneous elastic modulus increases by 0.16–2.32 times. The sudden increase in the instantaneous elastic modulus at the failure stress level explains the instantaneous failure of the samples well. The actual yield levels corresponding to the peak instantaneous elastic modulus of the samples linearly decreased with increasing graded loading rate. The functional relationship between the graded loading rate and the elastic modulus hardening coefficient, the actual yield stress, and the strain rate decay coefficient were established, which could quantitatively describe the influence of different graded loading rates on the creep and hardening characteristics of anthracite and predict its creep damage.

Is decreased tissue elasticity more important than histopathological changes in ruptures of ascending aortic aneurysms?

In this study, we aimed to investigate the natural properties of ascending aortic aneurysms and to compare dilated aortic tissues of patients with ascending aortic aneurysms and the non-pathological aortic tissues of cadavers. Between January 2017 and January 2020, a total of 14 patients (12 males, 2 females; mean age: 66.6±8.4 years; range, 54 to 77 years) who underwent elective ascending aortic surgery without genetic disease or family history in the etiology were included in the study. Aortic tissues taken from the patients with ascending aortic aneurysms and cadavers without any aortic pathology were compared histopathologically and biomechanically. An experienced pathologist performed a histological evaluation with appropriate staining and scoring. In the biomechanical examination, stress-strain curves were created with the uniaxial tensile test. The instantaneous elastic modulus was calculated based on the first regions of the curves (Ei) and the slopes of the linear region close to rupturing (Es). In the pathological examination, there was no statistically significant difference in the parameters of both the patient and control groups (p>0.05). In the biomechanical examination, Ei values were significantly higher in the patients with ascending aortic aneurysms, while Es values were comparable between the groups (p=0.028 and p=0.609, respectively). Our study results showed that the tissues of the ascending aortic aneurysm were much more rigid, although no significant histopathological changes were detected. These findings are meaningful in understanding the structure of normal and pathological aortic tissue.

Gigahertz elastic modulus and OH stretching frequency correlate with Jones-Dole's B-coefficient in aqueous solutions of the Hofmeister series.

The ability of salts to change the macroscopic viscosity of their aqueous solutions is described by the Jones-Dole equation with B-coefficient for the linear concentration term. The signand value of this coefficient are often considered as a measure of the salt's structure-making/breaking ability, while the validity of this assignment is still under discussion. Here, by applying Raman and Brillouin scattering spectroscopy to various salts from the Hofmeister series, we studied a possible relation between macroscopic Jones-Dole's B-coefficient and the microscopic dynamic response. Raman spectroscopy provides information about molecular vibrations and Brillouin spectroscopy about acoustic phonons with wavelengths of hundreds of nanometers. It has been found that Jones-Dole's B-coefficient correlates linearly with the coefficients, describing the concentration dependences of the average OH stretching frequency, real and imaginary parts of gigahertz elastic modulus. These relationships have been interpreted to mean that the OH stretching frequency is a measure of the ion-induced changes in the water network that cause changes in both viscosity and gigahertz relaxation. Depolarized inelastic light scattering revealed that the addition of structure-making ions not only changes the frequency of the relaxation peak but also increases the low-frequency part of the relaxation susceptibility. It was shown that the ion-induced increase in the gigahertz elastic modulus can be described by changes in the relaxational susceptibility without a noticeable change in the instantaneous elastic modulus. The isotropic Raman contribution associated with the tetrahedral-like environment of H2O molecule does not correlate with Jones-Dole's B-coefficient, suggesting a minor influence of these tetrahedral-like configurations on viscosity.

Optimization of In Situ Indentation Protocol to Map the Mechanical Properties of Articular Cartilage.

Tissue engineering aims at developing complex composite scaffolds for articular cartilage repair. These scaffolds must exhibit a mechanical behavior similar to the whole osteochondral unit. In situ spherical indentation allows us to map the mechanical behavior of articular cartilage, avoiding removal of the underlying bone tissue. Little is known about the impact of grid spacing, indenter diameter, and induced deformation on the cartilage response to indentation. We investigated the impact of grid spacing (range: a to 3a, where a is the radius of the contact area between cartilage and indenter), indenter diameter (range: 1 to 8 mm), and deformation induced by indentation (constant indentation depth versus constant nominal deformation) on cartilage response. The bias induced by indentations performed in adjacent grid points was minimized with a 3a grid spacing. The cartilage response was indenter-dependent for diameters ranging between 1 and 6 mm with a nominal deformation of 15%. No significant differences were found using 6 mm and 8 mm indenters. Six mm and 8 mm indenters were used to map human articular cartilage with a grid spacing equal to 3a. Instantaneous elastic modulus E0 was calculated for constant indentation depth and constant nominal deformation. E0 value distribution did not change significantly by switching the two indenters, while dispersion decreased by 5–6% when a constant nominal deformation was applied. Such an approach was able to discriminate changes in tissue response due to doubling the indentation rate. The proposed procedure seems to reduce data dispersion and properly determine cartilage mechanical properties to be compared with those of complex composite scaffolds.

Investigation on internal mechanical response of asphalt mixture during creep test utilizing the Smart Aggregate

• Internal mechanical response of asphalt mixture to the creep behavior was investigated using Smart Aggregate. • Effects of particle location, stress level and temperature on the internal mechanical response were analyzed. • Relationship between internal mechanical response and creep behavior was discussed for asphalt mixture. The micro-mechanical behaviors of asphalt pavement play the essential role in its macro-mechanical properties and damage evolution. However, the efforts to research the micro-mechanical mechanism of asphalt mixture are still not enough, especially from a particle level in the laboratory. This study aims to investigate the internal mechanical response of asphalt mixture to the creep behavior with the assistance of built-in Smart Aggregate. After calibrating the force measurement for the Smart Aggregate, it was embedded in the asphalt mixture to monitor the inter-particle forces during the uniaxial static creep tests. Meanwhile, various test conditions, including particle location, stress level and temperature, were concerned to analysis their influences on the mechanical response of the Smart Aggregate. In addition, the relationships between internal mechanical responses and creep behavior were discussed. Results indicate that the applied force has a nonlinear relation to measured voltage of the Smart Aggregate, and can be obtained according to the regression model after calibration. During creep test, the Smart Aggregate performs well in acquiring the internal mechanical response of asphalt mixture. The inter-particle forces show uneven along the direction of loading stress during the creep test in asphalt mixture. The measured force increases monotonously whilst the strain increasing during creep evolution. Regarding the same temperature, there are significantly linear relations between instantaneous elastic modulus and measured force at the beginning and between eventual stiffness modulus and measured force at the end in dual logarithmic scales. Meanwhile, the slope k f of force curve in the steady shows strongly linear relation to the slope k s in equi-velocity creep stage on the Cartesian coordinates.

Micro-scale probing of the Rat's oviduct detects its viscoelastic property needed for creating a biologically relevant substrate for In-Vitro- Fertilization

Techniques used in assisted reproductive technology such as In-Vitro- Fertilization (IVF) process, often only replicate the biomechanical environment for embryo. Despite its importance, the biomechanics of the Oviduct tissue that is usually called Fallopian Tube in Human, the natural site of fertilization, has not been replicated nor sufficiently studied.This work studies the time-independent and time-dependent biomechanics of the oviduct tissue by realizing a viscoelastic model that accurately fit on the experimental indentation data collected on the mucosal epithelial lining of the oviduct tissue of rats. Nano-scale experiments with varying indentation rates ranging from 0.3 to 8 μms were conducted using atomic force microscopy (AFM) resulting in instantaneous elastic modulus ranging from 0.86 MPa to 6.46 MPa correspondingly. This result showed strong time dependency of the mechanical properties of the oviduct. An improved viscoelastic equation based on the fractional viscoelastic model was proposed. This modified relation successfully captured all the experimental data found at different rates (R2 > 0.8). Using the proposed model, the pure elasticity of the oviduct (i.e., about 317.2 kPa) and the viscoelastic parameters were found.

Paper 40: Improved Cartilage Healing with Microfracture Augmented with Fisetin & Bone Marrow Aspirate Concentrate in Acute Osteochondral Defect

Paper 40: Improved Cartilage Healing with Microfracture Augmented with Fisetin & Bone Marrow Aspirate Concentrate in Acute Osteochondral Defect

Regenerative Effect of Low-Intensity Pulsed Ultrasound and Platelet-Rich Plasma on the Joint Friction and Biomechanical Properties of Cartilage: A Non-traumatic Osteoarthritis Model in the Guinea Pig.

This study was aimed at investigating the effects of platelet-rich plasma (PRP) and low-intensity pulsed ultrasound (LIPUS) on the joint friction parameters and biomechanical properties of articular cartilage in a non-traumatic knee osteoarthritis (OA) model. Fifty adult male Dunkin Hartley guinea pigs were randomly divided into five groups: control, OA60, OA+US, OA+PRP and OA+US+PRP). Non-traumatic knee OA was induced with a single dose of 3 mg of mono-iodoacetate (MIA) by intra-articular injection. Intra-articular PRP was injected twice in the OA+PRP and OA+US+PRP groups. LIPUS was delivered in 10 sessions in the OA+US and OA+US+PRP groups. By use of the pendulum free oscillation test, joint friction (coefficient of friction) was measured. In addition, the instantaneous elastic modulus and aggregate modulus were measured using the stress-relaxation test. MIA injection decreased cartilage thickness, instantaneous elastic modulus and aggregate modulus, and increased joint friction. The friction coefficients in the OA+US and OA+US+PRP groups reached near-normal values, and there was no significant difference compared with the control group (p=0.232 and p=0.459, respectively). The instantaneous elastic modulus and aggregate modulus in the OA+US group increased significantly compared with the OA+PRP group (p < 0.05). It seems that both LIPUS and PRP injection effectively improved joint lubrication, but LIPUS was superior to PRP in improving the mechanical properties of the articular cartilage.

Creep, chloride, carbonation and sulphate attack on concrete

Deterioration of concrete structures with age and environmental factors like creep, chloride, carbonation and sulphate attack in the presence of a corrosive environment leads to a decrease in their performance in terms of load-bearing capacity and serviceability. The present work attempts to develop a model for the impairment in the strength of RC beams because of the combined effects of creep and sulphate attack. It also aims at studying the individual effects of chloride carbonation attacks with the help of established deterioration models. The equations of instantaneous elastic modulus and long term creep described in Indian standard codes (IRC 112) enable modelling the deterioration of modulus of elasticity of concrete as a function of time. The influence of sulphate attack on concrete strength against time is obtained from an empirical research study. Standard numerical models are employed to understand the effects of chloride ingress and carbonation phenomena. The consequences of the aforementioned attacks on an M30 grade concrete girder beam are presented in this paper. The results showed that the creep and sulphate attacks tend to dwindle over the course of time, while the effect of the former is more dominant than that of the latter. In addition, the initiation times for carbonation and chloride attacks were estimated, and it was observed that for a pristine RC beam chloride attack is highly imminent than carbonation.

Creep strain analysis and an improved creep model of granite based on the ratio of deviatoric stress-peak strength under different confining pressures

Creep refers to the deformation of rock with time under long-term applied stress, which occurs in most underground engineering. The creep behavior of granite in Shuangjiangkou underground powerhouse in Western Sichuan Province, China, was studied by creep tests. Based on test results, a new parameter DPR, the ratio of deviatoric stress to peak strength, is proposed. DPR is found to be a key parameter to describe creep parameters such as instantaneous elastic modulus, creep elastic modulus, and viscosity coefficient of rock under different confining pressures. Creep tests show that instantaneous elastic modulus increases with the increase of DPR. Creep elastic modulus increases when DPR changes from 0.54 to 0.7004, but decreases when DPR is from 0.7004 to 0.88, indicating fractures in rock closes first and then new fractures are generated. The viscosity coefficient of the rock increases first and then decreases with the increase of DPR, and when DPR = 0.7171, viscosity coefficient is maximum, indicating the time for the rock to reach stability is the longest in creep tests. By introducing DPR and confining pressure into the creep model, which interconnects creep parameters in a unified expression, an improved generalized Kelvin creep model is proposed which can accurately describe the primary and the secondary creep behavior of granite under given deviatoric stresses and confining pressures.

Compressive and Tensile Elastic Properties of Concrete: Empirical Factors in Span Reinforced Structures Design.

Concretes with the same strength can have various deformability that influences span structures deflection. In addition, a significant factor is the non-linear deformation of concrete dependence on the load. The main deformability parameter of concrete is the instantaneous modulus of elasticity. This research aims to evaluate the relation of concrete compressive and tensile elastic properties testing. The beam samples at 80 × 140 × 1400 cm with one rod Ø8 composite or Ø10 steel reinforcement were experimentally tested. It was shown that instantaneous elastic deformations under compression are much lower than tensile. Prolonged elastic deformations under compression are close to tensile. It results in compressive elasticity modulus exceeding the tensile. The relation between these moduli is proposed. The relation provides operative elasticity modulus testing by the bending tensile method. The elasticity modulus’s evaluation for the reinforced span structures could be based only on the bending testing results. A 10% elasticity modulus increase, which seems not significant, increases at 30–40% the stress of the reinforced span structures under load and 30% increases the cracking point stress.

Experimental Study of Compressive Mechanical Behavior of Red Sandstone after Heating-Cooling Treatment

Investigation of compressive mechanical property of rock materials after heating-cooling treatment is of great significance for deep geothermal energy exploitation. This study conducted a series of uniaxial compressive experiments on red sandstone subjected to different heating-cooling treatments, i.e., heating temperature 25, 200, 400, 600, 800, and 1000°C and cooling temperature of 10°C. The experimental results showed that with an increase in the heating temperature, the peak strength of red sandstone after heating-cooling treatments attained a maximum value under the heating temperature of 400°C. Furthermore, the variations of instantaneous elastic modulus of treated samples are the same as that of primary wave velocity. To futher reveal the failure characteristics of heating-cooling treated red sandstone, related scanning electron microscopy tests were also carried out to analyze the microstructure of red sandstone samples after various heating-cooling treatments, to provide a valuable reference for studying the mechanical properties of rock materials after heating-cooling treatments.

Effect of the improved protein-mineral additive on structural-mechanical characteristics of minced meat

The results of research on the effect of protein-mineral improved additive (PMIA) on the rheological parameters of minced meat, which can be used for manufacturing culinary products, including chopped semi-finished products of a high degree of readiness, are presented. It has been proven, that the additive can be used both as an ingredient, enriching calcium-digestible compounds and to improve a number of technological properties of minced meat, in particular after freezing, storage and thawing. The aim of the study was to determine the dependences of changes in the structural and mechanical characteristics of minced meat after the addition of PMIA and subsequent freezing to a temperature of –16…–18 °C and storage for 20 days.&#x0D; It has been found, that the addition of up to 7 % of PMIA leads to a marked increase in the conditionally instantaneous modulus of elasticity and highly elastic modulus in 4.4 times for minced beef and 2.7 and 4.4 times for chicken, respectively. It has been established, that the best stabilization of these indicators after freezing occurs at the content of PMIA at the level of 2…5 %. Studies of plastic viscosity and adhesion have shown that the use of up to 7 % of PMIA leads to an increase of 11…20 % and 26…64 %, respectively. After freezing, the plastic viscosity and adhesion of minced beef in the control decreased by 22.0 and 52 %, respectively, minced chicken – by 23.4 and 40.9 %. In the samples with a content of 7 % of PMIA, the decrease in plastic viscosity and adhesion is 7.2 and 4.4 % in minced beef and in chicken – 5.9 and 3.1 % respectively.&#x0D; It has been proven, that the use of PMIA in the amount of up to 7 % in the technology of minced meat production minimizes the negative destructive effect of low temperatures on the structural and mechanical characteristics of the finished product. Thus, it is expedient to use up to 7.0 % of the improved protein-mineral additive in the composition of minced meat to enrich the finished product with digestible calcium compounds and improve their structural and mechanical characteristics, in particular after freezing and storage