Load Force Research Articles

Metabolic Profiles of Encapsulated Chondrocytes Exposed to Short-Term Simulated Microgravity.

The mechanism by which chondrocytes respond to reduced mechanical loading environments and the subsequent risk of developing osteoarthritis remains unclear. This is of particular concern for astronauts. In space the reduced joint loading forces during prolonged microgravity (10-6g) exposure could lead to osteoarthritis (OA), compromising quality of life post-spaceflight. In this study, we encapsulated human chondrocytes in an agarose gel of similar stiffness to the pericellular matrix to mimic the cartilage microenvironment. We then exposed agarose-chondrocyte constructs to simulated microgravity (SM) for four days using a rotating wall vessel (RWV) bioreactor to better assess the cartilage health risks associated with spaceflight. Metabolites extracted from media and agarose gel constructs were analyzed on liquid chromatography-mass spectrometry. Global metabolomic profiling detected a total of 1205 metabolite features, with 497 significant metabolite features identified by ANOVA (FDR-corrected p-value < 0.05). Specific metabolic shifts detected in response to SM exposure resulted in clusters of co-regulated metabolites, with glutathione, nitrogen, histidine, vitamin B3, and aminosugars metabolism identified by variable importance in projection scores. Microgravity-induced metabolic shifts in gel constructs and media were indicative of protein synthesis, energy and nucleotide metabolism, and oxidative catabolism. Microgravity associated-metabolic shifts were consistent with our previously published early osteoarthritic metabolomic profiles in human synovial fluid, suggesting that even short-term exposure to microgravity (or other reduced mechanical loading environments) may lead to the development of OA. This work further suggests the potential to detect these metabolic perturbations in synovial fluid in vivo to ascertain osteoarthritis risk in astronauts.

Grip force control under sudden change of friction.

A task as simple as holding a cup between your fingers generates complex motor commands to finely regulate the forces applied by muscles. These fine force adjustments ensure the stability and integrity of the object by preventing it from slipping out of grip during manipulation and by reacting to perturbations. To do so, our sensorimotor system constantly monitors tactile and proprioceptive information about the force object exerts on fingertips and the friction of the surfaces to determine the optimal gripforce. While the literature describes the transient responses, humans can generate to react to perturbations in load force, it is yet to be determined if humans can also react to abrupt changes in friction while already holding an object. Only recently technology using imperceivable ultrasonic vibrations became available to modulate friction in real time to investigate thisquestion. In this study, we used an object with an integrated friction modulation device suspended in a pulley system controlling the load. With this device, we explored the rapid adaptation of the sensorimotor system to changes in friction alone and in combination with changes in load. When load force and friction changed simultaneously, the grip force response was regulated based on the grip safety requirements. Participants increased their grip force in response to decrease in friction. However, they did not adjust their grip force when the friction increased, which is expected based on our biomechanical model of friction sensingmechanisms. KEY POINTS: Simple tasks like pouring water into a glass mobilize intricate interactions between fingertip sensory inputs and motor commands to account for the weight change and friction. It has been investigated how humans react to force perturbations when holding an object, but very little is known about how frictional changes are sensed and acted upon while holding an object, for example, due to sweating or condensation. We engineered a unique experimental object that utilizes imperceivable ultrasonic vibrations to change the frictional properties of the surface in a few milliseconds. This apparatus enabled us to study how human subjects react to change of friction when gripping or holding an object. We showed that humans adjust the strength of their grasp when forces in the direction of gravity either increase or decrease; however, frictional change evokes adjustments only when friction decreases.

Систематика многоинструментных наладок на станках токарной группы

Introduction. The analysis of factory lathe-automatic operations revealed a significant variety of multi-tool setups and identified its areas of application. To develop a matrix theory of accuracy for multi-tool machining and create a unified algorithmic approach to errors modeling for all possible spatial multi-tool setups, it is necessary to consider the flexibility of the technological system in all coordinate directions. In this regard, it is required to systematize a large number of existing multi-tool setups and classify it to structure the information and improve the understanding of its application. Purpose of the work is to develop a classification of multi-tool setups on multi-carriage and multi-spindle CNC lathes, enabling the creation of both a matrix model of machining accuracy for each classification class and a unified generalized matrix model of machining accuracy for the entire classification class. The work investigates the systematics of multi-tool setups, oriented toward the development of matrix models of machining accuracy. Therefore, the classification considered in this work is aimed at identifying the characteristics of force loading and deformation of the technological system during multi-tool machining. The research methods involve identifying the parameters used for classification and the hierarchy of these parameters, which determines the levels and order of the systematics. Based on the principles of systematics of multi-tool setups used in traditional automatic lathes, an analysis of its adaptation to the capabilities of modern lathes designed for multi-tool machining is conducted. Results and discussion. As a result of the research, a formalized six-level classification of multi-tool setups is developed, which includes the following aspects: the method of workpiece mounting, the set of carriages, the types of cutting tools, the types and directions of carriage feeds, the orientation of cutting tools relative to the workpiece, and the method of tool engagement (parallel, sequential). This classification takes into account the technological capabilities for organizing multi-tool machining on modern CNC lathes. The main classes of the proposed systematics of multi-tool setups in the presented work include single-carriage single-coordinate setups, single-carriage two-coordinate setups, dual-carriage single-coordinate setups, dual-carriage two-coordinate setups, and multi-carriage setups. The proposed systematics of multi-tool setups on lathe group machines is aimed at developing machining accuracy models and can serve as a basis for developing recommendations on cutting modes for these CNC machines. The proposed classification of multi-tool setups forms the foundation of the methodological support for the CAD system of lathe-automatic operations and serves as the basis for creating next-generation CAD systems for lathe operations.

DEAR-Taguchi analysis of buckling load and shear force in AA6061-T6 friction stir spot welds

DEAR-Taguchi analysis of buckling load and shear force in AA6061-T6 friction stir spot welds

Coordinated Dispatch of Power Generation and Spinning Reserve in Power Systems with High Renewable Penetration

The spinning reserve demand in high renewable penetration power systems is increasing significantly due to the stochastic and unpredictable nature of renewable power. This paper defines the expected load not supplied ratio (ELNSR) and models uncertainty factors such as unit forced outage rates, load and wind power output prediction errors based on probability density functions. It derives a quantitative relationship between system operating reserves and the ELNSR and uses this quantitative relationship as a constraint for power generation scheduling. Based on this, a coordinated generation and reserve scheduling model for power systems with large-scale wind power is established. Case study results demonstrate that the proposed model can balance both economy and reliability, coordinate the output allocation between wind power and thermal power, and provide an optimized allocation scheme for operating reserves among thermal power units to meet corresponding reliability requirements.

A Model of Interaction of Rigid Fibers in an Orthotropic Composite Rope

The purpose of research is to construct an algorithm for calculating a stress-strain state of a multilayer orthotropic composite rope. Research methodology involves constructing and solving the interaction model of parallel reinforcing rigid fiber elements regularly placed in layers connected through an elastic material. A method for calculating a stress-strain state of a multilayer orthotropic composite rope is developed. The scientific novelty of research is in the establishment of a dependency for distribution of internal loading forces in reinforcing rigid fibers on stay rope parameters. The distribution of internal loading forces in reinforcing fibers depends on the amount and relative location of fibers in a stay rope. Along the length, the stress-strain state of a rope depends on a square root of the ratio of shear modulus of elastic matrix and tensile rigidity of fibers. The practical value of the research is in that the presented method allows determining the rope stress-strain state during the designing stage of a permanent structure. This is based on structural parameters and mechanical properties of components of a composite rope and conditions of its interaction with the structure, thereby increasing reliability and operation efficiency of the structure, in particular, the cable-stayed bridge.

Dependence of mechanical and surface properties on crystallographic orientation, twin boundaries, and temperature in CoCrFeMn0.3Ni high-entropy alloys

The CoCrFeMnNi high-entropy alloy (HEA) has been widely studied for its mechanical properties and thermal stability, yet its tribological behaviour remains under explored. In this article, we investigate the effects of temperature and twin boundary spacing on the surface nanotribological properties and subsurface damage of CoCrFeMn0.3Ni HEA through molecular dynamics simulations. Among the orientations, [001] exhibits the highest friction coefficient, indicating the greatest restriction to indenter movement. Higher temperatures reduce wear rates, showing good thermal stability, likely due to thermal softening that decreases high-stress regions and the driving force for dislocation nucleation. Monocrystalline HEA shows lower scratch resistance than twinned workpieces. The loading force correlates with twin boundary distance, with twins increasing strength but excessive twins causing softening. Material removal becomes easier in large twinned workpieces. In monocrystalline HEA, plastic deformation is dominated by partial dislocation slip. However, in twinned workpieces, there are not only partial dislocation slips but also dislocation slips parallel to the twin and twin migration. These findings have important implications for HEA design and their applications in extreme conditions.

Study on ice impact damage characteristics of turboshaft engine compressor blade considering centrifugal force

When helicopters are operating in extremely cold environments, the centrifugal load generated by the high-speed rotation of the compressor blade will accelerate the impact damage of hail on the blade, damage the blade structure and rotor system dynamics, jeopardizing the operational safety of turboshaft engines, and at present, few studies consider the centrifugal load characteristics of ice impact damage of the compressor blade. This paper derives the Ramberg-Osgood stress–strain equation for the blade material and, by analyzing the effect of centrifugal forces on blade stress, characterizes the intrinsic relationship between centrifugal force and plastic strain. Utilizing implicit/explicit sequential solutions and the finite element-smooth particle hydrodynamics coupling method (FEM-SPH) to establish a dynamic model for ice impact on turboshaft engine blades, taking into account centrifugal force. A custom experimental setup was built to simulate centrifugal force loading on TC4 titanium alloy specimens, followed by ice impact damage experiments under simulated centrifugal force using a high-speed two-stage light gas gun. These experiments served to validate the accuracy of the dynamic modeling method for ice impact damage. The effects of centrifugal force on blade damage characteristics at different impact positions were analyzed. The results indicate that the centrifugal force generated by the high-speed rotation of the blade increases the overall stress experienced by the blade, thereby intensifying the plastic damage caused by the ice impact. Blades taking centrifugal force into account exhibit the greatest damage when ice impact occurs at 83.3 % span, with the effective plastic strain being 166.2 % higher compared to that not considering centrifugal force. The conclusions of this paper provide theoretical references and data support for the strength design and impact protection of turboshaft engine compressor blades.

Emergence of biphasic versus monotonic response of actin retrograde flow and cell traction force with varying substrate rigidity.

The transmission of cytoskeletal forces to the extracellular matrix through focal adhesion complexes is essential for a multitude of biological processes, such as cell migration, cell differentiation, tissue development, and cancer progression, among others. During migration, focal adhesions arrest the actin retrograde flow towards the cell interior, allowing the cell front to move forward. Here, we address a puzzling observation of the existence of two distinct phenomena: a biphasic vs a monotonic relationship of the retrograde flow and cell traction force with substrate rigidity. In the former, maximum traction force and minimum retrograde flow velocity are observed at an intermediate optimal substrate stiffness; while in the latter, the actin retrograde flow decreases and traction force increases with increasing substrate stiffness. We propose a theoretical model for cell-matrix adhesions at the leading edge of a migrating cell, incorporating a novel approach in force loading rate sensitive binding and reinforcement of focal adhesions assembly and the subsequent force-induced slowing down of actin flow. Our model exhibits both biphasic and monotonic responses of the retrograde flow and cell traction force with increasing substrate rigidity, owing to the cell's ability to sense and adapt to the fast-growing forces. Furthermore, our analysis shows how competition between different timescales regulated by loading rate sensitivity influences the biphasic versus monotonic behavior and the emergence of optimal substrate rigidity in the biphasic scenario. We also elucidate how the viscoelastic properties of the substrate regulate these nonlinear responses and predict the loss of cell sensitivity to variation in substrate rigidity when adhesions are subjected to high forces.

Analysis of Titanium Mesh Ti6Al4V Formation Using Die Press Forming Machine for Cranioplasty

Cranioplasty is required for patients with head defects, where the deformed part of the head is replaced with Ti6Al4V titanium wire implants. The titanium wire forming process is usually done manually, which can take a long time and give results that do not match the anatomical shape of the head. Therefore, it is important to develop domestic technology that can produce titanium wire automatically. This study aims to analyze the frame and mold of the automatic wire mesh molding machine before production. The tool is made using press forming method and finite element analysis with ANSYS software. The machine frame is made of 304 stainless steel material, while the mold uses ABS material. The analysis was performed with a constant load force of 100 N, corresponding to the maximum reading on the load cell. The simulation results show the deformation, strain, and von Mises stress of the machine frame and punch model, which are still far below the plastic deformation and UTS values of the material. However, the analysis results on the Ti6Al4V titanium die and mesh exceeded the UTS of the material in the cutting edge area of the die. Nevertheless, the die model can still be used because the maximum stress point is located at the edge of the die design area, where the titanium mesh will be cut when applied to the patient's skull implant. The results of this study are expected to help medical personnel in skull implant surgery and analysis of press machine manufacturing.

Forces experienced at different levels of the musculoskeletal system during horizontal decelerations

ABSTRACT Horizontal decelerations are frequently performed during team sports and are closely linked to sports performance and injury. This study aims to provide a comprehensive description of the kinetic demands of decelerations at the whole-body, structural, and tissue-specific levels of the musculoskeletal system. Team-sports athletes performed maximal-effort horizontal decelerations whilst full-body kinematics and ground reaction forces (GRFs) were recorded. A musculoskeletal model was used to determine whole-body (GRFs), structural (ankle, knee, and hip joint moments and contact forces), and tissue (twelve lower-limb muscle forces) loads. External GRFs in this study, especially in the horizontal direction, were up to six times those experienced during accelerated or constant-speed running reported in the literature. To cope with these high external forces, large joint moments (hip immediately after touchdown; ankle and knee during mid and late stance) and contact forces (ankle, knee, hip immediately after touchdown) were observed. Furthermore, eccentric force requirements of the tibialis anterior, soleus, quadriceps, and gluteal muscles were particularly high. The presented loading patterns provide the first empirical explanations for why decelerating movements are amongst the most challenging in team sports and can help inform deceleration-specific training prescription to target horizontal deceleration performance, or fatigue and injury resistance in team-sports athletes.

Energy distribution in 1D chains of foam disks subjected to low-velocity impact at different temperatures

A series of experiments is conducted to study energy transfer in a chain of foam disks as a function of temperature. These experiments use two different densities of closed-cell Polyvinyl Chloride foams as an array. A puncture testing machine impacts the chain at a velocity of 1 m/s at five different temperatures. Piezoelectric sensors capture the output and input forces of the chain during the impact, while high-speed cameras record the disk deformations. The chain’s energy retention is computed using disk deformations and loading forces. Results indicate that high-density foam chains exhibit significantly higher force and energy retention than low-density counterparts. Notably, the foam’s stiffness decreases with rising temperature, more prominently in higher-density foam. However, the proportion of energy retained by the chains remains relatively consistent across different temperatures. Additionally, both foam types show a pattern of exponential decay in energy retention along the chain. These insights offer implications for designing and optimizing energy-absorbing foam systems, paving the way for enhanced energy mitigation in low-velocity impact applications.

The Pulvinus Is the Weak Point for Stem Lodging Resistance in Ripe Barley.

Stem lodging is a serious problem for the ripe barley crop because it can reduce grain yield and quality. Although biometrical traits (stem diameter and wall thickness) and mechanical properties (stiffness and strength of the culm) have an obvious role in determining lodging resistance, they have only a partial capability to predict lodging resistance. We, therefore, investigated how factors like stem wetting and the point of application of the bending force affect the assessment of these traits. A three-point bending test using a height gauge can provide measures of bending strength (BS), material strength (σb), modulus of elasticity (E), and stiffness (EI). Since the first two parameters are of greatest interest, a quick manual method for measuring them is proposed. We used it specifically to compare the results of tests made by loading the bending force either on the node or the internode. It was shown that the pulvinus (which forms a complex with the node) is the weak point for mechanical resistance to bending in ripe barley stems, as a drop in BS between -31% and -41% (depending on whether the stems were dry or wet) was observed when the loading force was applied on the node/pulvinus complex with respect to the internode. We also found that, overall, BS plummeted -62% with respect to dry stems when the stems were wetted. This was due to an equivalent (-62%) plunge in σb. Similar drops in BS (-64%) and σb (-68%) following wetting were measured with the height gauge. Wetting, therefore, greatly lowers the mechanical resistance of stems. Moreover, the existence of a weak point-i.e., the pulvinus-in mature barley stems is an important feature that must be considered when evaluating the lodging-related characteristics of this crop. These findings improve our understanding of the mechanical properties of barley stems and, thus, our capability to identify genotypes with better lodging resistance.

Inclusion of Muscle Forces Affects Finite Element Prediction of Compression Screw Pullout but Not Fatigue Failure in a Custom Pelvic Implant

Custom implants used for pelvic reconstruction in pelvic sarcoma surgery face a high complication rate due to mechanical failures of fixation screws. Consequently, patient-specific finite element (FE) models have been employed to analyze custom pelvic implant durability. However, muscle forces have often been omitted from FE studies of the post-operative pelvis with a custom implant, despite the lack of evidence that this omission has minimal impact on predicted bone, implant, and fixation screw stress distributions. This study investigated the influence of muscle forces on FE predictions of fixation screw pullout and fatigue failure in a custom pelvic implant. Specifically, FE analyses were conducted using a patient-specific FE model loaded with seven sets of personalized muscle and hip joint contact force loading conditions estimated using a personalized neuromusculoskeletal (NMS) model. Predictions of fixation screw pullout and fatigue failure—quantified by simulated screw axial forces and von Mises stresses, respectively—were compared between analyses with and without personalized muscle forces. The study found that muscle forces had a considerable influence on predicted screw pullout but not fatigue failure. However, it remains unclear whether including or excluding muscle forces would yield more conservative predictions of screw failures. Furthermore, while the effect of muscle forces on predicted screw failures was location-dependent for cortical screws, no clear location dependency was observed for cancellous screws. These findings support the combined use of patient-specific FE and NMS models, including loading from muscle forces, when predicting screw pullout but not fatigue failure in custom pelvic implants.

External Validation of Accelerometry-Based Mechanical Loading Prediction Equations

Accurately predicting physical activity-associated mechanical loading is crucial for developing and monitoring exercise interventions that improve bone health. While accelerometer-based prediction equations offer a promising solution, their external validity across different populations and activity contexts remains unclear. This study aimed to validate existing mechanical loading prediction equations by applying them to a sample and testing conditions distinct from the original validation studies. A convenience sample of 49 adults performed walking, running, and jumping activities on a force plate while wearing accelerometers at their hip, lower back, and ankle. Peak ground reaction force (pGRF) and peak loading rate (pLR) predictions were assessed for accuracy. Substantial variability in prediction accuracy was found, with pLR showing the highest errors. These findings highlight the need to improve prediction models to account for individual biomechanical differences, sensor placement, and high-impact activities. Such refinements are essential for ensuring the models’ reliability in real-world applications, particularly in clinical and biomechanical research contexts, where accurate assessments of mechanical loading are critical for designing rehabilitation programs, injury prevention strategies, and optimizing bone health interventions.

Perencanaan Fondasi Pada Pembangunan Gedung 5 Lantai Rumah Sakit Puri Asih Salatiga

A foundation is a part of a system of substructures that holds its own weight and the entire force load of the superstructure, then passes it on to the soil and rock layers located underneath. Foundation Planning must be done carefully to obtain the appropriate carrying capacity to support the load of the structure on it. Good Foundation Planning will avoid the collapse of the structure on top of it. Before planning the foundation, it is good to carry out a soil investigation to determine the type of foundation used, in addition to the results of the soil investigation can determine the treatment of the soil so that the carrying capacity can support the construction to be built. In the research on foundation planning for this five-storey building structure, it is known that the carrying capacity value generated from sondir data with a qc value of 150 kg/cm2 calculated using the Mayerhoff method is 28198.26 kN/m2. With a combination of serving loads, the bore pile foundation is planned with a diameter of 0.5 meters and a depth of 4 meters. For reinforcement design, a combination of ultimate loads is used. From the results of the calculation of the main reinforcement used 12 D19 and the spiral reinforcement used Ø10.

Stress Distribution in Traumatized Teeth Splinted With Fiber Localizing on Incisal/Cervical Positions: A Three-Dimensional Finite Element Analysis.

The fiber splint represents an advanced treatment for traumatized dental injuries. The complete understanding of the localization of a splint on traumatized teeth remains elusive. The aim of this study was to assess the impact of the incisal/cervical positions of the fiber splint on the stress distribution of traumatized dental roots in various occlusal relationships. Three-dimensional finite element models were generated based on a cone beam computer tomogram of a patient. The incisal and cervical splints were simulated by strips that were bonded close to the incisal/cervical labial surface of traumatic teeth. Force was loaded on the incisal ridge, incisal and cervical positions on the palatal surface of each tooth to simulate the conditions of traumatized teeth during mastication. The equivalent stress (von Mises) on the traumatic teeth and abutment teeth was calculated by Ansys software (version 2021, R1). The incisal splint effectively transferred the stress from the traumatized tooth roots to the abutment teeth when force was loaded on the incisal ridge and incisal and cervical positions on the palatal surface. Nevertheless, the reduction effect was notably diminished when the cervical splint was used. Notably, in cases of cervical splints, with a loading force on the incisal ridge, there is an increase in stress on the roots of traumatized teeth, which poses a disadvantage in the management of traumatic dental injuries. The incisal splint demonstrated a more effective transfer of stress from the roots of the traumatic teeth to the abutment teeth than the cervical splint and the raw.

Anchorage and Stability of Orthodontic Mini Implants in Relation to Length and Types of Implants.

Anchorage control is crucial for achieving optimal results in orthodontic treatment. Scientific literature has documented the exploration of various methods to prevent anchorage loss, including the use of extraoral and intraoral devices. The advent of mini implants and micro implants has introduced new possibilities by allowing placement in previously inaccessible areas. These implants, also known as Temporary Anchorage Devices (TADs), significantly reduce the effort required to maintain anchorage. They are a reliable anchorage for orthodontic treatments because of their small size, ease of insertion and removal, and immediate force loading upon placement. For individuals who are uncooperative or who have periodontal disease and alveolar bone loss, mini implants provide a stable substitute for anchorage during orthodontic therapy. Studies emphasize the importance of implant length and type in determining stability and success rates. Longer implants tend to increase stability, and self-drilling designs generally offer superior anchorage compared to self-tapping variants. Furthermore, titanium implants demonstrate higher success rates than stainless steel implants, highlighting their suitability for orthodontic applications.

Atomic-scale material removal and deformation mechanism in nanoscratching GaN

Gallium nitride (GaN) is an important third-generation semiconductor material. However, due to its high hardness, high brittleness and anisotropy, the material removal efficiency of GaN during ultraprecision machining is low, and subsurface damage easily occurs. In order to achieve high-efficiency and low-damage ultra-precision machining, the model of double nanoscratches is innovatively utilized to investigate the mechanical behavioral of GaN at the atomic scale. Specifically, double nanoscratches experiments and corresponding molecular dynamics (MD) simulations were carried out on GaN (0001) crystal plane along the [101¯0] and [12¯10] crystal directions to reveal the material removal, deformation and subsurface damage mechanisms of GaN under anisotropic conditions. The results show that the plastic removal of GaN can be realized by setting loading force and scratch spacing. Scratching along the [12¯10] crystal direction has a greater ductile-brittle transition load force than the [101¯0] crystal direction. MD analysis shows that the downward-extending prismatic slip produced by scratching along the [101¯0] crystal direction is the cause of crack extension to the subsurface during the experiment. As the load force increases, the surface cracks of the double scratches expand and intersect, inducing streak-like brittle fracture. The significant increase in the lateral force of the second scratch is the main reason for the brittle fracture in the double scratch experiment. After the double nanoscratches experiment, the damage presented on the GaN subsurface mainly includes atomic scale damage such as amorphization, stacked laminations, polycrystalline nanoscratch, and phase transition. The Stacking fault bands around the damage zone inhibit the damage extension. The second scratch generates a large number of dislocations in the overlap zone and attenuates the subsurface amorphization under the influence of dislocation strengthening effect.

Micromechanisms of Medical Mg–Zn alloys during Semi-solid powder forming (SPF)

Mg alloys with advantages of biocompatibility and biodegradability are considered as a new type of medical material with great potential. Compared with casting and additive manufacturing, Semi-solid powder forming (SPF) is a promising new technique to prepare medical Mg alloys due to the characteristics of fine microstructures, a short process cycle and good comprehensive properties. In this study, the micromechanism of Mg–6Zn mixed powder materials under a semi-solid isothermal and deformation station was analyzed and discussed based on the results of SEM, EDS, XRD, synchrotron radiation X-ray computed tomography (SRXCT) and kinetic analysis. The results show all the Zn powders melt and Mg powder dissolves into the liquid Zn to form a Zn–Mg liquid wrapping around the Mg powders the semi-solid isothermal state. The powder particle boundary blurred and transgranular liquation cracking (TLC) occurs under the loading force, making the powders being broken into fragments which spheroidize and coarsen afterward. Simultaneously, the dynamic model of Mg–6Zn mixed powders was deduced and established, which agrees well with the experimental results and can predict the actual liquid fraction during SPF. The pores reconstructed by SRXCT has a low connectivity, near-spherical morphology and flat surface, combined with encapsulated microstructure with finer grains and fewer secondary phases, which are beneficial to slow down the degradation rate. Finally, the micromechanism of SPF was concluded as atomic diffusion, liquid flowing and filling, transgranular liquation cracking (TLC) of particles as well as coarsening and spheroidizing of its fragments, which provides theoretical guidance for optimizing the forming process.