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Experimental research on the mechanical properties of Camellia oleifera fruit shell breaking by cutting and compression
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Haonan Zheng1, Fang Liang1, 2, *, Yanyan Zhou1, Liang Yuan1
International Journal of Agricultural and Biological Engineering | 2026, 19(3) : 307 - 313
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International Journal of Agricultural and Biological Engineering | 2026, 19(3): 307-313
• Agro-product and Food Processing Systems (AFPS) •
Experimental research on the mechanical properties of Camellia oleifera fruit shell breaking by cutting and compression
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Haonan Zheng1, Fang Liang1, 2, *, Yanyan Zhou1, Liang Yuan1
Affiliations
  • 1College of Engineering, Huazhong Agricultural University, Wuhan 430070, China
  • 2Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River, Ministry of Agriculture and Rural Affairs, Wuhan 430070, China

    • Haonan Zheng, MS candidate, research interest: agricultural mechanization engineering, Email:

    Yanyan Zhou, Undergraduate, research interest: agricultural mechanization, Email:

    Liang Yuan, Undergraduate, research interest: agricultural mechanization, Email:

About Author:

Haonan Zheng, MS candidate, research interest: agricultural mechanization engineering, Email:

Yanyan Zhou, Undergraduate, research interest: agricultural mechanization, Email:

Liang Yuan, Undergraduate, research interest: agricultural mechanization, Email:

Published: 2026-06-30 doi: 10.25165/j.ijabe.20261903.10221
Outline
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To mitigate the damage rate of Camellia oleifera seeds during the process of Camellia oleifera fruit dehulling, a Camellia oleifera fruit cutting and compression machine was developed. This machine operates on the principle that the shell-breaking stress of Camellia oleifera fruit is reduced following cutting, thereby integrating the steps of grading, cutting, compressing, and separating for the dehulling of Camellia oleifera fruit. Utilizing the electronic universal testing machine, a 4-factor single-factor test was conducted, including the number of cutting knives, cutting direction, compressing direction, and Camellia oleifera fruit size. The results showed that the average breaking force of Camellia oleifera seeds was 196.33 N. Compared with direct separating without cutting, the shell-breaking of Camellia oleifera fruit with 1, 2, 3, and 4 cuts decreased 30.14%, 38.62%, 45.05%, and 47.74%, respectively. Compared with cutting along the long axis, the shell-breaking force of Camellia oleifera fruit cutting along the minor axis decreased 8.1%; however, the effect of cutting direction on shell-breaking force is not significant. The shell-breaking force of Camellia oleifera fruit compressing along the long axis was 24.11% lower than that of Camellia oleifera fruit compressed along the minor axis. With the increase of Camellia oleifera fruit size, the shell-breaking force of Camellia oleifera fruit also increased. The shell-breaking force of 25-30 mm, 30-35 mm, and 35-40 mm was 85.62%, 127.34%, and 178.69% higher than that of 20-25 mm, respectively. In conclusion, using grading measures, making one cut along the long axis and compressing along the long axis is a suitable method for husking of Camellia oleifera fruit.

Camellia oleifera fruit  /  cutting  /  compressing  /  shell-breaking force  /  seed-breaking force
Haonan Zheng, Fang Liang, Yanyan Zhou, Liang Yuan. Experimental research on the mechanical properties of Camellia oleifera fruit shell breaking by cutting and compression[J]. International Journal of Agricultural and Biological Engineering, 2026 , 19 (3) : 307 -313 . DOI: 10.25165/j.ijabe.20261903.10221
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1　Introduction
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Camellia oleifera is a small evergreen tree of Camellia genus in the Camellia family, and it is considered one of the four largest woody edible oil plants, along with olive, palm, and coconut[1-3]. The Camellia oleifera oil extracted from Camellia oleifera fruits can be processed into high-quality edible oil that is nutritious and beneficial to health, and is known as “Oriental olive oil”[4,5]. The Chinese government has made great efforts to develop the Camellia oleifera industry. By 2022, the country’s actual Camellia oleifera forest area was 4.535 million hm2, and the Camellia oleifera seed output was 2.946 Mt[6]. According to the plan of the National Forestry and Grassland Administration of China, the area of Camellia oleifera in China will reach 6 million hm2 by 2025[7].
Camellia oleifera fruit is composed of seeds and a shell, and the shell does not contain oil. Before oil extraction, the Camellia oleifera fruit should be shelled to separate the seeds[8]. Without hulling treatment, the shell will not only affect the quality of oil, but will also cause a certain degree of wear to the oil press machine[9]. The traditional method of artificial hulling is to pile the picked Camellia oleifera fruit for 3-5 d, then spread them out on sunny days for 3-5 d, and finally hull them artificially. During the artificial hulling process, respiration caused by stack retting would cause the consumption of organic matter in Camellia oleifera fruit, resulting in the decrease of the quality and yield of Camellia oleifera oil[10]. Therefore, after picking the Camellia oleifera fruit, it should be shelled and sun-dried as soon as possible to reduce the water content of the Camellia oleifera fruit and minimize the consumption of organic matter. In summary, it is of great significance to carry out the development and related theoretical research of Camellia oleifera fruit husking equipment.
The main shell-breaking methods of Camellia oleifera fruit shucking equipment are impact type, grinding type, cutting type, and extrusion type[11–12]. At present, the goal of Camellia oleifera fruit breaking equipment research is to increase the breaking rate and reduce the damage rate of Camellia oleifera seeds. Lan et al.[13] designed a shelling and sorting machine for Camellia oleifera fruit. A shelling rod which had torsion angle, cone angle, and different radius of gyration was constructed into a wedge-shaped shelling chamber to shell the different kinds of Camellia oleifera fruit. The results showed that shelling rate was more than 99%, and the seed fragmentation rate was less than 3%. Tang et al.[14] designed a four-channel fully automatic shelling machine. Firstly, the Camellia oleifera fruit was graded in four channels, and then the shucking was realized through the impact between Camellia fruit and the shucking casing, as well as the impact, extrusion, and rubbing between Camellia oleifera fruit. The results showed that the shelling rate of the ripe and fresh Camellia oleifera fruit shelling machine was 98.85%, and the seed breakage rate was 3.24%. In addition, Zhu et al.[8] and Meng et al.[15] also carried out the design and experiment of Camellia oleifera fruit shucking equipment.
To further improve the breaking rate of Camellia oleifera fruit and reduce the damage rate of seeds, it is necessary to carry out theoretical research on the breaking compression characteristics of Camellia oleifera fruit. However, there are few studies in this regard, so it is necessary to refer to research on the breaking compression characteristics of other fruits. As described in Huang et al.[16], through the measurement of the physical characteristics of different eastern gamagrass seeds, it was found that the axial shell breaking could effectively reduce the breakage rate of seeds. As described in Rasli et al.[17], mechanical properties were measured using a pendulum impact load test device. The results showed that the values of rupture force and energy for oil palm fruitlets under vertical loading orientation were lower than those under horizontal loading orientation. Meanwhile, the rupture force and energy of oil palm fruitlets decreased as the ripeness stage increased. According to the solid model of chestnut established using ANSYS software, the results show that when the direction of the compressive force is consistent with the direction of the chestnut shell texture, the chestnut is more prone to deformation, as highlighted by Yang and Qi[18]. The research on Camellia oleifera fruit is as follows. As described in Wei et al.[19], using reverse engineering technology and finite element simulation analysis methods, it was found that increased loading displacement decreased the stress on the fruit, making it easier to break the shell of Camellia oleifera by radial extrusion. As described in Yang et al.[3], by studying the structural changes, moisture transfer, and shrinkage strain of the Camellia oleifera shell during the shelling processes, it was found that shelling efficiency of Camellia oleifera fruit can be increased by more than 50% under both natural drying and hot air drying, by damaging the exocarp structure. Furthermore, this study proposed that the stress required for shell breaking was reduced by first cutting the shell and then compressing it, which also reduced the stress applied to Camellia oleifera seeds.
In this study, a Camellia oleifera fruit sheller was proposed, and the compressive mechanical characteristics of Camellia oleifera fruit breakage were tested. Four factors including the number of cutting knives, the cutting direction, the compression direction, and the size of Camellia oleifera fruit were selected, and the influence of these four factors on the shell-breaking force of Camellia oleifera fruit was explored using the control variable method, to provide reference data and a theoretical basis for the design of the Camellia oleifera fruit sheller, to increase the breaking rate of the Camellia oleifera fruit sheller, and to reduce the Camellia oleifera seed damage rate.
2　Materials and methods
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2.1　Structural composition and working principle of Camellia oleifera fruit cutting-extrusion breaking machine
The Camellia oleifera fruit cutting-extrusion breaking machine consists of a classification device, a cutting-extrusion device, and a separation device, as illustrated in Figure 1. The three parts cooperate with each other to complete the process of grading, cutting, extrusion, and separation of Camellia oleifera fruit. When Camellia oleifera fruit enters the hopper, the motor drives the rubber classification conveyor belt, which is arranged to be narrow at the front and wide at the back. The Camellia oleifera fruit on the belt will fall into different collection areas according to their size and then fall into the through-hole of the outer cylinder of the cutting and extrusion device via the bottom opening. Under the drive of the motor, the cutting-extrusion device rotates, and the Camellia oleifera fruit inside the through-hole rotates with it. When it moves to a fixed position, the protrusion on the pressure plate of the roller will squeeze the Camellia oleifera fruit downward, whereupon it will be cut by the tool and fall into the inner cylinder of the cutting and extrusion device. The inner cylinder is equipped with a spiral stirring blade. The Camellia oleifera fruit will be transported axially to the extrusion part with the rotation of the spiral stirring blade. It will be squeezed and rubbed between the roller and the outer cylinder in the extrusion part, and then fall out of the extrusion separation device axially. After being cut and squeezed, the Camellia oleifera fruit falls on the key-type separator riddle of the separation device and is separated by further vibration. Under gravity, the material falls into the structure formed by the toothed roller and the smooth roller. Due to their smooth surface and larger size, the seeds are swept into the collection device by the sweeping plate, while the shells, due to their thin shape, are pulled into the gap between the toothed roller and the smooth roller. Finally, the classification, cutting, extrusion, and separation of Camellia oleifera fruit was completed.
2.2　Design of cutting-extrusion device
The most important part of the Camellia oleifera fruit cutting-extrusion breaking machine is the cutting-extrusion device, as illustrated in Figure 2. It is composed of a cutting device and an extrusion device, which mainly includes an extrusion shaft, a shaft, a cutting tool, a cutting outer cylinder, an extrusion outer cylinder, an extrusion inner plate, a cutting inner cylinder, a spiral blade, an extrusion main roller, an extrusion spring, and an extrusion sub-roller. Camellia oleifera fruit falls into the through-hole of the outer cylinder of the cutting-extrusion device. During rotation, the bulge on the extrusion shaft will squeeze the Camellia oleifera fruit toward the cutting tool, and it will be cut by the tool and fall into the inner cylinder of the shell-breaking device. Camellia oleifera fruit is axially transported to the extrusion device by the spiral blade as it rotates inside the inner cylinder. In the extrusion device, it is squeezed and rubbed between the roller and the outer cylinder, and then leaves the extrusion device and enters the separation device for the separation of Camellia oleifera seeds and shells.
2.3　Experimental materials and environment
Fresh Camellia oleifera fruit purchased from a local market in Wuhan was selected. The internal structure of Camellia oleifera fruits is shown in Figure 3, which consists of three parts: the shell, the column core, and the seed. The number of seeds in each Camellia oleifera fruit ranged from 3 to 8. The center of Camellia oleifera fruit is the column core, and the seeds are distributed around the core as the axis. Mature Camellia oleifera fruit is generally irregular spherical or ellipsoidal, with a particle size ranging from 20 to 50 mm. The shape of seeds is polygonal oval or prismatic, and the thickness of the seeds ranges from 6 to 18 mm. The shell thickness is uneven, generally ranging from 1 to 5 mm. The middle part is thinner than the top, and the multi-petal shell radially converges from all sides to the top.
Vernier calipers were used to measure the long axis diameter of Camellia oleifera fruit. The diameter of Camellia oleifera fruit ranged from 25 mm to 40 mm, and those with a diameter greater than 30 mm accounted for 70%.
The test device is shown in Figure 4. It mainly includes the electronic universal testing machine, Vernier calipers, electronic table scales, cutting tools, and so on. These instruments are located in the laboratory of the Engineering College at Huazhong Agricultural University. The electronic universal testing machine can measure the breaking force and deformation of Camellia oleifera fruit. The pressure sensor is installed on the pressure head of the frame, and the distance between the pressure head and the Camellia oleifera fruit can be controlled via the operation panel.
2.4　Experimental methods
Firstly, the electronic universal testing machine was used to compress Camellia oleifera fruit and Camellia oleifera seeds respectively, and the characteristics of the stress-strain curves were analyzed to determine the breaking force of Camellia oleifera fruit and Camellia oleifera seeds.
Then, the control variable method was used to study the influence of the number of cutting knives, cutting direction, compression direction, and Camellia oleifera fruit size (Camellia oleifera fruit long axis diameter) on the breaking force of Camellia oleifera fruit. In this experiment, other factors were fixed while a single factor was changed to analyze its influence on breaking force and deformation. The factor coding table is listed in Table 1.
Among them, the number of cutting knives is 0 (no cutting), 1, 2, 3, and 4 knives, respectively. The cutting direction is divided into equal angle cutting along the long axis and equidistant cutting rings along the minor axis. The diagram of cutting is shown in Figure 5. The compressing direction is divided into along the major axis and along the minor axis. The Camellia oleifera fruit size is divided into four grades according to the long axis diameter: 20-25 mm, 25-30 mm, 30-35 mm, and 35-40 mm. Based on these four factors, 80 groups of experiments were designed using the control variable method, and each group had three replicates.
In the experiment process, the Camellia oleifera fruit size was measured first, and then the Camellia oleifera fruit was cut according to the requirements of the experiment. After that, the Camellia oleifera fruit was put into the electronic universal testing machine, the distance between the upper pressure head and the Camellia oleifera fruit was adjusted, and the machine was started to compress downward at the set speed. When the compression force on the Camellia oleifera fruit dropped to 50% of its peak value, the compression was stopped, and the pressure sensor recorded the compression process data for subsequent analysis of displacement and load.
3　Results and discussion
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3.1　Analysis of compressive stress-strain curve characteristics of Camellia oleifera fruit
As illustrated in Figure 6, a set of load and displacement relationship diagrams was obtained during the experiment. The compression process of Camellia oleifera fruit is mainly divided into shell elastic deformation stage, shell yield stage, seed elastic deformation stage, and seed yield stage. The coordinate origin represents the moment when the upper pressure plate of the electronic universal testing machine and the Camellia oleifera fruit start to contact and extrude. The segment from the origin to point A is approximately linear, and the relationship between load and displacement is approximately linear. Between origin and point A, the Camellia oleifera fruit shell is in the elastic deformation stage. Point A is the breakage point of the fruit shell, and the corresponding load is the breakage force. With the breakage of the fruit shell, the fruit shell enters the compression yield stage (AB segment). As compression displacement increases, the force exerted by the upper pressing plate on the cracked fruit shell compresses the fruit seeds. The BC segment is the elastic deformation stage of fruit seeds compression of the seeds under compression, and the relationship between load and displacement is linear. As the pressure rises, the fruit seeds fracture at point C and enter the yield stage. Theoretically, the difference between point A and point C is the force required to fracture the seeds.
3.2　Analysis of compressive stress-strain characteristics of Camellia oleifera seeds
To verify that the difference between two peak forces in Figure 6 corresponds to seed-breaking forces, the seeds of Camellia oleifera fruit of the same size were taken out for compression testing, and the relationship between load and displacement of seeds was obtained as shown in Figure 7. The seed compression is mainly divided into an elastic deformation stage and a yield stage. The coordinate origin represents the moment when the upper pressure plate of the electronic universal testing machine contacts the seeds. The segment from the coordinate origin to point A represents the pressing stage: the seeds have a small displacement, no deformation occurs, and the load is small. The AB segment is the compressive elastic deformation stage, and the relationship between load and displacement is linear. At point B, the seeds are fractured and enter the yield stage (BC segment). The corresponding load at point B is the seed-breaking force. According to the test, the seed-breaking force values corresponding to seeds with 1/2 ball, 1/4 ball, and 1/8 ball shapes were 225 N, 223 N, and 141 N, respectively, and the mean value was 196.33 N. The mean value of seed-breaking force was close to the difference between the two peak forces in Figure 6.
3.3　Significance analysis of test factors
The test results were analyzed by ANOVA, and the results are listed in Table 2. The cutting direction had no significant effect on the shell-breaking force of Camellia oleifera fruit (p>0.05), while the number of cutting knives, the compression direction, and the size of Camellia oleifera fruit had significant effects on the shell-breaking force of Camellia oleifera fruit (p<0.01). The results show that the cutting direction has little influence on the shell-breaking force, but the number of cutting knives, the compressing direction, and the size of Camellia oleifera fruit have great influence on the shell-breaking force of Camellia oleifera fruit. The determination of the compression direction and the number of cutting knives is of great significance to the design of Camellia oleifera fruit sheller.
3.4　Influence of cutter number on compressive mechanical properties
The effect of the number of cutting knives on the shell-breaking force is shown in Figure 8. It can be seen from the figure that the greater the number of cutting knives, the smaller the breaking force. The shell-breaking force without cutting is significantly higher than that of cutting 1-4 knives, and there is little difference between cutting 1-4 knives on the reduction of shell-breaking force. The average value was taken for the analysis. The shell-breaking force of Camellia oleifera fruits without cutting ranged from 478.85 to 2117.26 N, and the average shell-breaking force was 1060.05 N. The shell-breaking force of Camellia oleifera fruit with 1 cut ranged from 276.94 to 1575.31 N, and the average shell-breaking force was 740.52 N. The shell-breaking force of Camellia oleifera fruit with 2 cuts ranged from 264.58 to 1076.28 N, and the average shell-breaking force was 650.64 N. The shell-breaking force of Camellia oleifera fruit with 3 cuts ranged from 224.73 to 967.29 N, and the average shell-breaking force was 582.51 N. The shell-breaking force of Camellia oleifera fruit with 4 cuts ranged from 207.31 to 982.22 N, and the average shell-breaking force was 553.92 N. Compared to without cutting, those in the cutting ones decreased by 30.14%, 38.62%, 45.07%, and 47.74%, respectively.
Cutting Camellia oleifera fruit before compression can effectively reduce the shell-breaking force of Camellia oleifera fruit. The greater the number of cutting knives, the smaller the shell-breaking force. However, with the increase of the number of cutting knives, the amplitude of the reduction of shell-breaking force decreases. Compared with the cutting of 1 knife, the reduction degree of the shell-breaking force of the cutting of 2-4 knives is less than 10%. Considering the influence of increasing the number of scratches on the structure and cost of the machine, it is economical and practical to cut with 1 knife.
3.5　Influence of cutting direction on compressive mechanical properties
The effect of the cutting direction on the shell-breaking force is shown in Figure 9. It can be seen from the figure that the two curves are close to coinciding, indicating that there is little difference in the impact of the cutting direction on the shell-breaking force. The shell-breaking force of Camellia oleifera fruit cutting along the long axis ranged from 224.73 to 1575.31 N, and the average shell-breaking force was 658.59 N. The shell-breaking force of Camellia oleifera fruit cutting along the minor axis ranged from 207.31 to 960.01 N, and the average shell-breaking force was 605.22 N. Compared with the Camellia oleifera fruit cut along the long axis direction, the average shell-breaking force of Camellia oleifera fruit cut along the minor axis direction decreased by 8.10%, and the reduction degree of force value was not high. The effect of cutting along the long axis and cutting along the minor axis on the shell-breaking force of Camellia oleifera fruit was not significant (p>0.05). Because the Camellia oleifera fruit is elliptical (like the shape of an egg), it is easily placed vertically along the long axis in the natural state, and it easily achieves equal angle cutting along the long axis. However, equidistant ring cutting along the minor axis requires the tool to rotate radially perpendicular to the long axis, and the long axis of Camellia oleifera fruit has different lengths, so it is especially difficult to achieve ring cutting with equal spacing. Based on the fact that the differences in the effect of cutting along the long axis at equal angles and cutting along the minor axis at equal distances on the shell-breaking force of Camellia oleifera fruit are not significant, and cutting along the minor axis at equal distances is difficult to achieve, it is possible to cut along the long axis at equal angles instead, thereby reducing the shell-breaking force of the Camellia oleifera fruit.
3.6　Influence of compressing direction on compressive mechanical properties
The effect of the compressing direction on the shell-breaking force is shown in Figure 10. As can be seen from the figure, in 96.25% of the experimental groups, the shell-breaking force of Camellia oleifera fruits compressing along the long axis was smaller than that of compressing along the minor axis, and the effects of compressing along the long axis and compressing along the minor axis on shell-breaking force of Camellia oleifera fruits were extremely significant (p<0.01). The shell-breaking force of Camellia oleifera fruit compressing along the minor axis ranged from 264.58 N to 2117.26 N, and the average shell-breaking force was 815.86 N. The breaking force of Camellia oleifera fruit compressing along the long axis ranged from 207.31 to 1186.77 N, and the average shell-breaking force was 619.20 N. Compared with compressing along the minor axis, the average shell-breaking force of Camellia oleifera fruit compressing along the long axis decreased by 24.11%. This is because the fibers of the shell tissue are oriented along the long axis. When the shell is broken, the cracks are distributed along the long axis. Therefore, applying external force along the long axis makes the shell prone to rupture.
3.7　Influence of Camellia oleifera fruit size on compressive mechanical properties
The effect of Camellia oleifera fruit size on shell-breaking force is shown in Figure 11. It can be seen from the figure that the larger the fruit diameter is, the larger the shell-breaking force is. The shell-breaking force of 20-25 mm Camellia oleifera fruit ranged from 207.31 to 572.47 N, and the average shell-breaking force was 362.55 N. The shell-breaking force of 25-30 mm Camellia oleifera fruit ranged from 454.86 to 878.60 N, and the average shell-breaking force was 669.33 N. The shell-breaking force of 30-35 mm Camellia oleifera fruit ranged from 473.66 to 1333.45 N, and the average shell-breaking force was 827.86 N. The shell-breaking force of 35-40 mm Camellia oleifera fruit ranged from 547.21 to 2117.26 N, and the average shell-breaking force was 1011.39 N. The effect of different Camellia oleifera fruit size on the shell-breaking force of Camellia fruit was very significant (p<0.01). Compared with the 20-25 mm Camellia oleifera fruit, the average shell-breaking force of 25-30 mm Camellia oleifera fruit was increased by 85.62%; the average shell-breaking force of 30-35 mm Camellia oleifera fruit was increased by 127.34%; and the average shell-breaking force of 35-40 mm Camellia oleifera fruit was increased by 178.69%. With the increase of Camellia oleifera fruit size, the shell-breaking force of Camellia oleifera fruit will increase accordingly.
3.8　Optimal combination for Camellia oleifera fruit shell breaking by cutting and compression
Using grading measures, making 1 cut along the long axis and compressing along the long axis is the most effective way to crack the shell of Camellia oleifera fruit. Compared with the mechanical property tests of Camellia oleifera fruit (no cutting) conducted by Tang et al.[20] and Xue et al.[21], the test results regarding the influence of the compressing direction and the Camellia oleifera fruit size on compressive mechanical properties were consistent. The shell-breaking force of Camellia oleifera fruit compressing along the long axis was lower than that of Camellia oleifera fruit compressing along the minor axis. With the increase of Camellia oleifera fruit size, the shell-breaking force of Camellia oleifera fruit also increased. However, due to the high moisture content of Camellia oleifera fruit used in this experiment, the value of shell-breaking force measured in this experiment is greater than that measured in the two experiments mentioned above.
4　Conclusions
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To reduce the rate of seed breaking of Camellia oleifera fruit, this paper uses a single-factor test based on the electronic universal testing machine to illustrate the influence law of cutting knife number, cutting direction, compressing direction, and Camellia oleifera fruit size on the extrusion shell-breaking force of Camellia oleifera fruit, which provides theoretical support for the design of grading-cutting-compressing-separating process and machine. The main conclusions are as follows:
(1) The average breaking force of Camellia oleifera seeds was 196.33 N. Cutting could release the stress of Camellia oleifera fruit shell, reduce the stress transferred to the seeds, and reduce the damage rate of Camellia oleifera seeds.
(2) Compared with direct compression without cutting, the shell-breaking force of Camellia oleifera fruit with 1, 2, 3, and 4 cuts decreased by 30.14%, 38.62%, 45.05%, and 47.74%, respectively. However, with the increase of the number of cutting knives, the amplitude of the shell-breaking force reduction of Camellia oleifera fruit decreased. Considering the influence of increasing the number of cutting knives on the structure and cost of the machine and tool, it is economical and practical to cut with one knife.
(3) The effect of cutting direction on shell-breaking force is not significant. Although the shell-breaking force of Camellia oleifera fruit cut at equal distance along the minor axis direction is 8.10% lower than that of Camellia oleifera fruit cut at an equal angle along the long axis direction, the equal angle cutting along the long axis direction can be adopted considering the technical challenges of equidistant cutting along the minor axis direction. The shell-breaking force of Camellia oleifera fruit compressing along the long axis was 24.11% lower than that of Camellia oleifera fruit compressing along the minor axis, making the long axis the appropriate compression direction.
(4) With the increase of Camellia oleifera fruit size, the shell-breaking force of Camellia oleifera fruit also increased. The shell-breaking force of 25-30 mm, 30-35 mm, and 35-40 mm increased by 85.62%, 127.34%, and 178.69%, respectively, compared with the shell-breaking force of 20-25 mm. Grading before shell breaking helps to avoid crushing large fruits and causing seed damage to small fruits due to excessive pressure.
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Year 2026 volume 19 Issue 3
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Article Info
doi: 10.25165/j.ijabe.20261903.10221
  • Receive Date：2025-09-25
  • Online Date：2026-08-27
  • Published：2026-06-30
Article Data
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History
  • Received：2025-09-25
  • Accepted：2026-05-06
Affiliations
    1College of Engineering, Huazhong Agricultural University, Wuhan 430070, China
    2Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River, Ministry of Agriculture and Rural Affairs, Wuhan 430070, China

Corresponding:

Fang Liang, PhD, Professor, research interest: intelligent agricultural machinery. College of Engineering, Huazhong Agricultural University, Wuhan 430070, China. Tel: +86-13871413052, Email: .
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表12种不同金属材料的力学参数
科
Family		 属数
Number of
genus		 种数
Number of
species		 占总种数比例
Percentage of
total species (%)		 属
Genus		 种数
Number of
species		 占总种数比例
Percentage of total
species (%)
鹅膏菌科Amanitaceae 2 11 5.26 鹅膏菌属 Amanita 10 4.78
小菇科 Mycenaceae 2 12 5.74 丝盖伞属 Inocybe 5 2.39
多孔菌科 Polyporaceae 8 14 6.70 蜡蘑属 Laccaria 5 2.39
红菇科 Russulaceae 3 23 11.00 小皮伞属 Marasmius 6 2.87
小菇属 Mycena 11 5.26
光柄菇属 Pluteus 5 2.39
红菇属 Russula 17 8.13
栓菌属 Trametes 5 2.39
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