scholarly journals Are Maize Stalks Efficiently Tapered to Withstand Wind Induced Bending Stresses?

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Kate Seegmiller ◽  
Rajandeep S. Sekhon ◽  
Daniel J. Robertson
Keyword(s):  
Optimization Algorithm ◽  
Bending Strength ◽  
Wind Loading ◽  
Cross Sectional ◽  
Structural Efficiency ◽  
Agricultural Plant ◽  
Bending Stresses ◽  
Hybrid Maize ◽  
Stalk Lodging ◽  
Maize Stalks

AbstractStalk lodging (breaking of agricultural plant stalks prior to harvest) results in millions of dollars in lost revenue each year. Despite a growing body of literature on the topic of stalk lodging, the structural efficiency of maize stalks has not been investigated previously. In this study, we investigate the morphology of mature maize stalks to determine if rind tissues, which are the major load bearing component of corn stalks, are efficiently organized to withstand wind induced bending stresses that cause stalk lodging.945 fully mature, dried commercial hybrid maize stem specimens (48 hybrids, ∼2 replicates, ∼10 samples per plot) were subjected to: (1) three-point-bending tests to measure their bending strength and (2) rind penetration tests to measure the cross-sectional morphology at each internode. The data were analyzed through an engineering optimization algorithm to determine the structural efficiency of the specimens.Hybrids with higher average bending strengths were found to allocate rind tissue more efficiently than weaker hybrids. However, even strong hybrids were structurally suboptimal. There remains significant room for improving the structural efficiency of maize stalks. Results also indicated that stalks are morphologically organized to resist wind loading that occurs primarily above the ear. Results are applicable to selective breeding and crop management studies seeking to reduce stalk lodging rates.HighlightMaize stem morphology was investigated through an optimization algorithm to determine how efficiently their structural tissues are allocated to withstand wind induced bending stresses that cause stalk lodging.

scholarly journals Cross-Sectional Geometry Predicts Failure Location in Maize Stalks

2021 ◽  
Author(s):  
Christopher J Stubbs ◽  
Christopher McMahan ◽  
Kaitlin Tabaracci ◽  
Bharath Kunduru ◽  
Rajandeep S. Sekhon ◽  
...  
Keyword(s):  
Bending Strength ◽  
Critical Role ◽  
Bending Stress ◽  
Lodging Resistance ◽  
Cross Sectional ◽  
Biomechanical Models ◽  
Bending Stresses ◽  
Failure Location ◽  
Stalk Lodging ◽  
Maize Stalks

Abstract Background: Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when high winds induce bending moments in the stalk which exceed the bending strength of the plant. Previous biomechanical models of plant stalks have investigated the effect of cross-sectional morphology on stalk lodging resistance (e.g., diameter and rind thickness). However, it is unclear if the location of stalk failure along the length of stem is determined by morphological or compositional factors. It is also unclear if the crops are structurally optimized, i.e., if the plants allocate structural biomass to create uniform and minimal bending stresses in the plant tissues. The purpose of this paper is twofold: (1) to investigate the relationship between bending stress and failure location of maize stalks, and (2) to investigate the potential of phenotyping for internode-level bending stresses to assess lodging resistance. Results: 868 maize specimens representing 16 maize hybrids were successfully tested in bending to failure. Internode morphology was measured, and bending stresses were calculated. It was found that bending stress is highly and positively associated with failure location. A user-friendly computational tool is presented to help plant breeders in phenotyping for internode-level bending stress. Phenotyping for internode-level bending stresses could potentially be used to breed for more biomechanically optimal stalks that are resistant to stalk lodging. Conclusions: Internode-level bending stress plays a potentially critical role in the structural integrity of plant stems. Equations and tools provided herein enable researchers to account for this phenotype, which has the potential to increase the bending strength of plants without increasing overall structural biomass.

scholarly journals The Effect of Self-Loading on the Mechano-Stability and Stalk Lodging Resistance of Plant Stems

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Yusuf Oduntan ◽  
Tyrone Keep ◽  
Scott D Noble ◽  
Daniel J. Robertson
Keyword(s):  
Structural Integrity ◽  
Bending Strength ◽  
Flexural Rigidity ◽  
Critical Role ◽  
External Loading ◽  
Lodging Resistance ◽  
Plant Weight ◽  
Agricultural Plant ◽  
Generalized Framework ◽  
Stalk Lodging

AbstractBackgroundStalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when bending moments induced by a combination of external loading (e.g. wind) and self-loading (e.g. the plant’s own weight) exceed the bending strength of plant stems. Previous biomechanical plant stem models have investigated both external loading and self-loading of plants, but have evaluated them as separate and independent phenomena. However, these two types of loading are highly interconnected and mutually dependent. The purpose of this paper is twofold: (1) to investigate the combined effect of external loads and plant weight on the displacement and stress state of plant stems / stalks, and (2) to provide a generalized framework for accounting for self-weight during mechanical phenotyping experiments used to predict stalk lodging resistance.ResultsA method of properly accounting for the interconnected relationship between self-loading and external loading of plants stems is presented. The interconnected set of equations are used to produce user-friendly applications by presenting (1) simplified self-loading correction factors for a number of common external loading configurations of plants, and (2) a generalized Microsoft Excel framework that calculates the influence of self-loading on crop stems. The effect of self-loading on the structural integrity of wheat is examined in detail. A survey of several other plants is conducted and the influence of self-loading on their structural integrity is also presented.ConclusionsThe self-loading of plants plays a potentially critical role on the structural integrity of plant stems. Equations and tools provided herein enable researchers to account for the plant’s weight when investigating the flexural rigidity and bending strength of plant stems.

scholarly journals The Effect of Plant Weight on Estimations of Stalk Lodging Resistance

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Yusuf Oduntan ◽  
Tyrone Keep ◽  
Scott D Noble ◽  
Daniel J Robertson
Keyword(s):  
Bending Strength ◽  
Structural Response ◽  
External Loading ◽  
Lodging Resistance ◽  
Plant Weight ◽  
Agricultural Plant ◽  
Flexural Response ◽  
Generalized Framework ◽  
User Friendly ◽  
Stalk Lodging

Abstract Background: Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when bending moments induced by a combination of external loading (e.g. wind) and self-loading (e.g. the plant’s own weight) exceed the stalk bending strength of plant stems. Previous studies have investigated external loading and self-loading of plants as separate and independent phenomena. However, these two types of loading are highly interconnected and mutually dependent. The purpose of this paper is twofold: (1) to investigate the combined effect of external loads and plant weight on the flexural response of plant stems, and (2) to provide a generalized framework for accounting for self-weight during mechanical phenotyping experiments used to predict stalk lodging resistance. Results: A mathematical methodology for properly accounting for the interconnected relationship between self-loading and external loading of plants stems is presented. The method was compared to numerous finite element models of plants stems and found to be highly accurate. The resulting interconnected set of equations from the derivation were used to produce user-friendly applications by presenting (1) simplified self-loading correction factors for common loading configurations of plants, and (2) a generalized Microsoft Excel framework that calculates the influence of self-loading on crop stems. Results indicate that ignoring the effects of self-loading when calculating stalk flexural stiffness is appropriate for large and stiff plants such as maize, bamboo, and sorghum. However, significant errors result when ignoring the effects of self-loading in smaller plants with larger relative grain sizes, such as rice (8% error) and wheat (16% error).Conclusions: Properly accounting for self-weight can be critical to determining the structural response of plant stems. Equations and tools provided herein enable researchers to properly account for the plant’s weight during mechanical phenotyping experiments used to determine stalk lodging resistance.

scholarly journals The Effect of Self-Loading on the Mechano-Stability and Stalk Lodging Resistance of Plant Stems

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Yusuf Oduntan ◽  
Tyrone Keep ◽  
Scott D Noble ◽  
Daniel J Robertson
Keyword(s):  
Structural Integrity ◽  
Bending Strength ◽  
Flexural Rigidity ◽  
Critical Role ◽  
External Loading ◽  
Lodging Resistance ◽  
Plant Weight ◽  
Agricultural Plant ◽  
Generalized Framework ◽  
Stalk Lodging

Abstract Background Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when bending moments induced by a combination of external loading (e.g. wind) and self-loading (e.g. the plant’s own weight) exceed the bending strength of plant stems. Previous biomechanical plant stem models have investigated both external loading and self-loading of plants, but have evaluated them as separate and independent phenomena. However, these two types of loading are highly interconnected and mutually dependent. The purpose of this paper is twofold: (1) to investigate the combined effect of external loads and plant weight on the displacement and stress state of plant stems / stalks, and (2) to provide a generalized framework for accounting for self-weight during mechanical phenotyping experiments used to predict stalk lodging resistance.Results A method of properly accounting for the interconnected relationship between self-loading and external loading of plants stems is presented. The interconnected set of equations are used to produce user-friendly applications by presenting (1) simplified self-loading correction factors for a number of common external loading configurations of plants, and (2) a generalized Microsoft Excel framework that calculates the influence of self-loading on crop stems. The effect of self-loading on the structural integrity of wheat is examined in detail. A survey of several other plants is conducted and the influence of self-loading on their structural integrity is also presented.Conclusions The self-loading of plants plays a potentially critical role on the structural integrity of plant stems. Equations and tools provided herein enable researchers to account for the plant’s weight when investigating the flexural rigidity and bending strength of plant stems.

scholarly journals Integrated Puncture Score: Force-Displacement Weighted Rind Penetration Tests Improve Stalk Lodging Resistance Estimations in Maize

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Christopher McMahan ◽  
Will Seegmiller ◽  
Douglas D Cook ◽  
Daniel J Robertson
Keyword(s):  
Bending Strength ◽  
Penetration Resistance ◽  
Lodging Resistance ◽  
Data Set ◽  
Penetration Testing ◽  
Agricultural Plant ◽  
Power Of The Test ◽  
Score Method ◽  
High Throughput Phenotyping ◽  
Stalk Lodging

Abstract Background: Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Rind penetration resistance tests have been used by plant scientists and breeders to estimate the stalk lodging resistance of maize for nearly a hundred years. However, the rind puncture method has two key limitations: (1) the predictive power of the test decreases significantly when measuring elite or pre-commercial hybrids, and (2) using rind penetration measurements as a breeding metric does not necessarily create stronger stalks. In this study, we present a new rind penetration method called the Integrated Puncture Score, which uses a modified rind penetration testing protocol and a physics-based model to provide a robust measure of stalk lodging resistance. Results: Two datasets, one with a diverse array of maize hybrids and one with only elite hybrids, were evaluated by comparing traditional rind penetration testing and the Integrated Puncture Score method to measurements of stalk bending strength. When evaluating the diverse set of hybrids, both methods were good predictors of stalk bending strength (R2 values of 0.67). However, when evaluating elite hybrids, the Integrated Puncture Score had an R2 value of 0.74 whereas the traditional method had an R2 value of 0.48. Additionally, the Integrated Puncture Score was able to differentiate between the strongest and weakest hybrids in the elite hybrid data set whereas the traditional rind penetration method was not. Additional experiments revealed strong evidence in favor of the data aggregation steps utilized to compute the Integrated Puncture Score. Conclusions: This study presents a new method for evaluating rind penetration resistance that highly correlates with stalk bending strength and can possibly be used as a breeding index for assessing stalk lodging resistance. This research lays the foundation required to develop a field-based high-throughput phenotyping device for stalk lodging resistance.

scholarly journals The Effect of Plant Weight on Estimations of Stalk Lodging Resistance 

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Yusuf Oduntan ◽  
Tyrone Keep ◽  
Scott D Noble ◽  
Daniel J Robertson
Keyword(s):  
Bending Strength ◽  
Structural Response ◽  
External Loading ◽  
Lodging Resistance ◽  
Plant Weight ◽  
Agricultural Plant ◽  
Flexural Response ◽  
Generalized Framework ◽  
User Friendly ◽  
Stalk Lodging

Abstract Background: Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when bending moments induced by a combination of external loading (e.g. wind) and self-loading (e.g. the plant’s own weight) exceed the stalk bending strength of plant stems. Previous studies have investigated external loading and self-loading of plants as separate and independent phenomena. However, these two types of loading are highly interconnected and mutually dependent. The purpose of this paper is twofold: (1) to investigate the combined effect of external loads and plant weight on the flexural response of plant stems, and (2) to provide a generalized framework for accounting for self-weight during mechanical phenotyping experiments used to predict stalk lodging resistance. Results: A mathematical methodology for properly accounting for the interconnected relationship between self-loading and external loading of plants stems is presented. The method was compared to numerous finite element models of plants stems and found to be highly accurate. The resulting interconnected set of equations from the derivation were used to produce user-friendly applications by presenting (1) simplified self-loading correction factors for common loading configurations of plants, and (2) a generalized Microsoft Excel framework that calculates the influence of self-loading on crop stems. Results indicate that ignoring the effects of self-loading when calculating stalk flexural stiffness is appropriate for large and stiff plants such as maize, bamboo, and sorghum. However, significant errors result when ignoring the effects of self-loading in smaller plants with larger relative grain sizes, such as rice (8% error) and wheat (16% error).Conclusions: Properly accounting for self-weight can be critical to determining the structural response of plant stems. Equations and tools provided herein enable researchers to properly account for the plant’s weight during mechanical phenotyping experiments used to determine stalk lodging resistance.

scholarly journals The effect of plant weight on estimations of stalk lodging resistance

Plant Methods ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Christopher J. Stubbs ◽  
Yusuf A. Oduntan ◽  
Tyrone R. Keep ◽  
Scott D. Noble ◽  
Daniel J. Robertson
Keyword(s):  
Bending Strength ◽  
Structural Response ◽  
External Loading ◽  
Lodging Resistance ◽  
Plant Weight ◽  
Agricultural Plant ◽  
Flexural Response ◽  
Generalized Framework ◽  
User Friendly ◽  
Stalk Lodging

Abstract Background Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Stalk lodging occurs when bending moments induced by a combination of external loading (e.g. wind) and self-loading (e.g. the plant’s own weight) exceed the stalk bending strength of plant stems. Previous studies have investigated external loading and self-loading of plants as separate and independent phenomena. However, these two types of loading are highly interconnected and mutually dependent. The purpose of this paper is twofold: (1) to investigate the combined effect of external loads and plant weight on the flexural response of plant stems, and (2) to provide a generalized framework for accounting for self-weight during mechanical phenotyping experiments used to predict stalk lodging resistance. Results A mathematical methodology for properly accounting for the interconnected relationship between self-loading and external loading of plants stems is presented. The method was compared to numerous finite element models of plants stems and found to be highly accurate. The resulting interconnected set of equations from the derivation were used to produce user-friendly applications by presenting (1) simplified self-loading correction factors for common loading configurations of plants, and (2) a generalized Microsoft Excel framework that calculates the influence of self-loading on crop stems. Results indicate that ignoring the effects of self-loading when calculating stalk flexural stiffness is appropriate for large and stiff plants such as maize, bamboo, and sorghum. However, significant errors result when ignoring the effects of self-loading in smaller plants with larger relative grain sizes, such as rice (8% error) and wheat (16% error). Conclusions Properly accounting for self-weight can be critical to determining the structural response of plant stems. Equations and tools provided herein enable researchers to properly account for the plant’s weight during mechanical phenotyping experiments used to determine stalk lodging resistance.

scholarly journals Integrated Puncture Score: Force-Displacement Weighted Rind Penetration Tests Improve Stalk Lodging Resistance Estimations in Maize

2020 ◽  
Author(s):  
Christopher J Stubbs ◽  
Christopher McMahan ◽  
Will Seegmiller ◽  
Douglas D Cook ◽  
Daniel J Robertson
Keyword(s):  
Bending Strength ◽  
Penetration Resistance ◽  
Lodging Resistance ◽  
Data Set ◽  
Penetration Testing ◽  
Agricultural Plant ◽  
Power Of The Test ◽  
Score Method ◽  
High Throughput Phenotyping ◽  
Stalk Lodging

Abstract Background: Stalk lodging (breaking of agricultural plant stalks prior to harvest) is a multi-billion dollar a year problem. Rind penetration resistance tests have been used by plant scientists and breeders to estimate the stalk lodging resistance of maize for nearly a hundred years. However, the rind puncture method has two key limitations: (1) the predictive power of the test decreases significantly when measuring elite or pre-commercial hybrids, and (2) using rind penetration measurements as a breeding metric does not necessarily create stronger stalks. In this study, we present a new rind penetration method called the Integrated Puncture Score, which uses a modified rind penetration testing protocol and a physics-based model to provide a robust measure of stalk lodging resistance.Results: Two datasets, one with a diverse array of maize hybrids and one with only elite hybrids, were evaluated by comparing traditional rind penetration testing and the Integrated Puncture Score method to measurements of stalk bending strength. When evaluating the diverse set of hybrids, both methods performed well, but when evaluating the elite hybrids, the integrated Puncture Score outperformed the traditional rind penetration method. Additionally, the Integrated Puncture Score was able to differentiate the best- and worst-performing hybrids, even in the elite hybrid data set. Additional experiments revealed strong evidence in favor of the data aggregation steps utilized to compute the Integrated Puncture Score.Conclusions: This study presents a new method for evaluating rind penetration resistance that highly correlates with stalk bending strength and can possibly be used as a breeding index for assessing stalk lodging resistance. This research lays the foundation required to develop a field-based high-throughput phenotyping device for stalk lodging resistance.

Evolution of hindlimb posture in nonmammalian therapsids: biomechanical tests of paleontological hypotheses

Paleobiology ◽  
2001 ◽  
Vol 27 (1) ◽  
pp. 14-38 ◽  
Author(s):  
Richard W. Blob
Keyword(s):  
Experimental Data ◽  
Biomechanical Model ◽  
Axial Rotation ◽  
Morphological Data ◽  
Upright Posture ◽  
Cross Sectional ◽  
Model Calculations ◽  
Limb Bones ◽  
Plausible Model ◽  
Bending Stresses

Analyses of limb joint morphology in nonmammalian therapsid “mammal-like reptiles” have suggested that among many lineages, individual animals were capable of shifting between sprawling and upright hindlimb postures, much like modern crocodilians. The ability to use multiple limb postures thus might have been ancestral to the generally more upright posture that evolved during the transition from “mammal-like reptiles” to mammals. Here I derive a biomechanical model to test this hypothesis through calculations of expected posture-related changes in femoral stress for therapsid taxa using different limb postures. The model incorporates morphological data from fossil specimens and experimental data from force platform experiments on iguanas and alligators.Experimental data suggest that the evolutionary transition from sprawling to nonsprawling posture was accompanied by a change in the predominant loading regime of the limb bones, from torsion to bending. Changes in the cross-sectional morphology of the hindlimb bones between sphenacodontid “pelycosaurs” and gorgonopsid therapsids are consistent with the hypothesis that bending loads increased in importance early in therapsid evolution; thus, bending stresses are an appropriate model for the maximal loads experienced by the limb bones of theriodont therapsids. Results from the model used to estimate stresses in these taxa do not refute the use of both sprawling and more upright stance among basal theriodont therapsids. Thus, the hypothesis that the use of multiple postures was ancestral to the more upright posture typical of most mammals is biomechanically plausible. Model calculations also indicate that the axial rotation of the femur typical in sprawling locomotion can reduce peak bending stresses. Therefore, as experimental data from alligators and iguanas suggest, the evolution of nonsprawling limb posture and kinematics in therapsids might have been accompanied by increased limb bone bending stress.

scholarly journals Effect of Post-Process Curing and Washing Time on Mechanical Properties of mSLA Printouts

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4856
Author(s):  
Bartłomiej Nowacki ◽  
Paweł Kowol ◽  
Mateusz Kozioł ◽  
Piotr Olesik ◽  
Jakub Wieczorek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Curing Time ◽  
Cross Sectional ◽  
Post Process ◽  
Order Of Magnitude ◽  
Static Tensile ◽  
High Roughness ◽  
Ambiguous Effect

The article discusses the influence of the post-process on the mechanical properties of elements produced with the use of the mask stereolithography (mSLA) method. Printed samples were subjected to the following post-process steps: Washing and post-curing, at various times. Then, static tensile and static bending tests were carried out, as well as Shore D hardness measurements for the inner and surface part of the sample, as well as profilographometric analysis of the surface. The post-curing time has been found to strongly affect the tensile and bending strength of printouts, and to improve their surface quality. Washing has an ambiguous effect on the strength of the printouts, but, in the end, it was found that extended washing slightly reduces the strength. Washing significantly affects the quality of the printout surface. A washing time that is too short results in a surface that strongly resembles the printing process, with high roughness. Increasing the washing time to 10 min lowers the roughness by one order of magnitude. Post-curing has also been shown to be beneficial for the cured sample with the application of shielding water. This approach results in an improvement in the flexural strength of the printouts. In general, the obtained research results indicate that, for printouts with cross-sectional dimensions of several mm, the optimal washing time is no more than 10 min and the post-curing time is at least 30 min.

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