Although there are many kinds of fracture tests to choose from in evaluating the crack resistance of asphalt mixture,the semi-circular bending(SCB)test has attracted a lot of attention in the academic road engineering...Although there are many kinds of fracture tests to choose from in evaluating the crack resistance of asphalt mixture,the semi-circular bending(SCB)test has attracted a lot of attention in the academic road engineering community because of its simplicity,stability,and flexibility in testing and evaluation.The SCB test has become a common method to study the cracking resistance of asphalt mixture in recent years.This paper mainly summarizes the overview of the SCB test,summarizes some research results and common characterization parameters of the SCB test method in monotone test and fatigue test in recent years,and predicts and suggests the research direction of the SCB test in the future.It is found that the research on the monotonic SCB test is more comprehensive,and the research on the SCB fatigue test needs to be further improved in the aspects of loading mode,characterization parameter selection,and so on.Researchers can flexibly adjust the geometric dimensions and the test parameters of semi-cylindrical specimens,and conduct comprehensive analysis combined with the results of numerical simulation.The crack resistance of asphalt mixture can be comprehensively evaluated by fracture energy,fracture toughness,stiffness,flexibility index and other fracture indicators,combined with the crack propagation of the specimen.The analysis of numerical simulation can confirm the test results.In order to standardize the setting of fatigue parameters for future application,it is necessary to standardize the setting of bending performance.展开更多
Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually ...Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture （S~） calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper （Ct）. The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel （Bambusa vulgaris Schrad.）, Tali （Gigantochloa apus （BI. Ex Schult. f） Kurz）, Gombong （Gigantochloa verticillata （Willd.） Munro）, and Mayan （Gigantochloa robusta Kurz.） found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test.展开更多
The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this...The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this pressure with the friction and wear generated. Since there are many studies that determine the coefficient of friction in sheet metal forming by bending under tension (BUT) test, the contact pressure between the pin and the sheet was measured using a film that has the ability to record the applied pressure. The vertical force applied to pin was also measured. The results indicate that the vertical force is more accurate to set the contact pressure that using equations predetermined. It was also observed that the contact area between the sheet and the pin is always smaller than the area calculated geometrically. The friction coefficient was determined for the BUT test through several equations proposed by various authors in order to check if there is much variation between the results. It was observed that the friction coefficient showed little variation for each equation, and each one can be used. The material used was the commercially pure aluminum, alloy Al1100.展开更多
In nature,there are widely distributed bi-modulus materials with different deformation characteristics under compressive and tensile stress states,such as concrete,rock and ceramics.Due to the lack of constitutive mod...In nature,there are widely distributed bi-modulus materials with different deformation characteristics under compressive and tensile stress states,such as concrete,rock and ceramics.Due to the lack of constitutive model that could reasonably consider the bi-modulus property of materials,and the lack of simple and reliable measurement methods for the tensile elastic parameters of materials,scientists and engineers always neglect the effect of the bi-modulus property of materials in engineering design and numerical simulation.To solve this problem,this study utilizes the uncoupled strain-driven constitutive model proposed by Latorre and Montáns(2020)to systematically study the distributions and magnitudes of stresses and strains of bi-modulus materials in the three-point bending test through the numerical method.Furthermore,a new method to synchronously measure the tensile and compressive elastic moduli of materials through the four-point bending test is proposed.The numerical results show that the bi-modulus property of materials has a significant effect on the stress,strain and displacement in the specimen utilized in the three-point and four-point bending tests.Meanwhile,the results from the numerical tests,in which the elastic constitutive model proposed by Latorre and Montáns(2020)is utilized,also indicate that the newly proposed measurement method has a good reliability.Although the new measurement method proposed in this study can synchronously and effectively measure the tensile and compressive elastic moduli,it cannot measure the tensile and compressive Poisson’s ratios.展开更多
In this study, the bending test is used to investigate the glass transition temperature for epoxy reinforced with three types ot fibers, fiberglass, Kevlar and synthetic wool, these materials have a wide used in many ...In this study, the bending test is used to investigate the glass transition temperature for epoxy reinforced with three types ot fibers, fiberglass, Kevlar and synthetic wool, these materials have a wide used in many application which they are used composite materials. The glass transition temperature can be measured at the point of inflection for ＂the curve of variation of the deflection and temperature. The results show that, the glass transition temperature is affected by the type of the reinforcement of the composites. On the other hand, the glass transition temperature of the wool composite is higher than the other.展开更多
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(No.51968006).
文摘Although there are many kinds of fracture tests to choose from in evaluating the crack resistance of asphalt mixture,the semi-circular bending(SCB)test has attracted a lot of attention in the academic road engineering community because of its simplicity,stability,and flexibility in testing and evaluation.The SCB test has become a common method to study the cracking resistance of asphalt mixture in recent years.This paper mainly summarizes the overview of the SCB test,summarizes some research results and common characterization parameters of the SCB test method in monotone test and fatigue test in recent years,and predicts and suggests the research direction of the SCB test in the future.It is found that the research on the monotonic SCB test is more comprehensive,and the research on the SCB fatigue test needs to be further improved in the aspects of loading mode,characterization parameter selection,and so on.Researchers can flexibly adjust the geometric dimensions and the test parameters of semi-cylindrical specimens,and conduct comprehensive analysis combined with the results of numerical simulation.The crack resistance of asphalt mixture can be comprehensively evaluated by fracture energy,fracture toughness,stiffness,flexibility index and other fracture indicators,combined with the crack propagation of the specimen.The analysis of numerical simulation can confirm the test results.In order to standardize the setting of fatigue parameters for future application,it is necessary to standardize the setting of bending performance.
文摘Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture （S~） calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper （Ct）. The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel （Bambusa vulgaris Schrad.）, Tali （Gigantochloa apus （BI. Ex Schult. f） Kurz）, Gombong （Gigantochloa verticillata （Willd.） Munro）, and Mayan （Gigantochloa robusta Kurz.） found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test.
文摘The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this pressure with the friction and wear generated. Since there are many studies that determine the coefficient of friction in sheet metal forming by bending under tension (BUT) test, the contact pressure between the pin and the sheet was measured using a film that has the ability to record the applied pressure. The vertical force applied to pin was also measured. The results indicate that the vertical force is more accurate to set the contact pressure that using equations predetermined. It was also observed that the contact area between the sheet and the pin is always smaller than the area calculated geometrically. The friction coefficient was determined for the BUT test through several equations proposed by various authors in order to check if there is much variation between the results. It was observed that the friction coefficient showed little variation for each equation, and each one can be used. The material used was the commercially pure aluminum, alloy Al1100.
基金funding support from the National Key Research and Development Program of China(Grant No.2022YFC3102402)as well as from the National Natural Science Foundation of China(Grant No.51879257).
文摘In nature,there are widely distributed bi-modulus materials with different deformation characteristics under compressive and tensile stress states,such as concrete,rock and ceramics.Due to the lack of constitutive model that could reasonably consider the bi-modulus property of materials,and the lack of simple and reliable measurement methods for the tensile elastic parameters of materials,scientists and engineers always neglect the effect of the bi-modulus property of materials in engineering design and numerical simulation.To solve this problem,this study utilizes the uncoupled strain-driven constitutive model proposed by Latorre and Montáns(2020)to systematically study the distributions and magnitudes of stresses and strains of bi-modulus materials in the three-point bending test through the numerical method.Furthermore,a new method to synchronously measure the tensile and compressive elastic moduli of materials through the four-point bending test is proposed.The numerical results show that the bi-modulus property of materials has a significant effect on the stress,strain and displacement in the specimen utilized in the three-point and four-point bending tests.Meanwhile,the results from the numerical tests,in which the elastic constitutive model proposed by Latorre and Montáns(2020)is utilized,also indicate that the newly proposed measurement method has a good reliability.Although the new measurement method proposed in this study can synchronously and effectively measure the tensile and compressive elastic moduli,it cannot measure the tensile and compressive Poisson’s ratios.
文摘In this study, the bending test is used to investigate the glass transition temperature for epoxy reinforced with three types ot fibers, fiberglass, Kevlar and synthetic wool, these materials have a wide used in many application which they are used composite materials. The glass transition temperature can be measured at the point of inflection for ＂the curve of variation of the deflection and temperature. The results show that, the glass transition temperature is affected by the type of the reinforcement of the composites. On the other hand, the glass transition temperature of the wool composite is higher than the other.
