在分裂霍普金森压力棒测试过程中,细胞混凝土对压力强度增强的结构效应
Ling Zhou1, Zhiping Deng1, Junru Ren1
1Army Logistics Academy, 20 North First Road, College Town, Shapingba District, Chongqing 401311, China.
Materials (Basel, Switzerland)
|February 13, 2025
概括
本研究使用数值分割霍普金森压力杆 (SHPB) 试验研究了细胞混凝土对压力强度的结构效应. 研究结果显示,横向惯性限制显著影响强度,随着孔隙度的增加而下降.
科学领域:
- 材料科学 材料科学 材料科学
- 土木工程 土木工程是指土木工程.
- 材料机械学 材料机械学
背景情况:
- 用球形和超吸收聚合物制造的新型细胞混凝土在压缩下表现出应变率效应.
- 之前的分裂霍普金森压力杆 (SHPB) 测试表明,压力强度的动态增加因子 (DIF) 包括结构效应,而不仅仅是真正的延展率效应.
研究的目的:
- 通过使用扩展的德鲁克-普拉格模型,对新型细胞混凝土动态压缩行为的结构效应进行数值研究.
- 量化横向惯性限制对具有不同孔隙度的细胞混凝土压力强度的影响.
主要方法:
- 数值分割霍普金森压力棒 (SHPB) 测试使用Abaqus有限元素分析软件进行.
- 用扩展的德鲁克-普拉格构成模型来模拟材料的行为.
- 模拟是在70/s,100/s和140/s的应变速率水平上进行的,对孔径为10%至40%的标本进行模拟.
主要成果:
- 由于横向惯性限制,压力强度的增加随着毛孔度的增加而减少,从毛孔度10%的5.9 MPa增加到毛孔度40%的2 MPa (在70/s延展率下).
- 这种横向惯性限制效应的下降趋势,随着孔隙度的增加,在所有测试的应变速率水平 (70/s,100/s,140/s) 上都是一致的.
- 观察到侧面惯性限制效应具有明显的弹性和塑性发展阶段,通过实现动态应力平衡来分开.
结论:
- 侧向惯性限制是一个重要的结构因素,影响在动态负载下测量细胞混凝土的压力强度.
- 这种封闭效应的大小与材料的孔隙性相反相关.
- 了解这些结构效应对于准确解释细胞混凝土中的动态强度增强机制至关重要.
相关概念视频
Relation Between Tensile Strength and Compressive Strength of Concrete
159
Concrete is a fundamental building material, and understanding its strengths is crucial for construction projects. The relationship between its tensile and compressive strengths is intricate, showing that while these strengths are related, they do not increase at the same rate. Tensile strength's growth is slower and is affected by various factors such as the methods used for testing, the size and shape of the specimen, the texture of the aggregate used, and the moisture content of the...
159
Behavior of Concrete Under Compressive Load
141
Concrete exhibits specific behaviors under different compressive loads. Understanding this is crucial for understanding its structural integrity. When concrete undergoes uniaxial compression, it tends to develop cracks that run parallel to the direction of the force. These parallel cracks stem from localized tensile stresses that occur perpendicular to the compression direction. Additionally, angled cracks may appear due to the formation of shear planes.
As the concrete specimen fractures under...
As the concrete specimen fractures under...
141
Strength of Cement
120
Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
120
Impact Strength of Concrete
172
Impact strength in concrete is a critical measure that reflects the material's capability to endure the forces applied during pile driving and when supporting machinery foundations that experience impulsive loads. It is also essential when handling precast concrete components to prevent accidental damage. The impact strength is assessed by observing the concrete's resistance to repeated impacts and energy absorption capacity. A key indicator of significant damage to concrete is when it...
172
Fatigue Strength of Concrete
161
Fatigue, in the context of materials science and engineering, refers to the weakening or failure of a material caused by repeatedly applied loads, even if these loads are below the strength limit of the material. Fatigue strength in concrete is a critical property that influences its durability and longevity. Concrete can fail in two ways due to fatigue. Static fatigue or creep rupture occurs under a constant load or one that increases slowly. The other failure mode is due to cyclical or...
161
Tensile Strength Considerations of Concrete
109
Considering the tensile strength of concrete involves recognizing that the theoretical strength of cement paste can be up to a thousand times higher than what is observed in practical applications. This significant discrepancy is largely attributed to the presence of microscopic cracks within the concrete. These cracks tend to amplify stress at their tips when a load is applied, a phenomenon explained by Griffith's theory of brittle fracture.
The dimensions and shape of a concrete specimen...
The dimensions and shape of a concrete specimen...
109


