MarkusNeusinger · github-actions · Jun 21, 2026 · Jun 21, 2026 · Jun 21, 2026
diff --git a/plots/line-stress-strain/implementations/r/ggplot2.R b/plots/line-stress-strain/implementations/r/ggplot2.R
@@ -0,0 +1,275 @@
+#' anyplot.ai
+#' line-stress-strain: Engineering Stress-Strain Curve
+#' Library: ggplot2 3.5.1 | R 4.4.1
+#' Quality: 86/100 | Created: 2026-06-21
+
+library(ggplot2)
+library(dplyr)
+library(ragg)
+
+set.seed(42)
+
+# Theme tokens
+THEME       <- Sys.getenv("ANYPLOT_THEME", "light")
+PAGE_BG     <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
+ELEVATED_BG <- if (THEME == "light") "#FFFDF6" else "#242420"
+INK         <- if (THEME == "light") "#1A1A17" else "#F0EFE8"
+INK_SOFT    <- if (THEME == "light") "#4A4A44" else "#B8B7B0"
+INK_MUTED   <- if (THEME == "light") "#6B6A63" else "#A8A79F"
+
+IMPRINT_PALETTE <- c(
+  "#009E73",  # 1 — brand green (first series)
+  "#C475FD",  # 2 — lavender
+  "#4467A3",  # 3 — blue
+  "#BD8233",  # 4 — ochre
+  "#AE3030",  # 5 — matte red
+  "#2ABCCD",  # 6 — cyan
+  "#954477",  # 7 — rose
+  "#99B314"   # 8 — lime
+)
+
+GRID_COLOR <- adjustcolor(INK, alpha.f = 0.12)
+
+# --- Mild Steel (AISI 1020): elastic + Luders plateau + hardening + necking ---
+E_steel        <- 200000  # Young's modulus (MPa)
+eps_y_steel    <- 0.00125  # upper yield strain
+sig_y_upper    <- 250      # upper yield strength (MPa)
+sig_y_lower    <- 228      # lower yield / Luders plateau (MPa)
+eps_plateau    <- 0.016    # end of Luders plateau
+sig_uts_steel  <- 410      # ultimate tensile strength (MPa)
+eps_uts_steel  <- 0.200    # strain at UTS
+sig_frac_steel <- 355      # engineering stress at fracture (MPa)
+eps_frac_steel <- 0.350    # fracture strain
+
+t_e   <- seq(0, 1, length.out = 40)
+eps_e1 <- t_e * eps_y_steel
+sig_e1 <- E_steel * eps_e1
+
+t_p   <- seq(0, 1, length.out = 70)
+eps_p1 <- eps_y_steel + t_p * (eps_plateau - eps_y_steel)
+sig_p1 <- sig_y_upper + (sig_y_lower - sig_y_upper) * (1 - exp(-12 * t_p)) / (1 - exp(-12))
+
+t_h   <- seq(0, 1, length.out = 130)
+eps_h1 <- eps_plateau + t_h * (eps_uts_steel - eps_plateau)
+sig_h1 <- sig_y_lower + (sig_uts_steel - sig_y_lower) * t_h^0.40
+
+t_n   <- seq(0, 1, length.out = 80)
+eps_n1 <- eps_uts_steel + t_n * (eps_frac_steel - eps_uts_steel)
+sig_n1 <- sig_uts_steel - (sig_uts_steel - sig_frac_steel) * t_n^0.35
+
+steel <- data.frame(
+  strain     = c(eps_e1, eps_p1, eps_h1, eps_n1),
+  stress_mpa = c(sig_e1, sig_p1, sig_h1, sig_n1),
+  material   = "Mild Steel (AISI 1020)"
+)
+
+# --- Aluminum 6061-T6: smooth curve, 0.2% offset yield ---
+E_al       <- 69000   # Young's modulus (MPa)
+sig_02     <- 276     # 0.2% offset yield strength (MPa)
+eps_el_al  <- sig_02 / E_al        # elastic limit strain ~0.004
+eps_02_al  <- eps_el_al + 0.002    # yield strain via 0.2% offset ~0.006
+sig_uts_al  <- 310
+eps_uts_al  <- 0.12
+sig_frac_al <- 285
+eps_frac_al <- 0.17
+
+eps_al <- seq(0, eps_frac_al, length.out = 250)
+sig_al <- ifelse(
+  eps_al <= eps_el_al,
+  E_al * eps_al,
+  pmin(
+    sig_02 + (sig_uts_al - sig_02) *
+      ((eps_al - eps_el_al) / (eps_uts_al - eps_el_al))^0.38,
+    sig_uts_al
+  )
+)
+is_neck_al <- eps_al > eps_uts_al
+sig_al[is_neck_al] <- sig_uts_al - (sig_uts_al - sig_frac_al) *
+  ((eps_al[is_neck_al] - eps_uts_al) / (eps_frac_al - eps_uts_al))^0.55
+
+alum <- data.frame(
+  strain     = eps_al,
+  stress_mpa = pmax(0, sig_al),
+  material   = "Aluminum 6061-T6"
+)
+
+# Combined
+df <- rbind(steel, alum)
+df$material <- factor(df$material,
+                      levels = c("Mild Steel (AISI 1020)", "Aluminum 6061-T6"))
+
+# --- 0.2% offset line for aluminum ---
+offset_df <- data.frame(
+  strain     = c(0.002, eps_02_al),
+  stress_mpa = E_al * c(0.002 - 0.002, eps_02_al - 0.002)
+)
+
+# --- Critical points (yield, UTS, fracture for both materials) ---
+crit <- data.frame(
+  strain = c(
+    eps_y_steel,   eps_uts_steel,   eps_frac_steel,
+    eps_02_al,     eps_uts_al,      eps_frac_al
+  ),
+  stress_mpa = c(
+    sig_y_upper,   sig_uts_steel,   sig_frac_steel,
+    sig_02,        sig_uts_al,      sig_frac_al
+  ),
+  material = factor(
+    c(
+      "Mild Steel (AISI 1020)", "Mild Steel (AISI 1020)", "Mild Steel (AISI 1020)",
+      "Aluminum 6061-T6",       "Aluminum 6061-T6",       "Aluminum 6061-T6"
+    ),
+    levels = c("Mild Steel (AISI 1020)", "Aluminum 6061-T6")
+  )
+)
+
+plot_title <- "line-stress-strain · r · ggplot2 · anyplot.ai"
+
+# --- Plot ---
+p <- ggplot(df, aes(x = strain, y = stress_mpa, color = material)) +
+  geom_line(linewidth = 1.2) +
+  # 0.2% offset dashed line (aluminum)
+  geom_line(
+    data        = offset_df,
+    aes(x = strain, y = stress_mpa),
+    color       = INK_SOFT,
+    linetype    = "dashed",
+    linewidth   = 0.8,
+    inherit.aes = FALSE
+  ) +
+  # Critical points
+  geom_point(
+    data        = crit,
+    aes(x = strain, y = stress_mpa, color = material),
+    size        = 3.5,
+    shape       = 21,
+    fill        = PAGE_BG,
+    stroke      = 1.5,
+    inherit.aes = FALSE
+  ) +
+  scale_color_manual(
+    values = c(
+      "Mild Steel (AISI 1020)" = IMPRINT_PALETTE[1],
+      "Aluminum 6061-T6"       = IMPRINT_PALETTE[2]
+    )
+  ) +
+  # Region boundary vertical guidelines
+  annotate("segment",
+    x = eps_plateau, xend = eps_plateau, y = 0, yend = 440,
+    color = INK_MUTED, linetype = "dotted", linewidth = 0.5
+  ) +
+  annotate("segment",
+    x = eps_uts_steel, xend = eps_uts_steel, y = 0, yend = 440,
+    color = INK_MUTED, linetype = "dotted", linewidth = 0.5
+  ) +
+  # Region labels
+  annotate("text",
+    x = (0 + eps_plateau) / 2, y = 448,
+    label = "Elastic",
+    color = INK_MUTED, size = 3.2, fontface = "italic", hjust = 0.5
+  ) +
+  annotate("text",
+    x = (eps_plateau + eps_uts_steel) / 2, y = 448,
+    label = "Strain Hardening",
+    color = INK_MUTED, size = 3.2, fontface = "italic", hjust = 0.5
+  ) +
+  annotate("text",
+    x = (eps_uts_steel + eps_frac_steel) / 2, y = 448,
+    label = "Necking",
+    color = INK_MUTED, size = 3.2, fontface = "italic", hjust = 0.5
+  ) +
+  # Young's modulus slope indicator (steel, elastic region)
+  annotate("segment",
+    x = 0, xend = 0.00100, y = 0, yend = 200,
+    color = INK_MUTED, linewidth = 1.6
+  ) +
+  annotate("text",
+    x = 0.00110, y = 108,
+    label = "E = 200 GPa", color = INK_MUTED,
+    size = 2.9, fontface = "italic", hjust = 0
+  ) +
+  # Steel critical point labels
+  annotate("text",
+    x = eps_y_steel + 0.004, y = sig_y_upper + 16,
+    label = "YS = 250 MPa", color = IMPRINT_PALETTE[1],
+    size = 3.0, hjust = 0
+  ) +
+  annotate("text",
+    x = eps_uts_steel - 0.002, y = sig_uts_steel + 16,
+    label = "UTS = 410 MPa", color = IMPRINT_PALETTE[1],
+    size = 3.0, hjust = 1
+  ) +
+  annotate("text",
+    x = eps_frac_steel - 0.002, y = sig_frac_steel - 26,
+    label = "Fracture", color = IMPRINT_PALETTE[1],
+    size = 3.0, hjust = 1
+  ) +
+  # Aluminum: 0.2% offset label + critical point labels
+  annotate("text",
+    x = 0.0030, y = 16,
+    label = "0.2% offset line", color = INK_SOFT,
+    size = 2.8, fontface = "italic", hjust = 0
+  ) +
+  annotate("text",
+    x = eps_02_al + 0.004, y = sig_02 - 22,
+    label = "0.2% YS = 276 MPa", color = IMPRINT_PALETTE[2],
+    size = 3.0, hjust = 0
+  ) +
+  annotate("text",
+    x = eps_uts_al + 0.003, y = sig_uts_al + 16,
+    label = "UTS = 310 MPa", color = IMPRINT_PALETTE[2],
+    size = 3.0, hjust = 0
+  ) +
+  annotate("text",
+    x = eps_frac_al - 0.002, y = sig_frac_al - 26,
+    label = "Fracture", color = IMPRINT_PALETTE[2],
+    size = 3.0, hjust = 1
+  ) +
+  labs(
+    title = plot_title,
+    x     = "Engineering Strain (mm/mm)",
+    y     = "Engineering Stress (MPa)",
+    color = "Material"
+  ) +
+  scale_x_continuous(
+    limits = c(0, 0.37),
+    expand = expansion(mult = c(0.01, 0.02))
+  ) +
+  scale_y_continuous(
+    limits = c(0, 460),
+    expand = expansion(mult = c(0.01, 0.02))
+  ) +
+  theme_minimal(base_size = 8) +
+  theme(
+    plot.background   = element_rect(fill = PAGE_BG, color = PAGE_BG),
+    panel.background  = element_rect(fill = PAGE_BG, color = NA),
+    panel.grid.major  = element_line(color = GRID_COLOR, linewidth = 0.3),
+    panel.grid.minor  = element_blank(),
+    panel.border      = element_blank(),
+    axis.line         = element_line(color = INK_SOFT, linewidth = 0.5),
+    axis.ticks        = element_line(color = INK_SOFT, linewidth = 0.4),
+    axis.title        = element_text(color = INK, size = 10),
+    axis.text         = element_text(color = INK_SOFT, size = 8),
+    plot.title        = element_text(color = INK, size = 12, face = "bold",
+                                     margin = margin(b = 8)),
+    plot.margin       = margin(t = 12, r = 16, b = 10, l = 10),
+    legend.background = element_rect(fill = ELEVATED_BG, color = INK_SOFT,
+                                     linewidth = 0.3),
+    legend.text       = element_text(color = INK_SOFT, size = 8),
+    legend.title      = element_text(color = INK, size = 9),
+    legend.position        = "inside",
+    legend.position.inside = c(0.80, 0.22),
+    legend.key.height      = unit(1.0, "lines"),
+    legend.margin          = margin(4, 8, 4, 8)
+  )
+
+# --- Save ---
+ggsave(
+  filename = sprintf("plot-%s.png", THEME),
+  plot     = p,
+  device   = ragg::agg_png,
+  width    = 8,
+  height   = 4.5,
+  units    = "in",
+  dpi      = 400
+)